Aluminium Boats

[beau]

I have designed and supervised the construction of a 12 meter aluminium Trimaran.
It was built by a professional boat builder and also painted by professionals. No problems at all. I would highly recommend Aluminium. Very fast to build and cheaper than fiberglass. It is nosiy and you MUST insulate.

[cathyoz]

Originally Posted by beau

I have designed and supervised the construction of a 12 meter aluminium Trimaran.
It was built by a professional boat builder and also painted by professionals. No problems at all. I would highly recommend Aluminium. Very fast to build and cheaper than fiberglass. It is nosiy and you MUST insulate.

cheaper than Fiberglass?
witch Tri , and where did you get it build , here in Oz ?

[beau]

reply to Cathyoz.
The boat is a 12 meter trimaran. It is discussed in this forum under multihulls/beaus' boat have a look.

It is designed as a fast displacement motor/sail trimaran and will also fit inside a 40 ft shipping container for shipping overseas.The floats fold in for berthing in a MUCH cheaper monohull marina berth.

The design disk was sent to Smorgons aluminium and a week later all the pieces were delivered all pre cut. It was just a case of tack welding everything together, prior to final welding. The hull was complete in three weeks.
I really would not consider the project DIY until the aluminium part is finished. I watched other builders in the yard spend two years "fiberglassing" when the aluminium trimaran was completed in 4 months fully fitted out.The painting must also be done by a professional

I have built in fiberglass before and would now only consider aluminium. I would also expect the resale value to be higher because the aluminium is a quality product (no osmosis) and professionally built will also help.
I am in Brisbane if you want to have a look.

[cathyoz]

Originally Posted by beau

reply to Cathyoz.

I am in Brisbane if you want to have a look.

very interresting
sure i will love to have a look, if the trimaran is in Brisbane
when i was in Paris last december at the boat show , i spend all my time there comparing different folding trimaran.
i must go to Brisbane on the 13 for the doctor
if you have some picture, could you send some to me , i don't know how to find the topic on forum...
thank you
seagipsy_cath@hotmail.com

[David M]

Another aspect of an aluminum hull is that no mold is necessary. What this means is that larger custom designs can be made without the necessity of a mold, therefore saving the cost of making a mold.

[beau]

I agree david,
I used to manufacture a 29 ft Trimaran in fiberglass, but everybody wanted the design, shorter or longer or more head height.

With Aluminium you can modify or custom build very easily using a Naval architect, who can use computer generated programs to quickly come up with the structural details and have it sent to a cnc cutting facility.

I was originally going to build it (weld it) myself but after seeing professionals in action I really don't think it is a DIY project. Plus they are so quick and you do have a professionally built boat.

I used flat panels(no curves) and I am very happy with the finish, however you must use a minimum of 4mm thickness if you want a smooth hull.
I also believe Aluminium is relatively cheap in Australia (we produce most of it) we have quite a large aluminium boat building industry.

[David M]

Hey beau!
Yes, Australia has built some magnificent commercial aluminum vessels.

I agree as well about not doing it yourself. Aluminum welding is a real art form and a science as well. Here in the US, the Coast Guard requires aluminum welders to be CG certified to weld on new vessels that will be carrying passengers for hire.

David

[over40pirate]

My wife owned and lived on a 38' aluminum sailboat for over 15 years. I lived on the boat for 4 years with her, before we sold it.
She told me that while racing another boat smashed into the stern quarter, and just put a dent in it. The other glass boat wasn't as lucky. The repair required cutting out a section and welding in a patch.
For offshore sailing there is a nice safety feature with aluminum. Although, I guess it depends on how and who built it. Her boat was built by Minnifords, and was built for ocean racing, in the Admirals Cup. It was built strong.
Before we sold the boat, we had her hauled out for storage, and there was a bit of corrosion on the skeg for the prop shaft, and some where bottom paint had come off. The boat had been in a fresh water Channel for 15 years, and the last haulout and botton job was about 6-7 years before we hauled it out.

I think if we were to keep the boat and cruise on her, I would want to keep a close look at the bottom, for any signs of bottom paint coming off.
Maybe even hauling every other year just to inspect the bottom.

She and her Ex insulated the interior to cut down on condinsation, before they had an interior put in the boat.

Here is a picture of Lightnin' before we sold her.

The part of the boat I liked the best wasn't made of aluminum. It was the sheet winches. 3 speed titanium beauties, that were originally mounted on the cabin top.

