Replacing our ROTTEN Bulkhead
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- čas přidán 3. 02. 2023
- In last week's post we showed how we made carbon fibre chainplates for Paikea. The chainplate arrangement was originally a stainless steel strap with a backing plate bolted through the bulkhead. The bulkhead was a eglass/plywood construction that had lasted more than 30 years but now the plywood core had rotted away and only the glass was left to hold the chainplates in place. As a result, the bolts were slowly moving upwards towards the deck and allowing the chainplate move upwards also. For more information check out our blog - youngbarnacles.com/?p=5436
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Thanks for the detailed explanation, things have come on a lot with composite technology since I last built a boat. I am with you on liners and access to fittings and systems, boatbuilding started to lose it's way in the 60's with the advent of production fibreglass boats being churned out and much of the fit out being done before the deck was installed, don't worry about the poor guys who have to fix anything in the future as long as it looks good.
There is a lot of pressure from buyers (especially people from a non boating background) who want to buy a boat that looks and feels like an apartment. Manufacturers have the constant pressure from buyers to produce these boats with all the extra features instead of sticking to building a good sailing boat. There are some pretty tight margins in boat manufacturing and if the market wants a condomaran you've got to be a pretty confident business operator to stick to your guns and produce something that is not.
Well said, so true these days! I'm lucky enough to have an Australian 1980 Endeavour 26 monohull. New buyers back then fitted out the cabin themselves lol, luckily with mine it wasn't complicated at all & I can easily access everything although EVERYTHING is old school 10mm marine plywood. Still in perfect condition.
Love your videos too, I'm about to start using carbon fibre & epoxy as well. Aiming to replace all the plywood with foam + epoxy + glass.
FYI seriously, keep up the good work on the videos! Awesome stuff, you should really have ALOT more view. Cheers 😊
Excellent explanation thanks 🙏
You are welcome
Lots of work replacing the liners and weight. I like the K.I.S.S. principle and the points you raised about accessibility. Another great vid thanks crew
Cheers Rick. Yes lots of work but it will be worth it in the end
love your videos - really interesting to hear a composite expert covering this sort of stuff. Please keep making them, I expect you're going to gain a massive following over time. Why not make a video about the Lagoon bulkhead issue?
The Lagoons bulkhead problem has been explained plenty good already on Parlay Revival, albeit by a guy with far less advanced knowledge about composite structures. Still, for CZcams that’s arguably good enough. The explanations in this video are also very far from approaching the limits of his knowledge… The bigger challenge to get it simple enough, by leaving out all the important and nerdy details. (I’m also experienced with this stuff.)
Edit: It’s important to not believe that this bulkhead issue is a Lagoon problem. It certainly isn’t. It’s a problem of poor engineering and poor material choice (wood), and then hiding it behind innerliners etc. These problems we can find on close to all production boats, including monohulls. Building it far better (still not perfect) wouldn’t cost more, but the wharfs don’t want the boats to last a too long time. Just as with cars and houses. They are seen as consumables. That mentality is the main reason we humans are filling the planet with garbage.
@@SteinVarjord All good points - I had thought, a bit cynically, it would be a good way to stimulate clicks and followers.
@@SteinVarjord Do you happen to know if :Lagoon have changed or modified their design on boats currently being produced to overcome the problem idetified or do they continue as before.?
Thank you for the excellent follow-up! I enjoy the engineering insights!
The best sailing channel by far these days! No invented drama, just real...cheers. Look forward to running into you guys one day...
Cheers mate. Glad you like the videos. And definitely if you see us in the harbour come say hello 😃
Love and totally agree with removing the liners and having the sheek racer type aesthetic inside. Clean finish and painted not only for servicing and monitoring but maximising space and persuit of clean and basic to me screams all of what good sailboats should pursue 👌Love the Catana design bang for buck though! Also your work and looking forward to a walk around perhaps alongside ideas of upcoming project ideas as you go around? THANK YOU for sharing this and going to the effort to document for us!
Great video with super clear explanation. The sailing scenes with music at beginning and middle are very well done too. Awesome job!
Hey great video. Really love the full explanation on your repairs/upgrades. I have a Lagoon 440, hull #1. Boat has been around the world with previous owners. And--like many older production boats-- is in need of of reinforcement if I'm going to feel confident taking her around the world for a second time. There are some weak points that other 440 owners have recommended building up around where the bridge deck meets the hulls and now I'm thinking carbon fiber might even be a good choice there!
I have been looking into lagoon boats, there are many stories of delaminated beams and cracked bulkheads. Not the end of the world, but definitely worth pulling the trim off your bulkheads for inspection.
@@taylorhickman84 Hey just saw this. They aren't just stories. I was at Zimmerman boat yard watching them pull out over 20 Lagoon 450s for bulkhead reinforcement. Although Lagoon has admitted to there being a problem and fixing it. Leopard and FP have their own problems, but you rarely hear about them.
These production boats are built to be constructed QUICKLY. If they can glue instead of tab, and that saves $10k in labor per boat then they're going to do it. Why? So they can sell it at a good price point.
