What If We Put A Racing Prop On It - New Pocket Rocket Is Ocean Ready
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- เผยแพร่เมื่อ 24 ส.ค. 2024
- The new fast boat hits the water for the final round of tests and Upgrades! Now let's go on a remote island ocean adventure!
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Hi Rod, I used to work at a boat dealership and there was a program most shops used called "prop calc" to work out what pitch and diameter prop was required. Basically you just input the hull type, boat weight and motor type and it would give you a couple of options to try, saved a heap of time water testing new props. That was over 10yrs ago so I would think they have something better by now.
Staino props are better in all aspects other than the hit to your wallet. The blades flex far less than ali and the net result is more torque and better response.
Also mate the extra cav plate on your new motors leg would suggest it has a longer shaft. Could be 5 inches different in leg length compared to that 9.9. They amount of spray getting kicked up definitely looks like it's still sitting to low even with the extra 3cm you raised it. I'd try getting it up higher and if that works look into shortening the shaft, should be easy enough to do with that motor.
Hope that drivel helps, happy boating man
Hey Rod, this is why you are one of the best. No BS pretending you got it right the first time, you showed us the situation not working quite right, took on feedback and tried to fix the problem all live on camera.
Yeah Rod, I went into Oz props here on the Sunny Coast and got a hydrofoil after seeing the difference it made in your 1st vid. I recommended they look at your vid and reach out. I’m glad they did. Cheers.
Hey Rod, If you really want to play with the transom height, there's a company that sells jack plates that you can adjust while under way. I think its called ontheflyjackplates. No wires, no hydraulics. Not sure if it would work on your transom, but its worth a look.
Good idea. Was thinking the same thing.
I work on boats for a living and I'm telling you that there's not a lot of difference between a 9.9 and a 20 as far as speed there is a big difference in power. However there is a big difference in speed between a 20 and a 25. I know it seems weird but it's due to the application class. You my friend need a 25hp and you will be getting the performance that you are wanting
I have to call bs. My 9.9 could not put my boat into plane. And my 15hp did it with the same prop
Solid advice. With a 15hp he should be very happy with 20-22kts WOT. I agree that he would get the speed and power he wants with a 25hp.
Boat is only rated for 20hp. And a 25hp motor is significantly heavier than the 20hp. You don’t know what you are talking about here.
Seems an issue for the boat manufacturer to fix rather than the owner having to modify & spend to fix the issue in the first place
Or get a short shaft…
Wonderful outboord motors, the Merc 15.
I am the first owner of a 2000 model.
24 years of loyal service and still a top speed of 43 km/h 27mph.
We have two solas props: 9 inch and a 10 inch,
both of stainless steel.
Keep experimenting,
everything is a competition on the water...
Hey Rod, thanks for this video. So I have the Truekit 4m Discovery and have done everything you have done with trying different props, having props cupped, raising the motor, and putting on a hydrofoil. All I can say is that as a standard set up (with the new alloy transom) it is a wet ride for the driver from all the water spraying back up at you from the motor. I also can confirm that raising the motor definitely makes for a dryer ride. If you could kindly post the details of the 9 pitch prop and where to get it from would be much appreciated as I’ll try it on mine too. Thanks mate. PT
Buy a real boat. You keep a blow up toy in the closet.
@@amwood7076 haha, we don’t all need blow up toys😜
Ditch the foil on the leg. Then try the props, whilst a also experimenting with the different trim angle holes. Only then should you fit the foil. It creates more drag than the rest of the leg put together, in order to give you lift in the stern. I have exact sam boat but with the Tohatsu m9.9.
Rod, this type of prop and engine height "tuning" really needs the addition of an tachometer. Without knowing engine RPM's amongst everything else it's like fumbling around in the dark. Additionally, engine weight is somthing to consider if you are comparing engine heights of different engines on the same boat.
I have a 16 ft fiber glass skiff with a 40 hp. I tried a couple of different props and a hydrofoil. Ditched em all and stuck with the manufacturers recommended prop.
