Which material really is the best for building a world cruising yacht? Metal or GRP?
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- เผยแพร่เมื่อ 29 ก.ย. 2024
- Which material really is the best for building a world cruising yacht?
In this episode Dick Beaumont of Kraken and Dick Durham discuss which is the best material for building a world cruising yacht, Metal or GRP?
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Thanks for watching!
I would like to slightly expand on the question of GRP for high latitude sailing. Because when the day comes, I suspect I will be chasing more snow than turquoise lagoons. An ideal world cruiser would allow me to chase the winters on snowy coastal mountains. Which is probably the opposite of what 99% of cruisers want to do so catering for this market section is not wise to begin with :D But I still want to ask and learn.
So durability is a major concern. But I fully trust that both aluminium and GRP can be strong enough for practical purposes, provided it's designed for the use case and no corners are cut. Isolation transformers and stray current detectors help with other shortcomings of aluminium, and I haven't heard too many complaints from owners of modern alloy yachts. But where I would like to hear more about the choices of Kraken is insulation. So if I'd compare, say Kraken 50 (or preferably the 44 ;) ) to another boat I really like, the boreal 44. One thing that pops out is 50 mm insulation below waterline, 80 mm above waterline. Throw in a gravity fed diesel heater that consumes no electricity and it truly is cozy place to hold out a blizzard. Now, solid GRP construction below waterline and while thick for GRP laminate above, my first instinct is that this wouldnt be ideal for extended stays in 3 degree seas with air temperatures regularly on the freezing side? Sounds like condensation and heat loss. I'm currently on a swedish built foam cored (above waterline) GRP boat. Naturally, a smaller boat, and laminate is nowehere Kraken thickness, but even with insulation foam added where possible, it's far from ideal. Other point of concern would be the big windows: while I love, absolutely love, the triple glassing on the Kraken, I doubt it's spaced with air in between for insulation?
Sorry its not good enough. We need destructive testing. Thankyou.
Relax!
Aluminium is better))
I still believe in Jack Chrysler's promise of marine titanium.
For cruising in high latitudes only need to look at what the commercial yacht companies are using…. bare Aluminium is the preferred material. It’s ductile and maintenance free… and for non commercial high latitude sailing many, if not the majority, of the boats encountered are Boréal, KM Bestevaer and Garcia which are all Aluminium builders
Hi Mike
Actually commercial boats use Ally because it's a lot cheaper than building a high impact large vessel from composites. They don't make the bottoms of modern combat tanks from aluminium, they make them from composites. Maintenance free?? Aluminium and salt water?think Alka-Setzer !
If Aramid fibres are used in the composition engineered layup at the potential collision areas it will have far greater impact resistance than Aluminium.
Thermal insulation and condensation is another important consideration. A well laid up composite structure with an integral structural foam layer, bonded on top of the hull lay up inside, is far superior. The caveat to this is that the foam layer should be additional too, not in place of, the outer composite FRP hull lay up. Meaning that you still retain the optimum hull lay up then you add a foam layer then bond that in.
Yacht builders tend to develop their construction from what they know, rather than analysing what is the best material for a given application, just because everyone does it, it doesn't make it right.
Dick B KY
Someone tell Jimmy Cornel and Pete Goss that they don't know what they're talking about. All these trips to the Arctic with aluminum boats didn't teach them anything.
I’m not saying Jimmy Cornell and Pete Goss they don’t know what they are talking about I’m saying the technology now available in GRP composites presents a better alternative.
Do I hear some cognitive dissonance creeping in here?
