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There is nothing wrong with Fir plywood for boat building. There are boats around here that are 60 years old and still running strong. The main thing is to keep moisture out of the plywood. Enjoying the videos!
I built my 14' garvey with half inch marine fir plywood almost 20 years ago. I covered the bottom and chine area with 6 oz. glass cloth. Other than a few minor repairs it's held up pretty well on the Willamette River.
Maybe use a weighted pendulum for impact test.. Thing is though, he's giving up his time for us on yt and making such testing devices may be too time consuming taking into account, he has a family and a business to run. U did find humour in those caveman style testa though.. lol
Hi Joe, I am also a licensed boat operator (USCG 100GT) and third generation boat builder, (from concept) I’m diggin’ your videos and the step by step details of your content, Your experience and your articulation make these videos easy to watch and very beneficial for the millions of DIY’ers that are tuning in … Just wanting to give respect where respect is due … Good going, keep up the great work !!.. Also, might add that Coosa offers density options as well, in which case could change test results when testing in comparisons … and it’s better to screw through it than to it . Cheers !!..
Interesting test results. I've been looking at various materials to use in "reimaging" a small sailboat to teach my grandsons to sail. I've watched quite a few videos about repairing old boats, and one of the most frequently needed repairs seems to be wood rot, mostly in deck cores or around fasteners. The most beautiful boat I've ever been aboard was a fiberglass Bristol Channel Cutter with wooden bulwarks. I watched a video of an owner rebuilding his bulwarks some years ago. The sailboat I'm looking at is much smaller, and I'm older and less agile than I once was, so I've planned to add bulwarks and lifelines. I've worked with wood since I was a small boy. My dad died when I was four, and my mother remarried when I was seven. My stepfather owned a tire shop, but he had a woodworking shop for a hobby, and I learned a good bit from him. I've also worked with fiberglass in making modifications to the Formula Fords I once raced. But materials have changed, and I have a lot to learn. I've been looking at synthetics like coosa and divinycell as replacements in different applications. But I still love the feel, the smell and the beauty of a lovely piece of wood. Thank you for your videos.
Glad you enjoyed the video! There are certainly pros and cons to both materials for sure. Sounds like you know what your goals are, and either material could do the job. Coosa is great for weight savings and durability, but wood is Much more pleasant to work with! If wood is encapsulated properly in modern resins, the life and durability really improves. We just released a video about epoxy over plywood. I think it might help you decide what is best for you. Hope this helps, and best of luck with your project!
would love to see a diy coosa project write up-- paddle-board, pram/dinghy, teardrop trailer. just an idea. always daydreaming on new toys! Thanks for the hard work :)
Great video and testing. You If you do furthur testing using fiberglass on both sides of the coosa and both sides of the plywood you will find an exponential increase in strength for both composite systems, almost to the point where the strength of the core becomes irrelevant. The principle is the same a steel I Beam, where the strenth is dramatically increased as the beam depth is increased and the ‘core’ (beam web) is minimal compared to the top and bottom beam flanges. I am a retired structural engineer and have completely rebuilding a 26’ fiberglass landing craft including replacement of longitudinal stringers and decks. When we bought the hull, the previous owner had stripped it down to bare hull, including removal of the floor deck and stringers. The original stringers we glass over wood beams We replaced the stringers by forming a hollow box beam using 1/4” okume plywood because we could easily match the contours of the bottom and deck. We glassed over the hollow beams with two layers of fiberglass roving, using epoxy resin. We then sealed 3/4’ doug fir plywood with epoxy and bonded it to the tops of stringers and to sides of the hull with thickened epoxy and applied heavy fg roving with epoxy resin over the top. We have been using the vessel for commercial shrimping in Prince William Sound, Alaska for about 8 years now. To re T
Yes, I agree glassing it will make it Much stronger! We plan on doing more testing with fiberglass on both sides. Sounds like you guys built an awesome work boat for shrimping! I grew up around the shrimp industry here in the gulf of Mexico as a young man and really enjoyed it. I have also been to Alaska several times, and absolutely enjoyed every minute! Thanks for watching and commenting!
Capt. Joe, I remember a video of you doing the front deck of your 29' boat. You where screwing the coosa down to coosa. Did you predrill and counter sink before you installed screws? Reason I ask is I've worked with coosa a good bit and I've never had any luck laminating pieces together or holding things into the coosa with screws. Usually have to clamp or squish laminations together. Also I've used a strip of wood or made brackets to mount things into or on the coosa. Thanks for the videos, they provide some insight that alot of people really dont knows out there. Coosa and 1708 for example. Most just know "angel hair" CSM or "combo" roven woving
Yes, we usually predrilled and countersink the top layer only, then a very small countersink in the bottom layer, if any at all. We are using the Bluewater 26 pound density, which is the heaviest grade of Coosa. We run the screws pretty close together. There are several videos in the boatbuild series that show us doing that. Hope that helps. Thanks for watching!
@FishBumpTV Thank you for the explanation sir!! Ive worked with the 20lb density a bunch. Never tried the 26lb. It may hold screws a little better vs the 20. May pick some up and give it a shot. My buddies got an old tunnel boat we're about to redo with coosa and poly. May try the 26 in it as well
Once again ! Absolutely great informative videos! Anyone into boating and wanting to learn repair- building process - products Pros and cons from such an experienced professional! This is the place! Years of experience packed into short videos !
Love your content. I found your videos looking for ways to repair my Carolina Skiff and glad I did! Keep up the great work! Recommending you to all my buddies here in Eastern NC
I was wondering if you could do a buoyancy test . A submerging test where they both are waited down 3 to 5 feet in the water for a week or two or there is some pressure to force water into the grain of the wood and the lamination or press in the Coosa and maybe a pull test and a drop test to see how big of a dent they both could withstand simulating dropping something on your deck I’ve become a huge fan. You’re a great teacher and your explanations and the way you explain stuff is excellent thank you so much.
Thanks for the suggestion! I will try to do some more Coosa vs. plywood testing in the future for you all. I'm glad you are enjoying the channel, and I really appreciate you watching and commenting!
Have a question for you. I've seen oriented stranded board (osb) fiberglassed and I'm wondering what is your thoughts on that ? Not everyone in the boating world can afford these high priced plywood. What csm or woven would you recommend for the osb? Could you possibly go through the procedure of that ?
I will have to do some research on that. I have personally never used or seen osb used on any kind of boat work in our area. Wish I could be more help on that subject for you. Thanks for watching!
Fish bump family y'all keeping coming really appreciate your time soaking this up like a sponge moving forward! Looking forward seeing one of the family built boats your father had a hand in building old school fir plywood and glassing maybe a field trip for all the viewers you tube Thanks again for sharing your family legacy!
Hi, Capt Joe! Thanks so much for sharing what you know -- and doing it so well. I have been trying a few little projects with fiberglass for a couple of years and watching other videos as I went. But I have learned a ton from your videos! Please keep making this great content!
Fishermen and Professor no dought- Love your experimentation and insight! We call it Thermolite in OZ and its expensive! Most Caravan Manufactures caught on yrs ago!
Much appreciated!! Yep, it's good, but pricey! Would love to visit your amazing country one of these days. I am pleasantly surprised at how many great folks are watching all the way from Australia 🇦🇺!
There is another advantage to Coosa not many know about, that’s insulation properties, you can build a day box out of it, and have no need for foam. If you need an overnight/ multi day box, double the 3/4 Coosa, or use a poly foam with the Coosa. Very strong, and holds exceptionally. Good channel, thank you
I agree, that is a good point! That aft port and starboard compartments in our custom 29 are built out of 3/4 Coosa and they hold ice very well. I appreciate you watching and commenting!