Hydrofoil will get you nose down quicker at the expense of increased top end. Bigger props will decrease your revs because the engine isn't set up for it.
Keep weight forward as much as practical to keep your nose down.
If you want more speed, bigger engine is your best bet.
most sibs rated for around 25hp max
Had an inflatable about the same length wit a 25hp on it. It flew! The 25 was a bit heavy but I wanted the speed, so the sacrifice.
Nice to see some prop experimenting. Glad you came to a result you are comfortable with. Really love that little catamaran dingy.
Good things happen to good people. Thanks Rod
Your trim tab should be level with your hull, it has nothing to do with how high or low your transom is. So transom height must be adjusted so your trim tabs is level with bottom of your hull. The higher pitched prop should be faster and also use less fuel. Hope it helps
Mate it needs a 50 like all the thundercats down the gold coast canals womping along :D
Nice work Rowan hes the go to man at getting the right props on boats to suit application !
3inch jack plate it would set back the motor and you can make it as high as would want 3 inch L bracket 3x3 aluminum thick . I did 10 ft boat 30hp Johnson 54mph 15 pitch prop 😆sick fast 1 person baat🙋🇺🇸
I wouldn't be going with the prop for top speed. It's the one with most torque that you need. When loaded and not in ideal conditions you wont be going WOT, so you'll want the torque to push you through the chop, and keep you on the plane the best.
14:31 :) I have been enjoying the new Sassy stuff, last ep was pretty good. Always nice to see a frame dropped into your vids!
Hey rod there is a group of us over here in the southwest USA running inflatables in whitewater. I take delivery of my new 60hp tohatsu on the 17th, putting it on my 16' inflatable dib rescue boat.... one of these days we are going to have to get you out here to Utah to run some whitewater with us... have true kit send you a boat and I'll supply a motor for you to go smash up.
Hope theres fish so we can throw a lure in the whitewater when rafting lol
@@freedomfunwithjlbfriends7193 can definitely do some fishing on the runout on lake powell, walleye, bass, and stripper...
I do wonder how that prop would go without the foil on the engine. No doubt already mentioned by some how they will knock you top speed off a few clicks. All interesting stuff - im lovin it............Alex
Throw a 25 or 30 old merc or Yamaha. then you will be aired out and props will make a much bigger difference. wish we had more inflatable cats here in America. Look into a on the fly jack plate. If you dont mind holes in transom you can install a kicker plate as setback and get motor out of the dirty wash
I've really enjoyed this search for excellence and never thought of props before.
It must be the insight into you.
Thanks for it.
And "props" to Oz Propellers for piling in and extending the search.
Dude, you need to put a jackplate on to push the motor further back and away from the boat, then you can run the motor higher. In doing this, you will get more bow lift, which means more speed. Then, put the motor in a higher trim setting. It will plane slower, but you will get more speed by far. Try it and play with the best position you won't regret doing that. You will get more speed in doing these things than you will have in this video, playing with the props. That being said, you should still use the prop that worked best for you. Props are still very important, too.
There comes a point of diminished return between HP and drag. Go for what feels and handles best. Looks like you hit on it. Really the original prop wasn't all that bad though.
I think the limiting factor now is the shape of the hull, the amount of drag is limiting the speed. I think raised it even higher, might need an adapter plate for the transom.
It’s a catermaran, only the two sponsons touch. Far more drag efficient than a a traditional V or a flat floor sib.
Have a 30hp 2 stroke merc on my 330 Disco. Have seen 68kph with a powertech stainless prop, yet to raise the engine. Feels pretty sketchy wide open, wouldn’t want to go much quicker!
That's a huge weight increase! Any issues?
Stubbie coolers are a nice touch
What happened to yr live stream the other day i cant see it anymore, says its a private video now.
My question as well
Probably poor resolution. I had to stop watching it, it was like looking through foggy goggles the entire video.