A lot of people seem to forget that and tell you to go buy some boat that's 4x the price. Why does it cost 4x more? Because they spent 4x longer building it!
Thanks for doing this follow up video, very informative. The one thing I look at is the amount of glass overlapping the new to old bulkhead, I would have thought you’d need to go a lot farther than 5-6 inches but makes sense when you see the whole picture. Good luck with the other side 👍🏻
Here you are again, haha. It is very cool to see how the "appear to be" dinky little 526 chainplates are compared to the 482 external bolt on ones. It's great to know it is as good as it gets.
great video
I did comment on the first video and thanks for the detailed video detailing the structure integration. Super cool! Still, it seems like the e-glass load spreading should have gone further down onto the old bulkhead and further inboard on the original bulkhead. I am not an expert just my old engineering eyeballs but you have proven it works.
For sure! Every day is a lesson.
The limiting factor in transfer of load across a lap joint is the peel strength of the epoxy. My composites engineer friend did the calc when building the 40' race boat. The laps on the skins of the hull were 2". (triax e-glass) Nice to have someone who can do the math.
Love your edumacational videos, very very informative 👍
So great explained💯
awesome
A butt tonne of safety factor and a lot of work. Could that method replace deck cleats?
Super explanation of your design and build Shane. Bet the pucker factor was substantial getting the hull out of the water. Yeah no probs on the GB68 but the Catana ? not so much. Seems like a lot of the boats out of France with ply coach house bulkheads have issues distributing load when they're a bit older.
I think it's frign awesome. Love to get rid of my weird setup chain plates.
Excelente!
Really nice! Really nice. One more question. Why carbon at the "tips". Can you make the same job in e-glass or glass. Adding more material. To get rid of stainless.
When you say tips are you referring to the part of the chainplate that is on the deck? You can make chainplates using eglass you just have to add more material to get the correct strength you require. The stainless steel sleeve is the interface between the metal pin and the composite chainplate and is required regardless of the material used to make the chainplate..
@@youngbarnacles THX for info. Yes tips / part of chainplate above the deck (carbon part in your case).
Glad you admitted to using a shocking amt of carbon; my math says you could’ve done it with E glass uni just fine. What was your final layup on the bulkhead infill and overlap?
How did you calculate the layups (material and resin) you used to build the chainplate as well as the choices of bidirectional e-glass you used to bond it in-place? I see that you based the design off of the materials and resin you had on-hand, but how did you figure out how much to use, what shape and dimensions were required to take the load? I am a bit new to your channel, so please excuse this question if it is already answered somewhere on your website or on a previous video.
I've got 20+ years of composite and engineering experience to draw upon 😁 If you were planning a project like this yourself we do offer consultancy services. It is definitely not a slap it together and hope for the best situation.👍
czcams.com/video/yvvyDdgUrrQ/video.html
Really nice🏋🏻♀️🤟🏋🏻♀️, thanks.. could you talk about the problem With mixing carbon With aluminium , and work arounds, thanks🤗
Do you have a particular application you are thinking about?
@@youngbarnacles We are thinking of getting help with building an Explo cat, right now we want a cat where the hull is aluminum and the rest in carbon. At this stage, it's just general thoughts, before we contact possible producers.. We saw that you had problems with the alu-carbon mix..
Sounds like a cool project. We have experience with expedition yachts that have carbon masts/bow sprits/booms etc. It can definitely work. If you want to discuss further send us an email admin@youngbarnacles.com 👍👍
Did you have to calculate area need for the shear strength to exceed the force caused by the mast and sails? I guess I’m asking how you calculated how large the carbon fiber component needed to be?
Typically you use the breaking strength of the shroud wire attached as the design load. Then add a safety factor to that number. Because shroud loads on cruising boats are ~20% of the breaking strength of the wire, you are already at a ~5:1 safety factor. Actual safety factory used appears to be a METRIC butt tonne
@@evangatehouse5650 Thanks....I didn't even think to use the published wire breaking strength.
This might explain why surface area and friction is better than bolts. czcams.com/video/AX_lCOjLCTo/video.html
spot on! that's the general idea! thanks for vid link too. Kids love the Mythbusters. Might put this link on our open forum if anyone wants to discuss composite chainplate stuff
youngbarnacles.com/forums/topic/composite-chainplates/
Not very impressed that the standard Catana ply bulkhead has a butt join so close to the chain plate area and the area where major twisting moments between the hulls are experienced.
people have also used unidirectional fibreglass instead of carbon, I've seen an old video of this done on a Crowther 150 (?) design -? czcams.com/video/qHbFuvW4lpY/video.html
your thoughts ?
yes people use unidirectional fibreglass rather than carbon fibre for chainplates. This was definitely the case for the Schionning catamarans in Australia. The only difference being you will need more eglass fibre to get the strength you need. (In the video link you sent Mike used carbon for his chainplates and eglass for his little pad eyes)
youngbarnacles.com/forums/topic/composite-chainplates/
@@youngbarnacles thanks for your reply, what I particularly like is avoiding the SS maintenance concerns, , and the elimination of deck water penetration issues
Absolutely