I’m loving your channel 👍💯 every one is blinded by coosa, because it supposedly doesn’t rot🤷♂️ however I have removed several ( 7 ) transmons from boats that are 5/7 years old and the coosa has delaminated itself😳🤬 I have asked a engineer about this, he thinks , as do I that the material as It moves the Foam in the Material break down and make little balls that work downwards and further exacerbate the problem . People will say glass boats don’t move, that is not correct at all, they are constantly bending and twisting 💯Now don’t say I don’t use it because I do, but my own boat was rebuilt with plywood 🤷♂️ Footnote, I don’t know who did the transom repairs to these boats, I don’t know what resin was used ect, however they all seemed to be constructed with good laminating and tabbing techniques 🤷♂️. 🤗😉🐊🇦🇺
Thanks for watching! That's some interesting feedback on the Coosa. I think both materials can be great if installed properly, but probably lots of poorly done work out there. Hope these vids help folks choose wisely!
I replaced my Tyee Lund transom with Blue Water Coosa. it is definitely lighter and doesn't absorb water. I DID add 2 coats of Gluvit to help with durability. So my Coosa was 675.00 with 220.00 of shipping. The Gluvit was 81.00 a quart. So $986.00 all in. I have also completely rebuilt all furniture in boat and all decking with american marine plywood. The 3/4" american plywood was 156.00 per full sheet. Also epoxied all marine plywood on all 6 sides so that epoxy cost me 224.00 to cover 4 4x8 sheets. I like the stiffening effect of the epoxy for all the wood and it was only 780.00 for decking and ALL wood furniture. The marine plywood would be even cheaper for the transom but the 1-2% coosa water absorbsion trumped cost for the transom. If a guy can afford the Coosa for decking I think that is a great use for Coosa. Coosa works, shapes, and drills better than plywood but WITHOUT adhesive, Coosa drillings aren't as tough as plywood drillings. When I removed all 30 year old decking, the rot was ONLY AT THE fasteners and some end grain. I used Krieg pockets for much of my boat furniture and I believe 18 degree pockets hold better in plywood than the Coosa. Coosa has a brittleness that may be an issue at 1/2" thicknesses if not used as decking. I glued 1/4" of EVA closed cell foam to all wood panels that faced the sky for comfort before gluing down waterproof PVC as the wrap for the decking...so the plywood has a total of 7 layers of waterproofing not counting the plywood's lamination glue.
Thanks for proving me right I always wonder never will take the time to do something like that except for standing on it when I'm done,,,, and when I'm done normally nothing moves because I'm worried about it being strong
This is the first time that I am watching your channel. Based on this experiment alone, you get a "like" and a "subscribe". This is similar to a project that my sone did in middle school. This is clear, understable, real-world science! I am going to look for your other experiment videos. I think it is great for the uninitiated public to see how and what boats are made of.
I wonder if they would perform the same way after glass is applied. Standard amount of fiberglass for a finished product?? Great job!! Keep em coming !!
Hi Joe could you give us an idea of how much fiberglass and resin you would use on about 350sf of plywood? I’m doing a project and it seem a little difficult to figure out exactly what I need. Thanks in advance! Herman
It would depend on how many layers of glass you would be putting on. Plywood needs several layers of fiberglass, plus a couple coats of gelcoat in most cases. 1708 takes around 2 to 3 ounces of resin per square foot to wet out. Your resin supplier should also be able to help you with estimates. Hope this helps, thanks for watching!
@@FishBumpTV thanks so much! You’re doing a great job. I’m just a little apprehensive about starting as I want it to turn out with a professional finish. I will continue to watch and learn.
Thanks for taking the time to do this, if possible please do a soak test with the coosa and 2 part expandable 2lbs foam and 4 lbs, Im asking this cuz every manufacturer claims that the foam is waterproof but you can find alot of videos on TH-cam with boats that have water logged foam.
Thanks for the suggestion! Yes, I have seen a good bit of water soaked foam also. That's why I went with a series of watertight compartments when we built our custom 29 ft charter boat. You might enjoy seeing that in some of our boatbuilding series videos.
My understanding is that bondo brand resin will have wax added to it, and is not really considered laminating resin. We use a high quality iso polyester laminating resin made by polynt on most of our projects. Resins are like many things, there is going to be good, better, and best. I recommend using the best materials you can get if possible. Hope this helps, and good luck with your project!
I haven't seen that to be a problem at all. It is designed to work on boats, and other high stress and flex applications. Our 29 ft charter boat, which covered almost 5000 miles over big water this year, is built using coosa board for all of its structural members, and I haven't had any cracks develop. I have several other videos, including a whole series dedicated to documenting the build of our 29 here on the channel. I'm sure you will find those videos informative. I hope this helps, and thanks for watching!
The interesting thing that comes to mind is how the two materials can affect how the boat sets and performs. I would think depending on hull design one could offer an advantage over the other
Thanks for watching from 🇦🇺! I have had some issues in the past with gelcoat/ flowcoat over epoxy, but I think we may do some testing with that soon, as it is a common question these days. Thanks for the suggestion!
We always make the stringers with two layers, and stagger the joints. That way you can make a stringer as long as you need. I have a stringer and transom video here on the channel with a demo piece showing how you would do the staggered joint. I hope this helps and thanks for watching!
This test is simple but practical reminder that the application of newer carbon based materials has specific and significant technological advantages in todays boating world. However, pound for pound, "old school" materials derived from mother nature have been around for thousands of years and still continue to remind us all of how to balance boating needs with renewable resources such as plywood, and still maintain superior strength while doing so. For my 2 cents... I'll stick with take the plywood for stringer repair. Great topic for the channel!
Great video's Capt. Just came across your channel and it was a blast from the past. Pretty sure we fished together way back in the day in your pirogues and at my house in OB. Solid content!
The only thing thats keeping me from making the switch is "fastener holding". Like it looks like screws would easily pull through/strip etc. What about bolting up an outboard; would the coosa just compress and crack the fiberglass? If youre looking for experiment suggestions, put some screws into them and see what it takes to pull them out etc. Thanks for the video!
The only marine plywood I trust is marine BS1088 or Ovkume type plywood. It has a full 30 min WBP (water and boil proof). I have a 1/4” plywood kayak built by stitch and polyester fiberglass taped joints , varnish else where, I built at school in 1974 and it still exists in one piece!!! The real problem with plywood is while encapsulation can make a very good product the idiots that come along later and drill hole in it , once that moisture gets in it will rot any plywood sooner or later. Love that Coosa! Cheers Warren
Fish bump family WOW very impressive the plywood really surprised ! I'm sure when glassed would make a huge difference as well . wasn't sure when lamination of transoms do you put CSM between the layers would love to see how well one of the boats your family built how well it's longevity after years of service when properly sealing plywood Thanks for another great video !
Would love to see this same drop test applied to both standing upright on edge where the real strength is rather than on the flat. Good stuff man i love these in your face here it is videos👊👏
Good suggestion! The materials are surprisingly hard to take to the point of failure with the amount of weights I had on hand at the time. I may do some more testing in the future. Thanks for watching!
I discovered your channel a couple weeks ago and echo all the good things you've already heard! I've been a fairly avid student of the University of TH-cam, and your DIY tutorials are easily among the very best I've seen! I have a selfish request: I'm getting ready to do a repair on a rotten section of deck core on a 36 ft sailboat. Although there are a lot of videos out there on repairing soft decks, they vary widely and they don't take the sort of methodical approach that you guys do. Any chance you could do a master class for us on that? I'd really like to do this repair one time the right way! Thanks! (By the way, if you've already done this and I just missed it, please just point me in the right direction.)
Thanks so much, and welcome to the channel! I will try to do a video or at least touch on the subject of soft core and deck rot for you guys. Glad the videos are helpful and thanks for watching!
Another fantastic video. It would be very insightful if you could provide more information of the type of plywood (brand/type) and type of coosa (bluewater 32? 26?). Again thank you very much for all your content and the time spent to show us how its done. Greetings from Australia.
Thanks, I appreciate the suggestion! The plywood was marine Fir 3/4 inch which I think would be 19mm and the Coosa was Bluewater 26. Hope this helps and I appreciate you watching from Australia 🇦🇺
I really love your videos - well done. Just wondering how you go about doing the structural design work for a boat? For example, for coosa board what thickness to use for what size boat and how close together the stringers are etc. Is there a book/manual or software you use or???