Except Cornell and Goss didn't choose aluminum 50 years ago but within the last decade. GRP technology hasn't changed THAT much in the last few years. Aluminum is more than 4 times stronger, so unless you're going to build a grp hull that's 5 times thicker, it's not going to be equivalent, reinforced or not. And then there's the issue of plasticity: when aluminum gets hit it bends. When GRP gets hit it breaks. And that makes a difference. I think it would be better to just come out and say what Sirius yachts put on their website, which is that yes, aluminum is stronger, but GRP is strong enough for most uses unless you really plan on going to the arctic (and maybe even then), and therfore why deal with the hustle of worrying about aluminum's galvanic corrosion or getting paint to stick when the intended use does not necessitate it. You can't do that because your marketing is based on the premise that Kraken makes no compromises, which is simply not true cause every choice, whether it's material or a fixed keel vs centerboard, has pros and cons and much depends on intended use. I say all this because I respect you as a sailor, we were both sea scouts (and hence brothers) and I am afraid l that your overkill claims (and those of your cult like followers on TH-cam) have the opposite effect from that intended. Cheers
@@constantinealexandrakisThe opinion expressed in this vid was well informed and well considered, and I must say, well explaned too! I personally agree that a properly laid-up thick GRP with aramid/kevlar reinforcement is preferable over aluminum for a hull.
As regarding the sailor names you dropped- that reference to Pete Goss is strange as he went from an aluminum Garcia 54 to a costal plywood-made butt-ugly shoal-draft monstrosity that only its creator-himself can love! He also famostly voiced some wacko opinions outside of mainsteam - for example him being against in-mast furling...
The weirdness of such an opinion (besides limiting one to a thirty-footer) was demonstrated by a somewhat recent death of a German sailing couple on their CNB 60-footer in the Atlantic during a storm, as it was posited by the investigators that it was their in-boom furling system that effectively got them killed: - The boom has to be very horizontal for boom furling to work properly while the in-boom system makes ot much heavier and therefore dangerous when it is swinging! When the arrestor ropes snapped during storm, it was this extra heavy fast-swinging boom that delivered the killing blows to the heads that killed both sailors. It was saif that if their yacht had an in-mast furling, that accident may not have happened! Yet your Pete Goss is so against in-mast furling that it makes it difficult to take his other opinions seriously... Notably, Mr. Rassy swears by in-mast furling to the extent that every Hallberg Rassy models have to offer in-mast furling as an option or else he will not produce a yacht that is too big to have an in-mast furling...
Yes, good thick GRP with kevlar IS stronger than aluminum hull not to mention it being inert and not susceptible to "galvanic action" that renders a typical lifespan of an aluminum yacht at about twenty years! Even wondered where all the older aluminum boats have gone?? Yet, there are forty-year-old and older Najads, Rassies, Scanmars, Rustlers and other top-tier GRP-hulled boats abound, some still in condition akin to a new! So a simplistic preference for metal hull is somewhat childish, and as one becomes more aware of nuances concerning material lifespan, upkeep, chemical makeup and properties like material fatigue, GRP becomes ever more appealing...
And, please, no references to wacko weirdoes like Pete Goss- He is a known eccentric allright...
I have had a bare aluminum boat , there not as great as people think . They are a lot of work to keep paint on them and they look like concrete when they oxidize. I prefer GRP if done right . Totally agree with your opinions .
9-9-24. First of all this is a very good sailing Channel with very knowledgeable safety first yacht owners.
Metal or GRP. My comments source: Video from the Nikki and Jason Wynn-Gone with the Wynns You Tube Channel.
Here is what we have seen for ourselves via videos shot at the HH factory in Vietnam by the Wynns as their vessel, an all electric HH44OC hull #3 was being fabricated. Video that included some in-depth interviews with HH factory mgt, engineering, electrical staff and some local very skilled catamaran artisans regarding which material they know is best for world cruising and world class racing vessels. Bottom line. GRP, Carbon fiber and epoxy - hull and mast, same for Cat dagger boards.
Epoxy resin fiberglass 18 mm thick with aramide beats aluminium. Dent equals drag.
Wouldn't it be great of Kraken yachts made lifting centerboard/keel yachts? 🤔
Maybe, but at the cost of losing sail area. All centerboard sailboats have smaller masts because of the high center of gravity. The question is: what is the level of commitment to this solution?