Had this issue with the bris boat mini cat 3.2m but it was only a $1200 boat and good weekend project to learn what influences the boats dynamics. End with 150mm raise and a ozprops foil on a 2015 tohatsu 9.8hp 4 stroke
What was your top speed?
Just thinking Rod. In open sea with chop and swells you can only go so fast anyway. Think safe my friend you have a family and a you tube family. I’d miss you my man!
A couple of things to think about is more revs = more fuel and how much fuel did you have on board from the first prop to the last? Was there 10 liters used by the time you tried the last one?
Still advise you to try a 4 blade 9" ....will give you more punch off the line and maintain the top end....more punch off the mark for bar crossing and off the beach....👍
Loving the content, Rod! This technical stuff is a bit over my head, but I like watching your process of figuring things out. I hope you and yours are doing well and I can't wait for the next video!
Saturday morning sorted! Thanks Rod
🤘🤘
Love watching the process Rod. I remember you hitting 40 on the old boat, maybe 42. Am I mistaken?
Maybe you should lay flat on the boat floor.....lol... j/k.
Great video very interesting to see how different pitch propellers act 🤔😎👍🏻🇬🇧
This is a great video but a better advert. Well deserved for the business man here, everyone is happy
Now, you can also add a Stabilizer fin to your outboard, that minimize cavitation, and creates a tunnel of water, also lower your nose and increase speed!!
When your getting on a plane, the engine may seem to rev a lot but the boat stuggles to get up on the plane, you could have cavitation ventilation issue. And from what I can see from the aluminum prop with paint missing. It's a tall tail sign of exactly that.
Power saws with bare feet like a boss!!!! Love it Rod!
Awesome stuff! If I might add a thought: it looks like the horizontal plate on the leading edge of your motor is designed to keep the spray down. I'm guessing this plate is becoming ineffective at higher speeds, causing the motor to throw about 10 kilos of water per second into the air rather than putting that momentum into your forward movement. Might be something that needs attention. Keep posting dude your content rocks!
It's a tender, not a fast boat design by any stretch🤣 An alluminium flat hull dinghy would leave it for dead
Still like boat tests. The disco community needs it
Hi Rod....just passing along an experience I had when I bought a new prop for my 30 hp Merc 4 stroke. The box that the prop came in (Merc factory stock prop) said to torque the nut down to 45-50 ft-lbs of torque. I did this and the prop was so over-tightened that I almost couldn't turn it by hand. The owners manual said to torque it down to 13 ft-lbs. I called Mercury customers support folks in Wisconsin, and they said to follow the manual and NOT what was printed on the box. I almost destroyed my lower unit by torqueing it to the value printed on the box. Also make sure the torque washer is facing the correct direction...mine is tapered on one side.
Nearly any outboard boat will benefit from a jackplate and foil, permatrim, compression plate. The plate should be out of the water when running on plane. You should be able to get that motor 3 or 4in/10cm higher without any problems with the jackplate. Love your videos Rod always look forward to them!!!!
This was good... Now I can't wait for your next island or fishing adventure... Cheers✌️🍻🎣
I love these videos because I know it's just a teaser for like you just getting ready for some insane content coming up! But still this and love the fact that people are noticing you and giving you stuff to review!
The tests are fo course important. If I would live there and there would be a guy driving up and down at 6am...I think I would make sure that there is a hole in the boat ;)
Hey cause of you lift it up straighter it will proform better for you on that boat by using A plastic barrel type plastic to make your boat transom shim wedge plates out of way easier to. On the way cheap to for your builds.
So lucky to be able to test all those products and find the sweet spot Rod! Good video mate.
The motor is still too deep, I’d set the anti cavitation plate about 25mm above the bottom of the boat. Watch the telltale to make sure the motor isn’t starving for cooling water.