Thanks! I literally grew up in the boat shop. My father was a professional boatbuilder, and it is what or family has always done. We have lots of experience and we research and test alot. But it's always best to overbuild than underbuild something, especially a boat. Hope this helps, thanks for watching
I'll take high quality true marine plywood every time. It's all about the quality of the lay up. For example, The wood in my two 25 ft Bertram's and my 20 Bertram was as solid as the day it was built. But my poorly constructed 1989 proline 230 was a rotten mess when I tore it apart. Not a solid piece of wood found in the boat. Good information, nice channel.
Good. Future videos: 1. How did you get the 2900 hull design? It would be entertaining to learn your hull plug mold process. 2. Water damage management: Is it possible to fully seal? How do you remove water from the places it isn't supposed to be? Houses don't have long term sealed chambers. 3. Aluminum vs polyethylene fuel tanks
Hi! Great video! What are your thoughts on having coosa as a subfloor for a campervan? Would it be overkill? I will be using the campervan for snowboarding, trail running, and just adventures. There will inevitably be spills. I was initially going to go with HDO plywood.
I do know of people using coosa board in campers and rvs. It is designed to be a rot free marine plywood replacement. It is 3 to 4 times more expensive, and the bare surface of coosa needs to be covered or sealed if you would be making contact with your skin. But it should last forever and it is very light and strong. I hope this helps and thanks for watching!
During the first impact, the Coosa board flexed downward to the point it was then being supported by the what appears to be a foam underlayment for a micro second.
Yes, it did. I didn't see that till after publishing the video. The Coosa still did pretty well in that test comparatively. I use both materials a lot, and they both have good qualities. Thanks for Watching and commenting!
Great video! I am currently having a Dusky restored I had reached out to see if you would build me a 29 like you have but ended up going with a 256 dusky
I think you should be testing the final product, since both plywood and coosa are going to be encapsulated in fiberglass & resin. Plywood won't crack unless fiberglass does so. How must flexibility fiberglass has over the length of a boat?
Hey Joe I’m sorry to bother you but I’ve got a I believe it’s a 70 s model thunder craft boat I just bought got to do little work on it but i love your videos and it’s teaching me to do my own work on my boat but how do you go about changing the color of the boat mines a white & blue would love to change the gel coat could you tell me how or do a video on it or do you have a video about it I’m trying to get caught up on all your videos thanks a lot Hubert
Glad the videos are helpful, and we appreciate you watching. Changing hull colors with gelcoat can be pretty labor intensive, especially if it is two tone. You might want to consider going with a marine grade 2 part paint system like awlgrip if you are looking to get a glossy finish on it. I will try to discuss the pros and cons of gelcoat vs paint systems soon for you guys. Hope this helps!
Hi mate I like your experiments however just a thought on the drop test. The experiment with the weights, the coosa showed a lot of flex so with that in mind was there enough of space between the coosa and rubber mat to allow for the flex of the coosa or did the coosa flex just enough for the mat to absorb some of the impact stopping the coosa from breaking specially on the 2nd and 3rd go. I've just bought a boat that needs a new transom and floor and thinking about using coosa as well. keep up the good videos mate Cheers
I will probably be doing some more Coosa board tests in the future, with more range and maybe some fiberglass applied to the surface. Thanks for taking the time to watch and comment!
I been considering using coosa to build a custom 20 foot canoe with it, but its expensive. Even marine plywood is expensive for what I want I even thought using regular wood and go crazy with fiberglass, lots of epoxy and total boat products here in Tuscaloosa county, I want to add center console to run lights, vhf mobile transceivers. Am/fm etc.
Great video on the coosa board. How is the coosa's strength for screwing things to the deck such as a seat or live well things of that nature. I'm going to replace back half of my deck with 1/2 coosa sandwiched between the bottom and top layer of fiberglass. Will need to secure things with screws and wondering how secure they'll be.
The 26 pound density Coosa holds screws ok, but not as good as plywood in my opinion. We try to thru bolt the hardware with machine screws , washer and lock nut when when possible. You might want to do some testing to see if it will hold good enough for your application. I hope this helps, and best of luck with your project!
Sorry if this has been asked or pointed out already, I did not read all 200+ comments... Considering plywood that is used in a marine application has to be encapsulated in fiberglass vs Coosa that does not; would it be a more fair comparison to first encapsulate the plywood in fiberglass prior to the test? And similarly how does each material benefit from being laid up with fiberglass?
How would have built the 29’ differently if you were to use plywood? Secondly what is your plan if murphy shows up and you now have water in the bilge?
We have built quite a few fiberglass hulled boats with marine plywood superstructure that has been encapsulated heavy with fiberglass. If done correctly it can last last many decades. But you guys should use which ever product that you feel best suits your needs. Thanks for watching!
I'm a big fan of Coosa for the hull panels. I used plywood for all the internal structure and Coosa for the hull. That means I never need to worry about rot from a gouge in the hull. Eventually everyone runs into a rock or log.
Hi Joe...It is an impressing series you have put together, showing us of your boat building adventure. And it is very educational as well - I wanted to comment earlier, but as I only found your series this morning you cost me a whole day of working on my own estate ... in stead I learned a lot about boatbuilding through 24 episodes of building a boat - and you are doing a fantastic job building that 29 foot boat, and running your channel!! One question...? Is it correct, that you molded the whole boat in fiberclass only? no sandwich construction of the hull? no PVC or wood as a strengthener? For me, or maybe others, please keep up your awesome work with building, testing, and filming!! ( I am not a native English speaker, so please forgive my bad language or spelling)
Wow, thanks! Yes, the hull is solid fiberglass laminate. We used 26 pound density Coosa board for all of the stringers, transom, decks etc. Glad you are enjoying the boat building series and I appreciate you watching!
How many layers of fiberglass would you say is the least amount you'd use inside the hull of your boat? I watched how you did multiple layers & tied the bottom to the Sides & then the Sides to the top edge in a manner that made it almost like one complete piece. Back to my question, did you roughly use 3 layers or more & I can see using additional layers between surfaces. I'm only asking a ballpark number ; like 4-5 layers in the bottom? Just a basic general number if I can ask? Good video, I've been on a lot of these now. peace
Usually the larger the boat, the more layers of glass you would use. On my 29 we did 2 layers of 1 Oz csm for a skin coat, then 6 alternating layers of 1708 and 1808, 3 of each. Then the stringers were glassed in with 3 layers of 1708, and one more 1708 tying all the spaces between the stringers together. So most of the bottom is 10 to 12 layers thick. Hull sides are 2 layers of 1 Oz csm then 6 layers alternating of 1708 and 1808. That makes for a very solid boat, and may be a little overkill, but I don't want to be worried about if she is going to hold together when it's rough. I hope this helps and thanks for watching!
Thank you for all of that...... while I'm lost you've talked about various "grades" of glass & that will prompt me to research deeper using what you did as my baseline. Yup, I'm not afraid of the prep & hard work as much as I'm afraid of F#@Kin' it Up & having to redo something b/c I didn't do it right the first time. Anyway I look at it, I'm learning so I TY very much!
Great video and a great discussion. 😁👍 your videos are always informative 😁 I use coosa board in my construction and it’s proven to be the superior option.
Like watching all your videos very helpful I have a question I am wanting to build my own 16 17 ft skiff what is a good company to look for fiberglass molds so I can build my skiff out of fiberglass.
Thanks! I don't have a particular company that I could recommend. I know there are always used molds for sale on some different boat forums. Wish I had more for you on that topic.
Your channel has so many great tips, tutorials, and tests. Deserves a lot more views and wish you all the success! Does the Coosa have the same screw/nail holding power, or clamping resistance in case of a through bolt?
Thank you very much! The Coosa comes in different densities, we use the Bluewater 26 which is there heaviest. It is very comparable to plywood in many ways. I may do some testing on that for you guys.
@@FishBumpTV Nice! Appreciate your hard work making these videos. Maybe someday you'll feel comfortable making a Patreon page to get the income you deserve for all this time invested.