Just curious - there been some news lately around Orcas attacking sailors and specifically the rudders in order to sink them. I assume the strong rudder with solid skeg in the Kraken would be quite impossible to destroy in the same fashion, but has there been any known such incidents..?
How about carbon fiber / epoxy instead of GRP? “Well laid up” of course :-)
Carbon fiber has bad impact behaviour, suffers from catastrophic failure which means it sheers apart completely if pushed past it's limits
Yes, hence the aramid layering, too.
Hi Guys
It's all about horses for courses. Carbon fibre/Epoxy is very strong and, if you're trying to produce a very light boat, it's a good solution, but.... a) it's very expensive and b) if your not trying to win races, why do you care about weight, within reason? In fact, if you're trying to create a yacht with a sea kindly motion the last thing you want is a light boat that's slamming and bouncing from wave to wave. When you have 6 or 8 muscled up racing crew doing 1 or 2 hour watches they can take an ocean voyage of 10 or 15 days of tough physical effort no problem but, taking off down the front of a big wave to get the boat planing is the last thing a husband and wife live aboard crew want.
Dick B KY
That’s a very legit point Dick!
Maybe also a good argument to look for a 1970-isch boat. Yes smaller rig but great looks and great sailors.
Greetings, Harry
@@richardbeaumont3650 Of course I don't want to slam and bounce but isn't it better to have the weight in the keel than in the hull/deck? It seems to me that *if the cost is acceptable* then one can make a faster, safer boat at a given weight by using CF for the hull/deck and putting the saved weight into the ballast.
Take with a grain of salt , nothing new about his boats cept they like most cost way more to buy than build
"Nothing New".
"Cost way more to buy than build"
We are witnessing an actual genius leaving his comments. The age of enlightenment is nigh.
A typical f/g lay up is almost exactly equal in weight and strength to an aluminum plate of the same thickness. Aluminum is stiffer. Don't forget the mast on your f/g boat is most likely aluminum.
Aluminium welds are only 60% the strength of alu plate, and there's far greater geometric freedom with GRP because it's only rigid once set up. You simply cannot lay up aluminium plate as thick as GRP in any kind of economical way. You can't triple-up 5mm plates and expect the result to be as strong as 15mm, because it won't be, it's not bonded throughout the entire structure like a GRP layup is.
Given equal thickness, I'd much rather hit a rock with a GRP hull. Not only will it fail later, it's failure mode can be less catastrophic than aluminium. GRP will fissure before it holes, aluminium will just hole. Fissures are far easier to patch than holes.
This may be the best material of all.
th-cam.com/video/vTfLY0Fcapo/w-d-xo.html
Hemp.
Boat would be SMOKING!!!🤣😂
Perhaps a bit off topic, but I've got got to ask why you fellows across the pond find it impossible to properly pronounce Aluminum?? ;)
Maybe why they invented the English language?
Note: everything else is accents.
it's pronounced correctly due to the spelling: aluminium and here at home it is aluminum
Is it spelled differently in Europe? I had no idea. I stand corrected then. Aluminium it is!! ;)@@GNLJshl69
One thing, you don't know much about steel. Nor maintenance nor performance.
Care to expand
What this man does not know about performance and maintenance you could write on the back of a stamp.
@@shane49276 No problem. By education Engineer corrosion/materials and was apprentice as wooden boat builder a looong time ago. Will be a bit too long ansver to tap on my mobile and perhaps to present here. If you have an e-mail I wil with pleassure return to you later tonight. Now I have to address som electrical issues.
You wish you knew 1% of what this man forgot
Dear svhulda,
Would appreciate if you could counter with arguments. Very willing to learn on how to preserve steel hulls/decks.
I have sailed a steel boat and consider to have some knowledge but always willing to learn.
Thanks, Harry