Hi rod just wanted to say this brings good memories for me I have been in a Zapkat race boat which was very similar but it had a 50hp tohatsu 2stroke on the back I was up front switching sides at each turn, what an absolute thrill it was the amount of GeForce on a corner was fantastic I hope to get my self a zapkat at some point in life lol
And with the racing props you can bring the planing plate up yet a centimeter or three to get just a smidge off air to the prop.
Witch means you need to ad at least 1/4 more of width of tilt to the output shaft also for A straighter free flow.& Thurs output torche to.
Gday Rod,I have the aquamarina 335 i mentioned to you motor height and trim and i also played with different props and i think that the inflateable dont hold their hull shape at speed and the only way to overcome it is more horsepower hence you getting similar max speeds after each change.A solid hull would perform better because it doesnt change shape.So like you i improved the bottom end but didnt change the top end much.As always the answer to everything is more horsepower :)
motor is still low. u know because of the splashing on the motor case. raising it more will improve the performance. i think this motor is long shaft and the needed is short shaft for this rib.
Super interesting vid! I’m also a discovery owner and have been experimenting with similar things, wish I saw this video a year ago before I started!!
The boat is totally fine as is, but as you dig in you can definitely get more out of them and that’s honestly half the fun sometimes! Keep it up mate.
Everything I know about boats is pretty much from this channel , I’ve always wanted a boat just never had the spare cash . I like learning about it, on that note. Can someone explain what “dirty water” is to me pleaseeee! Thank you for the video !
The fancy props won't do anything. Waste of money.
The bottleneck is the boats soft hull.
Remove the dropstitch floor, fabrcate a hardwood floor, and install a hydrofin on the outboard. Then watch the speed increase 2x.
Time to load up plenty of extra fuel, a cooler, camping and fishing gear, and head out to sea to explore some barrier islands or atolls.
I'm thinking about selling my boat for one of these. So musch you can do with it. won't even need a boat ramp. Fantastic video mate. Great to watch 👌
Good video, seems that the Mercury Engineers do know something about specifying prop pitch for their motors.
Stainless steel prop looked amazing on boat
I always say, the manufacturer has been doing this for many many years, they will do what is best for the motor performance. Watch out for lifting your motor too high on the transom, you might end up with your motor at the bottom of the lake. If you want to lift the motor higher, consider having the transom lifted by a professional. Have you got a long shaft motor, if so maybe you can try a shorter shaft motor.
Fuuuck man we got it 9 pitch 10 pitch. Speed up!
Get you a fence post on that handle of this tiller and sit on the front of the boat
Still to low Rod. Ideally when your on plain there wouldnt be any water on too of the anti ventilation plate. Im not sure you can get it high enough without some plate bolted to that transom. If you could get it high enough the 11 might be the ticket. In the end the fuel saving is worth doing all this alone
I think they make small boat adjustable jack plates. Might look into that if its something youre gonna stick with
Hey rod I would love to see some more videos on misty I really enjoyed those videos
y dear friend, just a piece of advice, and I have been around boats and outboards for a wile: Use a Jack-Plate to raise the motor, any other "invention" will com on detriment of your brand new boat
thanks for sharing. i wonder if the highest-grade petrol might help with the speed?
For every inch of pitch there is about 200 rpm difference, maybe try an adjustable jack plate for an off set from the transom of 4 to 6 inches and you can set the engine even higher for less drag.
Wicked, Rod.
Props, everytime.
Wicked video, my immediate thoughts would be to raise that engine just slightly again. See what happens
Try play with motor trim too get it to the limit before bow starts to bounce in the water, less drag, faster boat also I’ve always gone with the cavitation plate should be level with the lowest part of the boat it also stops the spray same as how a long shaft motor will be slower then a short shaft that lines up properly
I think you need to throw that planning plate you have bolted on the leg of your motor, they can help to pop you up out of the water but the problem is you can't trim your motor once you are on the plane because you have a fixed trim, also you may want to look not so much at the height of your motor, you might actually need to move your motor back with extra blocks it possibly could be to close to the bottom of your boat causing it to cavitate.