Seems if you applied Poly over the Coosa it would be more forgiving and flexible than epoxy over the plywood or maybe even epoxy over the Coosa since epoxy is more brittle after it has set up. What are your thoughts. And your charter is Coosa how do the seams look at the transom and where the floor meets the sides (chine) Do you have a inboard or outboard motors on the gray 29'. Great video!
It would be interesting to redo the cantilever beam test, but laminate fiberglass on both sides of each piece. My thinking is that once you laminate glass over coosa it will be just as strong as glass over ply. Do a relatively heavy ply like 10-20 oz/sq yd.
Very nice to have you watching from 🇬🇷! From what I understand Coosa board and thermolite are very similar materials. I will try to do some research on that for you guys.
Great video Capt! I love what y'all do!! Was that 3/4" Coosa 15# Density? When I first learned about Coosa Bluewater 26, I was told Plywood has a density of 26 pounds per cubic foot and the Bluewater 26 was equal to Plywood. I wonder what how the same test would compare if you used the Bluewater 26. We used 26# Coosa in the Transom, 20# in the Stringers and 15# in the decks, bulkheads and Console of "Wicked Wanda". I may have to duplicate your test for my own curiosity!! Great work!I love seeing your channel blow up!! I also have to say if we could source Plywood comparable to the material used in the 1969 Bertram I am restoring, I would definitely consider building with it today!!
Thank you! We used the Bluewater 26 in the test and for everything in our custom 29. I am a big fan of the Coosa products, but it was interesting to see how it compared to good marine fir plywood. Thanks for watching and commenting.
Has anyone ever used Trespa it's a composite wood fiber that is in a resin and is semi flexible but 100% as strong as aluminum and 100% oil or water or even absorb any liquid chemical resistant and can be cut with a skillsaw blade but it's heavy
I am from Lillian Al !! I love the Skiff Idea Be cool to sell the Kit and Have a Group of Guys build it along with you !!! I would be in and Love to have a Skiff. I currently live in Marathon Florida Keys. Great VIDEOS !! The Best Thanks again
I have a 20' angler. I have completely restored it. Im putting the new floor down and im using 1/2" coosa. I have replaced all 5 stringers with Coosa. I was wondering how many layers of 1808 should I put down in your opinion? Also i am wondering how to bolt down the console and leaning post? Any information and ideas would be greatly appreciated.
Sounds like a great project! We used the 3/4 Bluewater 26 in our 29, but we used 1 layer of 1708 and 1 layer of 1 Oz csm on the main decks and doubled that on the corners. We resin coated the bottoms of most of the the panels to seal them, but no glass. On some of the panels with a larger span, we did put I layer of 1708 on the bottom. You can see much of what we did in our boatbuilding series of videos here on our channel. Of course every boat is different and the amount of glass or core can vary from boat to boat. We actually fiberglassed our console to the deck on our boat. Hope this helps and thanks for watching
@FishBumpTV yes sir that helps alot. It has been a fun project. I did watch the video about glossing the floor of your 29' . I went back with 1/2" only because there was 1/2" originally. Thank you again for your videos and information.
I myself prefer the plywood over Coosa primarily because of the price but also I'd rather be throwing a bunch of saw dust around over a bunch of itchy Coosa fiber dust, just my 2 cents, ❤ the video tests tho!!
Yes, I agree about the Coosa dust! Not pleasant stuff! A good shop vac catching the dust while cutting, and a good tyvek suit really help though. Thanks for watching and commenting
Hey there Joe, I have a question… If I am doing 5 knots with the outboard and I am in the Gulf Stream going with it and the current speed is 6 knots, what effect will it have on my speed???
As the filler core (coosa/ply) in the main essentially take the shear loads and little of the bending moments. it would be a more real world test to place typical POLYESTER LAMINATE on both sides of the test sample before load testing the samples. The laminate will take the load and the core is there only to keep the laminates apart. the drop testing onto the core samples is not indicative of real world testing of load capability. Consider, a flexible elastic band drop testing it does not load the sample as the band just stretches. using a flexible core in a composite that has a rigid laminate provides inconclusive results if you only test the core material. The testing needs to be on representative samples of the finished composite. none the less, great video , great channel.
Coosa board is nothing like low density light weight cores that rely on laminate for the vast majority of their strength and stiffness. In fact Coosa board can be used as a direct replacement for marine plywood decks and panels such as are used on pontoon boat deck for example with no lamination required at all. True, laminating some glass on the coosa board would add stiffness and strength, but so would laminating the plywood. So glassing the sample pieces would not considerably change the results in this test. I hope this helps clarify things. Thanks for watching
Now with a Ti core? Oh, you said you still have to work for a living 😀. Nice videos what's interesting, is fiberglass blows carbon away in side load tests.
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How about testing them with glass applied.
I think we will. I appreciate the suggestion!
There is nothing wrong with Fir plywood for boat building. There are boats around here that are 60 years old and still running strong. The main thing is to keep moisture out of the plywood. Enjoying the videos!
Lol I don't think people realize that's where boats were made of for most of human history, to say wood doesn't belong in a boat is wild
Haha, I know right!
Sounds interesting! Thanks for the comment
Thanks for your thoughts!
I agree, thanks for your thoughts!
I built my 14' garvey with half inch marine fir plywood almost 20 years ago. I covered the bottom and chine area with 6 oz. glass cloth. Other than a few minor repairs it's held up pretty well on the Willamette River.
Very nice, thanks for your comment!
Coosa is much more flexing as we have seen in the first test. For the impact test, it needs much more ground clearance. Very well made video!
Glad you enjoyed it, I think we will do a round 2 with more fiberglass and more clearance, so stay tuned!
You just sold me on Coosa, a boat needs flex, the flex isn't a bug, it's a feature.
Maybe use a weighted pendulum for impact test..
Thing is though, he's giving up his time for us on yt and making such testing devices may be too time consuming taking into account, he has a family and a business to run.
U did find humour in those caveman style testa though.. lol
Glad you enjoyed the video! I used Coosa in the 26 pound density in our custom 29, and am very happy so far. Thanks for watching!
Hi Joe, I am also a licensed boat operator (USCG 100GT) and third generation boat builder, (from concept) I’m diggin’ your videos and the step by step details of your content, Your experience and your articulation make these videos easy to watch and very beneficial for the millions of DIY’ers that are tuning in … Just wanting to give respect where respect is due … Good going, keep up the great work !!..
Also, might add that Coosa offers density options as well, in which case could change test results when testing in comparisons … and it’s better to screw through it than to it . Cheers !!..
Wow, thanks for watching and I appreciate the comment!
Might have been fun to load the ply with bricks to failure. Good time Captain!!
Yes, maybe on the next test we do! Thanks for watching
Thank you, first of all, for your time. Enjoyed my 3rd video from y’all. I might need to go back to the first video. Mahalo from the land down under
Thanks for watching all the way from Australia 🇦🇺 Glad you are enjoying the videos!
Interesting test results. I've been looking at various materials to use in "reimaging" a small sailboat to teach my grandsons to sail. I've watched quite a few videos about repairing old boats, and one of the most frequently needed repairs seems to be wood rot, mostly in deck cores or around fasteners. The most beautiful boat I've ever been aboard was a fiberglass Bristol Channel Cutter with wooden bulwarks. I watched a video of an owner rebuilding his bulwarks some years ago. The sailboat I'm looking at is much smaller, and I'm older and less agile than I once was, so I've planned to add bulwarks and lifelines. I've worked with wood since I was a small boy. My dad died when I was four, and my mother remarried when I was seven. My stepfather owned a tire shop, but he had a woodworking shop for a hobby, and I learned a good bit from him. I've also worked with fiberglass in making modifications to the Formula Fords I once raced. But materials have changed, and I have a lot to learn. I've been looking at synthetics like coosa and divinycell as replacements in different applications. But I still love the feel, the smell and the beauty of a lovely piece of wood. Thank you for your videos.