[rgm.nz]

Steve
Don`t know if you got all the answers re bottom paint for aluminum but I can tell you
what works on my current boat & works on many fishboats ,workboats . First nothing
will stick without sandblasting the alloy . It is important to stick with one product line ,
their system in other words . I only use Ameron which in NZ is sold under a different
name , don`t recall what . The Dashews use it and it is on their website .
1st - two coats of Dimecote 302 Zinc Primer on all fresh blasted bare aluminum
2nd - two coats min Ameron 235 Primer , alternate colors to ensure coverage
3rd - two coats Ameron 214 antifouling , a commercial product . This is a hard paint .
Ameron also makes ablative & other antifoulings . Yes they have copper in
them but using a good system works , 12 years on this boat . You effectively
turn the bottom into one big zinc anode by this method . Hope this helps .
RGM

[Steve Pope]

rgm.nz thanks for the info on Ameron, I will do some research on it. I am about to redo the hull with Trilux33, I have used internationals basic Trilux which gives me around a year using 3 coats plus xtra on edge surfaces. I'm hoping Trilux33 will last longer especially as it costs at least double of Trilux.
When I bought the boat I found a product called "Inversalu" on the website of one of the French Aluminium yacht builder that spoke highly of it but have been unable to source it or in fact contact anyone who has used it. Perhaps the trouble is being on the otherside of the world! Inversalu was a zinc rich product that did the same as you say Ameron does, turning the hull into one big annode. Cheers, Steve.

[Factor]

Australia has a number of excellent aluminium cat builders designers - Peter Kerr, Owen Easton, Tim Mumby. Some really nice boats. An owner of one has developed his own antifoul with chilli powder mixed in and gets similar protection to me with me using Jotun Sea Guardian.

[rgm.nz]

Steve I forgot to mention that the zinc primer & 235 primer are both 2 part epoxy type
products so they are tough once on the alloy . Sandblasting or many hrs holding a
grinder over your head is the only way to remove it . Sanding between coats is not
necessary if you follow the instructions and apply each coat within the timeframe
allowed . I looked into Trilux 33 and spoke to alloy boat owners who`ve tried it . Very
expensive and does not last long is what I kept hearing . Ameron is cheaper , lasts
longer and has a long track record . Navy uses it and all commercial boat yards in
this area stock it . I got the 3 step info from the Ameron rep in this area . Bottom paint is becoming more of a challenge all the time . If I had a huge boat I might carry
a 10 yr supply aboard . Good luck .
RGM

[Steve Pope]

RGM. I have looked on the internet and there are quite a few suppliers here, apparently is is made under licence, the head office is in Auckland so I will pay them a visit next time I am down there, It may be OK to apply over the trilux that is on there at present, i'm sure they will be able to advise. Thanks.

[Kev]

it's an old thread, but am interested in getting additionnal info on this Ameron paint !

I am currently using Trilux 33 "professionnal" from International, but it's quite expensive.

Anyone would have the ref. of this Ameron coating for aluminum hulls ?
Does it perform/last well in warm waters ?

Many thanks, Kev

[MichaelC]

I had a Colvin aluminum schooner. Owned and sailed her for ten years. the aluminum was the easiest maintenance I have ever had on a boat - wood, glass, aluminum. The boat had 6061 frames and longitudinals such that the largest opening was 10" X 24", then the 3/16 5000 series plate was welded on, lapstraked at the bow. Sand swept before painting, I used three coats of Interlux Tank Guard epoxy undercoat, the last coat being covered with color while it was tacky. the paint was put on in my yard by drunk neighbors with rollers. Ten years later it was still perfect. I hit a log raft in the middle of the night while under full sail. No damage to the boat. I hit a dock moving too fast so hard it sheared the ss bolts on one chainplate. Aluminum did not deflect. I ran over a reef at the entrance to Nawiliwili on Kauai. No damage. While in the Sound I put her ashore to clean the bottom twice a year. Just pulled her to shore and waited for the tide to go out. When I sold her there was not a smidgen wrong with the hull or paint [or anything else]. Aluminum problems? Bad preparation. Period. I am beginning a 32' hard chine gaff cutter. I WISH I could afford the aluminum. I would do it in a heart beat. The same story could be told by anyone with an aluminum boat that was built to Colvin standards and prepped as he says. Be careful of badly copied 'Colvin' boats. Always check with himself to make sure the boat is really built to his design and standards. I have seen some atrocities out there where the owner claimed they were Colvin designs.