Will you run a prop guard? I heard if you hit anything stainless wont bend so it damages the shaft etc of the motor if you hit something.
Sounds like a good idea, safer too.
Stainless does bend mate, got a stainless prop at home. However you will be right will stuff the shaft up
No prop guard, they are like an underwater parachute. Huge amount of drag good for safety of humans and aquatic animals, like Mr Puffer fish. But very bad for speed and fuel economy.
As making shim wedge plates for raising it up with I say about 1/4 inch up.
Hello, I have the same transom on my true kit 280, I drilled out the rivets and raised the plastic piece and re riveted. I have my motor height set so that the round clamp is just slightly above the transom but the center is still on it.
If you tap the speed on naviocs app it will make it bigger and show tenths of a km
Bud, those voices breaks had me in stitches 😂.
You should try an over the hub prop. Surely you can find one that allows exhaust to go over instead of through the hub. If that hull is going fast enough to get lift from the air under it then maybe go with a clever style blade instead of round ear type. A chopper or clever should be available because of the little kneel down hydroplane guys still racing these little motors
Great video but the motor is still way to low
No water should be coming over the top of the cavitation plate at full throttle 👍
I agree with you. There is too much motor still underwater creating drag thus you will not see any speed difference between the props.
Someone told me I should check you out and he thought we’d get along. I’d have to agree 100%.
Careful with those stainless props though! They’re unforgiving and can damage the lower unit if you hit anything. They definitely push water a lot better though.
Welcome to the channel mate🤙
Love the content as always and it's really awesome to hear about that kind of costumer service. LOL Big props to Oz Props for being one of the good ones!
Goes pretty fast. Is that a short shaft or long?
Hmmm… was that a subliminal badoing badoing at 14:32??
Looks like you have a long shaft motor on a short shaft boat the ride plate on the motor should be level with the lowest point on your hull. I have a Jack plate on my speed boat that allows me to adjust the motor up a d down vertically. Then you can try prop pitch for top speed.
You can hear a lot of drag. That motor is sitting way low. But there’s a reason for that lower transom
The Lil rigs screaming 🤣
Surely the maximum hull speed would be a deciding factor, even as you say, a catamaran hull works differently!
Without reading through all the comments to see if is mentioned, be careful with the SS prop in rocky, hard bottom areas. You can easily damage gears or shafts if you hit something. The alloy props bend, SS doesn’t. Ask me how I know. A very expensive repair for me.
Same boat with 9.9 yamaha two stroke I get the same speed with two people . This year I upgraded the outboard to 15 hp
Try tilting up just A little bit more than we're it's set at now by shim wedging it up.
Good effort thanks stainless props may help slightly but they don't give if hit object s and can result in gearbox damage have a four blade prop on 15 Yamaha 3 m polycraft is slow er to plan but has a really.good mid range tops 24 kts I've found transom height adj is key to good handling try 5 mm shims of ply help find sweet spot easy on day slide another one in. Pay to get little dry bag for keys modern ones expensive to replace n don't like salt thanks again for doing this testing n share little boats often left out well done
finally you made 20 knots😁
I think your limiting factor is the potential hull speed. Ron.
The wet surface on a cat results in more drag than a similar sized mono Resulting in more HP req’d
Thundercats are an exception, when they plane at 100km/hr the hulls are almost out of the water!
My single engined Ali cat has a 90hp outboard, if I replaced it with 110hp there would be almost no difference in top speed because of this drag
I’ve just watched your motor adjustments with interest. With regards to maximum speed, correct me if I’m wrong and if memory serves me correctly, the maximum speed of a boat is proportional to its waterline length. Hence as you older craft had a longer waterline, then it would be a little quicker at max engine revs.
Plus there maybe subtle differences in the stern shaping and design between your previous and current boats that’s causing the dirty water conditions and therefore you may not be able to improve the situation in this area.