Glad you enjoyed the video! There are certainly pros and cons to both materials for sure. Sounds like you know what your goals are, and either material could do the job. Coosa is great for weight savings and durability, but wood is Much more pleasant to work with! If wood is encapsulated properly in modern resins, the life and durability really improves. We just released a video about epoxy over plywood. I think it might help you decide what is best for you. Hope this helps, and best of luck with your project!
would love to see a diy coosa project write up-- paddle-board, pram/dinghy, teardrop trailer. just an idea. always daydreaming on new toys! Thanks for the hard work :)
Thanks for the idea! I appreciate you watching!
Great video and testing. You
If you do furthur testing using fiberglass on both sides of the coosa and both sides of the plywood you will find an exponential increase in strength for both composite systems, almost to the point where the strength of the core becomes irrelevant. The principle is the same a steel I Beam, where the strenth is dramatically increased as the beam depth is increased and the ‘core’ (beam web) is minimal compared to the top and bottom beam flanges.
I am a retired structural engineer and have completely rebuilding a 26’ fiberglass landing craft including replacement of longitudinal stringers and decks. When we bought the hull, the previous owner had stripped it down to bare hull, including removal of the floor deck and stringers. The original stringers we glass over wood beams
We replaced the stringers by forming a hollow box beam using 1/4” okume plywood because we could easily match the contours of the bottom and deck. We glassed over the hollow beams with two layers of fiberglass roving, using epoxy resin. We then sealed 3/4’ doug fir plywood with epoxy and bonded it to the tops of stringers and to sides of the hull with thickened epoxy and applied heavy fg roving with epoxy resin over the top.
We have been using the vessel for commercial shrimping in Prince William Sound, Alaska for about 8 years now.
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Yes, I agree glassing it will make it Much stronger! We plan on doing more testing with fiberglass on both sides. Sounds like you guys built an awesome work boat for shrimping! I grew up around the shrimp industry here in the gulf of Mexico as a young man and really enjoyed it. I have also been to Alaska several times, and absolutely enjoyed every minute! Thanks for watching and commenting!
Capt. Joe, I remember a video of you doing the front deck of your 29' boat. You where screwing the coosa down to coosa. Did you predrill and counter sink before you installed screws? Reason I ask is I've worked with coosa a good bit and I've never had any luck laminating pieces together or holding things into the coosa with screws. Usually have to clamp or squish laminations together. Also I've used a strip of wood or made brackets to mount things into or on the coosa. Thanks for the videos, they provide some insight that alot of people really dont knows out there. Coosa and 1708 for example. Most just know "angel hair" CSM or "combo" roven woving
Yes, we usually predrilled and countersink the top layer only, then a very small countersink in the bottom layer, if any at all. We are using the Bluewater 26 pound density, which is the heaviest grade of Coosa. We run the screws pretty close together. There are several videos in the boatbuild series that show us doing that. Hope that helps. Thanks for watching!
@FishBumpTV Thank you for the explanation sir!! Ive worked with the 20lb density a bunch. Never tried the 26lb. It may hold screws a little better vs the 20. May pick some up and give it a shot. My buddies got an old tunnel boat we're about to redo with coosa and poly. May try the 26 in it as well
Once again ! Absolutely great informative videos! Anyone into boating and wanting to learn repair- building process - products
Pros and cons from such an experienced professional! This is the place! Years of experience packed into short videos !
Awesome, thank you! I really appreciate the comment!
Love your content. I found your videos looking for ways to repair my Carolina Skiff and glad I did! Keep up the great work! Recommending you to all my buddies here in Eastern NC
Thanks, glad to help!
I was wondering if you could do a buoyancy test . A submerging test where they both are waited down 3 to 5 feet in the water for a week or two or there is some pressure to force water into the grain of the wood and the lamination or press in the Coosa and maybe a pull test and a drop test to see how big of a dent they both could withstand simulating dropping something on your deck
I’ve become a huge fan. You’re a great teacher and your explanations and the way you explain stuff is excellent thank you so much.
Thanks for the suggestion! I will try to do some more Coosa vs. plywood testing in the future for you all. I'm glad you are enjoying the channel, and I really appreciate you watching and commenting!
Have a question for you.
I've seen oriented stranded board (osb) fiberglassed and I'm wondering what is your thoughts on that ?
Not everyone in the boating world can afford these high priced plywood. What csm or woven would you recommend for the osb?
Could you possibly go through the procedure of that ?
I will have to do some research on that. I have personally never used or seen osb used on any kind of boat work in our area. Wish I could be more help on that subject for you. Thanks for watching!
Fish bump family y'all keeping coming really appreciate your time soaking this up like a sponge moving forward! Looking forward seeing one of the family built boats your father had a hand in building old school fir plywood and glassing maybe a field trip for all the viewers you tube Thanks again for sharing your family legacy!
That's awesome, more to come! Hope to tour one of our older 37s very soon. Thanks so much for watching!
I’m goin to repair my boat floor following your instruction and videos,thank you for your TH-cam Chanel
Glad to help, and best of luck with your project!
On my tiny boat build, we used marine plywood for the upper decks and Coosa on the floors. All heavily epoxied and covered with vinyl.
Sounds like a great project! Thanks for watching and commenting!
Appreciate yr video bc u spoke abt the difference in cost.
Thanks, glad you are enjoying the videos!
Hi, Capt Joe! Thanks so much for sharing what you know -- and doing it so well. I have been trying a few little projects with fiberglass for a couple of years and watching other videos as I went. But I have learned a ton from your videos! Please keep making this great content!
Glad to help! I truly appreciate your encouragement and support of the channel. Best of luck with your projects!
Maybe a Live feed with questions and answers too would be great
Thanks for the suggestion!
Fishermen and Professor no dought- Love your experimentation and insight! We call it Thermolite in OZ and its expensive! Most Caravan Manufactures caught on yrs ago!
Much appreciated!! Yep, it's good, but pricey! Would love to visit your amazing country one of these days. I am pleasantly surprised at how many great folks are watching all the way from Australia 🇦🇺!
There is another advantage to Coosa not many know about, that’s insulation properties, you can build a day box out of it, and have no need for foam. If you need an overnight/ multi day box, double the 3/4 Coosa, or use a poly foam with the Coosa. Very strong, and holds exceptionally. Good channel, thank you
I agree, that is a good point! That aft port and starboard compartments in our custom 29 are built out of 3/4 Coosa and they hold ice very well. I appreciate you watching and commenting!
Practicality and your experience. I work in the boat industry and are very informative to me, which I can take to our clients. Thank you.
You are very welcome, glad to help!
I’m loving your channel 👍💯 every one is blinded by coosa, because it supposedly doesn’t rot🤷♂️ however I have removed several ( 7 ) transmons from boats that are 5/7 years old and the coosa has delaminated itself😳🤬 I have asked a engineer about this, he thinks , as do I that the material as It moves the Foam in the Material break down and make little balls that work downwards and further exacerbate the problem . People will say glass boats don’t move, that is not correct at all, they are constantly bending and twisting 💯Now don’t say I don’t use it because I do, but my own boat was rebuilt with plywood 🤷♂️
Footnote, I don’t know who did the transom repairs to these boats, I don’t know what resin was used ect, however they all seemed to be constructed with good laminating and tabbing techniques 🤷♂️. 🤗😉🐊🇦🇺
Thanks for watching! That's some interesting feedback on the Coosa. I think both materials can be great if installed properly, but probably lots of poorly done work out there. Hope these vids help folks choose wisely!
I replaced my Tyee Lund transom with Blue Water Coosa. it is definitely lighter and doesn't absorb water. I DID add 2 coats of Gluvit to help with durability. So my Coosa was 675.00 with 220.00 of shipping. The Gluvit was 81.00 a quart. So $986.00 all in. I have also completely rebuilt all furniture in boat and all decking with american marine plywood. The 3/4" american plywood was 156.00 per full sheet. Also epoxied all marine plywood on all 6 sides so that epoxy cost me 224.00 to cover 4 4x8 sheets. I like the stiffening effect of the epoxy for all the wood and it was only 780.00 for decking and ALL wood furniture. The marine plywood would be even cheaper for the transom but the 1-2% coosa water absorbsion trumped cost for the transom. If a guy can afford the Coosa for decking I think that is a great use for Coosa. Coosa works, shapes, and drills better than plywood but WITHOUT adhesive, Coosa drillings aren't as tough as plywood drillings. When I removed all 30 year old decking, the rot was ONLY AT THE fasteners and some end grain. I used Krieg pockets for much of my boat furniture and I believe 18 degree pockets hold better in plywood than the Coosa. Coosa has a brittleness that may be an issue at 1/2" thicknesses if not used as decking. I glued 1/4" of EVA closed cell foam to all wood panels that faced the sky for comfort before gluing down waterproof PVC as the wrap for the decking...so the plywood has a total of 7 layers of waterproofing not counting the plywood's lamination glue.
Wow, sounds like a great project! Thanks for sharing your experiences and thanks for watching!
I would like to see the difference plywood to coosa on edge and glassed, as some else motioned.
Very informative, Thanks!
Great suggestion! Thanks
It’d be interesting to see the strength difference after resin and then fiberglass is applied!
Thanks for the suggestion and for watching!
Awesome content. We are rebuilding a jet ski on TH-cam and noticed a big hole in the bottom. Learning a lot from your channel to get it fixed.
Thanks, glad the videos help! Best of luck with your project
I have a 24 foot Triton bay boat that is bult with coosa board.20 years old and still solid as a rock.
Yes, it is good stuff! Thanks for watching
Just stumbled across your channel a few days ago and I LOVE IT !! Subscribed !!
Awesome! Welcome aboard!
I like Your channel because its just the right amount of practical experience and profound knowledge. Liked and subcribed - Greetings from Germany!
Welcome aboard! Thanks for watching all of the way from Germany 🇩🇪!
Thanks for proving me right I always wonder never will take the time to do something like that except for standing on it when I'm done,,,, and when I'm done normally nothing moves because I'm worried about it being strong
You are welcome! Glad to help!
This is the first time that I am watching your channel. Based on this experiment alone, you get a "like" and a "subscribe". This is similar to a project that my sone did in middle school. This is clear, understable, real-world science! I am going to look for your other experiment videos. I think it is great for the uninitiated public to see how and what boats are made of.
Welcome to the channel and thanks for watching!
I wonder if they would perform the same way after glass is applied. Standard amount of fiberglass for a finished product?? Great job!! Keep em coming !!
I think we will have to try that soon. Thanks for the suggestion!
Hmmmm looks like a combination of the two,,lam. together would be great,,,,wonder the best way to connect ?
Haha, sounds like an interesting experiment! We might have to try that.
Hi Joe could you give us an idea of how much fiberglass and resin you would use on about 350sf of plywood? I’m doing a project and it seem a little difficult to figure out exactly what I need. Thanks in advance! Herman
It would depend on how many layers of glass you would be putting on. Plywood needs several layers of fiberglass, plus a couple coats of gelcoat in most cases. 1708 takes around 2 to 3 ounces of resin per square foot to wet out. Your resin supplier should also be able to help you with estimates. Hope this helps, thanks for watching!
@@FishBumpTV thanks so much! You’re doing a great job. I’m just a little apprehensive about starting as I want it to turn out with a professional finish. I will continue to watch and learn.
Thanks for taking the time to do this, if possible please do a soak test with the coosa and 2 part expandable 2lbs foam and 4 lbs, Im asking this cuz every manufacturer claims that the foam is waterproof but you can find alot of videos on TH-cam with boats that have water logged foam.
Thanks for the suggestion! Yes, I have seen a good bit of water soaked foam also. That's why I went with a series of watertight compartments when we built our custom 29 ft charter boat. You might enjoy seeing that in some of our boatbuilding series videos.
You already published, great ! Thanks you for the production and the edicationnal porpose of your videos !
Glad you like them!
Greetings Joe. I am in the process of laminating the floor of my boat. I am using bondo resin, do you think it can be used? thank you
My understanding is that bondo brand resin will have wax added to it, and is not really considered laminating resin. We use a high quality iso polyester laminating resin made by polynt on most of our projects. Resins are like many things, there is going to be good, better, and best. I recommend using the best materials you can get if possible. Hope this helps, and good luck with your project!
@@FishBumpTV thank my friend
You guys do the very best videos on these topics!
Wow, thank you!
Great content! Inspiring. I keep my boat at Homeport. I will swing by sometime and introduce myself. I enjoy and appreciate your content.
Awesome, give me a call!
With the coosa when it's glassed in, will it cause stress cracks and fracture's in the grp if it's more flexible than the ply?
I haven't seen that to be a problem at all. It is designed to work on boats, and other high stress and flex applications. Our 29 ft charter boat, which covered almost 5000 miles over big water this year, is built using coosa board for all of its structural members, and I haven't had any cracks develop. I have several other videos, including a whole series dedicated to documenting the build of our 29 here on the channel. I'm sure you will find those videos informative. I hope this helps, and thanks for watching!
FANTASTIC yall are awesome for making this. your love for the industry is evident !ytyty for making this
Thank you so much!
The interesting thing that comes to mind is how the two materials can affect how the boat sets and performs. I would think depending on hull design one could offer an advantage over the other
Yes, I agree, thanks for watching!
Hi Capt - am enjoying your vids here in Australia. Would love to hear your take on putting gel coat/flow coat over epoxy.
Thanks for watching from 🇦🇺! I have had some issues in the past with gelcoat/ flowcoat over epoxy, but I think we may do some testing with that soon, as it is a common question these days. Thanks for the suggestion!
Another great video! Thanks!
Glad you enjoyed it! Thanks for watching
How do you make 11" x 14' stringer wrapped in fiberglass when plywood or coosa only comes in 8'
We always make the stringers with two layers, and stagger the joints. That way you can make a stringer as long as you need. I have a stringer and transom video here on the channel with a demo piece showing how you would do the staggered joint. I hope this helps and thanks for watching!
This test is simple but practical reminder that the application of newer carbon based materials has specific and significant technological advantages in todays boating world. However, pound for pound, "old school" materials derived from mother nature have been around for thousands of years and still continue to remind us all of how to balance boating needs with renewable resources such as plywood, and still maintain superior strength while doing so. For my 2 cents... I'll stick with take the plywood for stringer repair. Great topic for the channel!
Thanks for your thoughts, and thanks for watching!
Great video's Capt. Just came across your channel and it was a blast from the past. Pretty sure we fished together way back in the day in your pirogues and at my house in OB. Solid content!
Very cool, give me a call sometimes, we will have to catch up! Thanks for watching and commenting
The only thing thats keeping me from making the switch is "fastener holding". Like it looks like screws would easily pull through/strip etc. What about bolting up an outboard; would the coosa just compress and crack the fiberglass?
If youre looking for experiment suggestions, put some screws into them and see what it takes to pull them out etc. Thanks for the video!
The only marine plywood I trust is marine BS1088 or Ovkume type plywood. It has a full 30 min WBP (water and boil proof).
I have a 1/4” plywood kayak built by stitch and polyester fiberglass taped joints , varnish else where, I built at school in 1974 and it still exists in one piece!!!
The real problem with plywood is while encapsulation can make a very good product the idiots that come along later and drill hole in it , once that moisture gets in it will rot any plywood sooner or later.
Love that Coosa!
Cheers Warren
Thanks for your thoughts and suggestions. I appreciate you watching
Does coosa have a grain direction like plywood? Like it would be stronger if a force was applied to it from a different direction
Fish bump family WOW very impressive the plywood really surprised ! I'm sure when glassed would make a huge difference as well . wasn't sure when lamination of transoms do you put CSM between the layers would love to see how well one of the boats your family built how well it's longevity after years of service when properly sealing plywood Thanks for another great video !
Thanks 👍 I think we will be doing some more testing with plywood and Coosa, with fiberglass added. Stay tuned!
Good info, thanks. I especially appreciate the list of advantages/disadvantages.
Thanks, glad to help!
Would love to see this same drop test applied to both standing upright on edge where the real strength is rather than on the flat. Good stuff man i love these in your face here it is videos👊👏
Good suggestion! The materials are surprisingly hard to take to the point of failure with the amount of weights I had on hand at the time. I may do some more testing in the future. Thanks for watching!
I discovered your channel a couple weeks ago and echo all the good things you've already heard! I've been a fairly avid student of the University of TH-cam, and your DIY tutorials are easily among the very best I've seen! I have a selfish request: I'm getting ready to do a repair on a rotten section of deck core on a 36 ft sailboat. Although there are a lot of videos out there on repairing soft decks, they vary widely and they don't take the sort of methodical approach that you guys do. Any chance you could do a master class for us on that? I'd really like to do this repair one time the right way! Thanks! (By the way, if you've already done this and I just missed it, please just point me in the right direction.)
Thanks so much, and welcome to the channel! I will try to do a video or at least touch on the subject of soft core and deck rot for you guys. Glad the videos are helpful and thanks for watching!
Another fantastic video. It would be very insightful if you could provide more information of the type of plywood (brand/type) and type of coosa (bluewater 32? 26?). Again thank you very much for all your content and the time spent to show us how its done. Greetings from Australia.
Thanks, I appreciate the suggestion! The plywood was marine Fir 3/4 inch which I think would be 19mm and the Coosa was Bluewater 26. Hope this helps and I appreciate you watching from Australia 🇦🇺
I really love your videos - well done. Just wondering how you go about doing the structural design work for a boat? For example, for coosa board what thickness to use for what size boat and how close together the stringers are etc. Is there a book/manual or software you use or???
Thanks! I literally grew up in the boat shop. My father was a professional boatbuilder, and it is what or family has always done. We have lots of experience and we research and test alot. But it's always best to overbuild than underbuild something, especially a boat. Hope this helps, thanks for watching
I'll take high quality true marine plywood every time. It's all about the quality of the lay up. For example, The wood in my two 25 ft Bertram's and my 20 Bertram was as solid as the day it was built. But my poorly constructed 1989 proline 230 was a rotten mess when I tore it apart. Not a solid piece of wood found in the boat.
Good information, nice channel.
Good. Future videos:
1. How did you get the 2900 hull design? It would be entertaining to learn your hull plug mold process.
2. Water damage management:
Is it possible to fully seal? How do you remove water from the places it isn't supposed to be?
Houses don't have long term sealed chambers.
3. Aluminum vs polyethylene fuel tanks
All good suggestions, thank you!
Hi! Great video! What are your thoughts on having coosa as a subfloor for a campervan? Would it be overkill? I will be using the campervan for snowboarding, trail running, and just adventures. There will inevitably be spills. I was initially going to go with HDO plywood.
I do know of people using coosa board in campers and rvs. It is designed to be a rot free marine plywood replacement. It is 3 to 4 times more expensive, and the bare surface of coosa needs to be covered or sealed if you would be making contact with your skin. But it should last forever and it is very light and strong. I hope this helps and thanks for watching!
During the first impact, the Coosa board flexed downward to the point it was then being supported by the what appears to be a foam underlayment for a micro second.
Yes, it did. I didn't see that till after publishing the video. The Coosa still did pretty well in that test comparatively. I use both materials a lot, and they both have good qualities. Thanks for Watching and commenting!
Great video! I am currently having a Dusky restored I had reached out to see if you would build me a 29 like you have but ended up going with a 256 dusky
Thanks, glad you are enjoying the videos! Congrats on the new boat
I think you should be testing the final product, since both plywood and coosa are going to be encapsulated in fiberglass & resin. Plywood won't crack unless fiberglass does so. How must flexibility fiberglass has over the length of a boat?
Maybe I missed it but which density of coosa did you use? And what kind of marine ply?
The Coosa is the Bluewater 26 pound density, and the ply was 3/4 marine fir. Thanks for watching
Hey Joe I’m sorry to bother you but I’ve got a I believe it’s a 70 s model thunder craft boat I just bought got to do little work on it but i love your videos and it’s teaching me to do my own work on my boat but how do you go about changing the color of the boat mines a white & blue would love to change the gel coat could you tell me how or do a video on it or do you have a video about it I’m trying to get caught up on all your videos thanks a lot Hubert
Glad the videos are helpful, and we appreciate you watching. Changing hull colors with gelcoat can be pretty labor intensive, especially if it is two tone. You might want to consider going with a marine grade 2 part paint system like awlgrip if you are looking to get a glossy finish on it. I will try to discuss the pros and cons of gelcoat vs paint systems soon for you guys. Hope this helps!
Which density Coosa you were testing? I may have missed you mention it.
Great vids
It is the 3/4 inch thick bluewater 26, that is their highest density core. thanks for watching!
Hi mate I like your experiments however just a thought on the drop test. The experiment with the weights, the coosa showed a lot of flex so with that in mind was there enough of space between the coosa and rubber mat to allow for the flex of the coosa or did the coosa flex just enough for the mat to absorb some of the impact stopping the coosa from breaking specially on the 2nd and 3rd go.
I've just bought a boat that needs a new transom and floor and thinking about using coosa as well.
keep up the good videos mate
Cheers
I will probably be doing some more Coosa board tests in the future, with more range and maybe some fiberglass applied to the surface. Thanks for taking the time to watch and comment!
I been considering using coosa to build a custom 20 foot canoe with it, but its expensive. Even marine plywood is expensive for what I want I even thought using regular wood and go crazy with fiberglass, lots of epoxy and total boat products here in Tuscaloosa county, I want to add center console to run lights, vhf mobile transceivers. Am/fm etc.
Yes, everything is pricey these days. Best of luck with your project!
Great video on the coosa board. How is the coosa's strength for screwing things to the deck such as a seat or live well things of that nature. I'm going to replace back half of my deck with 1/2 coosa sandwiched between the bottom and top layer of fiberglass. Will need to secure things with screws and wondering how secure they'll be.
The 26 pound density Coosa holds screws ok, but not as good as plywood in my opinion. We try to thru bolt the hardware with machine screws , washer and lock nut when when possible. You might want to do some testing to see if it will hold good enough for your application. I hope this helps, and best of luck with your project!
Sorry if this has been asked or pointed out already, I did not read all 200+ comments...
Considering plywood that is used in a marine application has to be encapsulated in fiberglass vs Coosa that does not; would it be a more fair comparison to first encapsulate the plywood in fiberglass prior to the test?
And similarly how does each material benefit from being laid up with fiberglass?
How would have built the 29’ differently if you were to use plywood? Secondly what is your plan if murphy shows up and you now have water in the bilge?
We have built quite a few fiberglass hulled boats with marine plywood superstructure that has been encapsulated heavy with fiberglass. If done correctly it can last last many decades. But you guys should use which ever product that you feel best suits your needs. Thanks for watching!
I'm a big fan of Coosa for the hull panels. I used plywood for all the internal structure and Coosa for the hull. That means I never need to worry about rot from a gouge in the hull. Eventually everyone runs into a rock or log.
Yep, I am a big fan of the Coosa! Thanks for watching and commenting!
Hi Joe...It is an impressing series you have put together, showing us of your boat building adventure. And it is very educational as well - I wanted to comment earlier, but as I only found your series this morning you cost me a whole day of working on my own estate ... in stead I learned a lot about boatbuilding through 24 episodes of building a boat - and you are doing a fantastic job building that 29 foot boat, and running your channel!! One question...? Is it correct, that you molded the whole boat in fiberclass only? no sandwich construction of the hull? no PVC or wood as a strengthener? For me, or maybe others, please keep up your awesome work with building, testing, and filming!! ( I am not a native English speaker, so please forgive my bad language or spelling)
Wow, thanks! Yes, the hull is solid fiberglass laminate. We used 26 pound density Coosa board for all of the stringers, transom, decks etc. Glad you are enjoying the boat building series and I appreciate you watching!
How many layers of fiberglass would you say is the least amount you'd use inside the hull of your boat? I watched how you did
multiple layers & tied the bottom to the Sides & then the Sides to the top edge in a manner that made it almost like one complete
piece. Back to my question, did you roughly use 3 layers or more & I can see using additional layers between surfaces. I'm only
asking a ballpark number ; like 4-5 layers in the bottom? Just a basic general number if I can ask? Good video, I've been on a
lot of these now. peace
Usually the larger the boat, the more layers of glass you would use. On my 29 we did 2 layers of 1 Oz csm for a skin coat, then 6 alternating layers of 1708 and 1808, 3 of each. Then the stringers were glassed in with 3 layers of 1708, and one more 1708 tying all the spaces between the stringers together. So most of the bottom is 10 to 12 layers thick. Hull sides are 2 layers of 1 Oz csm then 6 layers alternating of 1708 and 1808. That makes for a very solid boat, and may be a little overkill, but I don't want to be worried about if she is going to hold together when it's rough. I hope this helps and thanks for watching!
Thank you for all of that...... while I'm lost you've talked about various "grades" of glass & that will prompt me to research
deeper using what you did as my baseline. Yup, I'm not afraid of the prep & hard work as much as I'm afraid of F#@Kin'
it Up & having to redo something b/c I didn't do it right the first time. Anyway I look at it, I'm learning so I TY very much!
Great video and a great discussion. 😁👍 your videos are always informative 😁 I use coosa board in my construction and it’s proven to be the superior option.
Thanks so much! Yes, I agree the Coosa is great product. I appreciate the comment
OSHA says, don't stand on oil cans, otherwise TY for the video
Haha, good to know! Thanks for watching
Thank You. Please keep making videos about coosa.
You got it! Thanks for the suggestion
I am now a fan of Coosa!
Yes, it is good stuff!
Like watching all your videos very helpful I have a question I am wanting to build my own 16 17 ft skiff what is a good company to look for fiberglass molds so I can build my skiff out of fiberglass.
Thanks! I don't have a particular company that I could recommend. I know there are always used molds for sale on some different boat forums. Wish I had more for you on that topic.
Your channel has so many great tips, tutorials, and tests. Deserves a lot more views and wish you all the success! Does the Coosa have the same screw/nail holding power, or clamping resistance in case of a through bolt?
Thank you very much! The Coosa comes in different densities, we use the Bluewater 26 which is there heaviest. It is very comparable to plywood in many ways. I may do some testing on that for you guys.
@@FishBumpTV Nice! Appreciate your hard work making these videos. Maybe someday you'll feel comfortable making a Patreon page to get the income you deserve for all this time invested.
Seems if you applied Poly over the Coosa it would be more forgiving and flexible than epoxy over the plywood or maybe even epoxy over the Coosa since epoxy is more brittle after it has set up. What are your thoughts. And your charter is Coosa how do the seams look at the transom and where the floor meets the sides (chine) Do you have a inboard or outboard motors on the gray 29'. Great video!
Could you please do a how to video on how to fix stress cracks
It would be interesting to redo the cantilever beam test, but laminate fiberglass on both sides of each piece. My thinking is that once you laminate glass over coosa it will be just as strong as glass over ply. Do a relatively heavy ply like 10-20 oz/sq yd.
Thanks for the suggestion! We might try that some day.
Good morning from Greece, is the thermolite panel the same as Coosa? In Europe we have thermolite
Very nice to have you watching from 🇬🇷! From what I understand Coosa board and thermolite are very similar materials. I will try to do some research on that for you guys.
Great video Capt! I love what y'all do!! Was that 3/4" Coosa 15# Density? When I first learned about Coosa Bluewater 26, I was told Plywood has a density of 26 pounds per cubic foot and the Bluewater 26 was equal to Plywood. I wonder what how the same test would compare if you used the Bluewater 26. We used 26# Coosa in the Transom, 20# in the Stringers and 15# in the decks, bulkheads and Console of "Wicked Wanda". I may have to duplicate your test for my own curiosity!! Great work!I love seeing your channel blow up!! I also have to say if we could source Plywood comparable to the material used in the 1969 Bertram I am restoring, I would definitely consider building with it today!!
Thank you! We used the Bluewater 26 in the test and for everything in our custom 29. I am a big fan of the Coosa products, but it was interesting to see how it compared to good marine fir plywood. Thanks for watching and commenting.
Has anyone ever used Trespa it's a composite wood fiber that is in a resin and is semi flexible but 100% as strong as aluminum and 100% oil or water or even absorb any liquid chemical resistant and can be cut with a skillsaw blade but it's heavy
Hey just was wondering what kind of Coosa are u using here?
Nautica or Bluewater?
It is the Bluewater 26. Thanks for watching!
Thanks for the video. This is the exact type of information I’m looking for.
Glad it was helpful! Thanks for watching!
Do the same hanging weight test but have the coosa and plywood sit in a bucket of water for a day before the test
I am from Lillian Al !! I love the Skiff Idea Be cool to sell the Kit and Have a Group of Guys build it along with you !!! I would be in and Love to have a Skiff. I currently live in Marathon Florida Keys. Great VIDEOS !! The Best Thanks again
That's awesome! I really appreciate you watching, and your suggestion on the skiff build. Who knows, maybe we will do some classes at some point!
I have a 20' angler. I have completely restored it. Im putting the new floor down and im using 1/2" coosa. I have replaced all 5 stringers with Coosa. I was wondering how many layers of 1808 should I put down in your opinion? Also i am wondering how to bolt down the console and leaning post? Any information and ideas would be greatly appreciated.
Sounds like a great project! We used the 3/4 Bluewater 26 in our 29, but we used 1 layer of 1708 and 1 layer of 1 Oz csm on the main decks and doubled that on the corners. We resin coated the bottoms of most of the the panels to seal them, but no glass. On some of the panels with a larger span, we did put I layer of 1708 on the bottom. You can see much of what we did in our boatbuilding series of videos here on our channel. Of course every boat is different and the amount of glass or core can vary from boat to boat. We actually fiberglassed our console to the deck on our boat. Hope this helps and thanks for watching
@FishBumpTV yes sir that helps alot. It has been a fun project. I did watch the video about glossing the floor of your 29' . I went back with 1/2" only because there was 1/2" originally. Thank you again for your videos and information.
I myself prefer the plywood over Coosa primarily because of the price but also I'd rather be throwing a bunch of saw dust around over a bunch of itchy Coosa fiber dust, just my 2 cents, ❤ the video tests tho!!
Yes, I agree about the Coosa dust! Not pleasant stuff! A good shop vac catching the dust while cutting, and a good tyvek suit really help though. Thanks for watching and commenting
Hey there Joe, I have a question…
If I am doing 5 knots with the outboard and I am in the Gulf Stream going with it and the current speed is 6 knots, what effect will it have on my speed???
I am sure you probably answered this but, can you use coosa for the hulls???
Yes, you can use it for a hull. Basically anywhere plywood would or could be used you can use Coosa. Thanks for watching!
As the filler core (coosa/ply) in the main essentially take the shear loads and little of the bending moments. it would be a more real world test to place typical POLYESTER LAMINATE on both sides of the test sample before load testing the samples. The laminate will take the load and the core is there only to keep the laminates apart.
the drop testing onto the core samples is not indicative of real world testing of load capability. Consider, a flexible elastic band drop testing it does not load the sample as the band just stretches.
using a flexible core in a composite that has a rigid laminate provides inconclusive results if you only test the core material. The testing needs to be on representative samples of the finished composite.
none the less, great video , great channel.
Coosa board is nothing like low density light weight cores that rely on laminate for the vast majority of their strength and stiffness. In fact Coosa board can be used as a direct replacement for marine plywood decks and panels such as are used on pontoon boat deck for example with no lamination required at all. True, laminating some glass on the coosa board would add stiffness and strength, but so would laminating the plywood. So glassing the sample pieces would not considerably change the results in this test. I hope this helps clarify things. Thanks for watching
Now with a Ti core? Oh, you said you still have to work for a living 😀. Nice videos
what's interesting, is fiberglass blows carbon away in side load tests.
Thanks for watching!