can you make a steel or aluminum cat? or tri?

[Lt.]

Is it possible? Or are they to heavy to use.

[Vasco]

Check out "Lammer Law and "Cuan Law", two of the biggest metal multi-hulls going.

[Sand crab]

Steel is a definate nono. Aluminum is OK over 50' otherwise it is too heavy. There's a steel tri for sale. It's only been 2 or 3 years and that may tell you something.

[David M]

There are plenty of commercial aluminum workboats under 50 feet in length. Aluminum has a nice strength to weight ratio, higher than fiberglass. With an aluminum boat, you don't have to have a mold to build it, which is advantageous if you want a custom hull. Electrolysis is not a problem if you do the right things.

[Dulcesuenos]

My own opinions are based on having had an aluminum workboat that was quite expensive when new and also having spoken to people who own a very expensive french yacht made of aluminum. It ends up cracking at weld points. And has horrific corrosion/ electrolysis issues when in salt water. I have seen one aluminum boat fall apart from the inside out as welds seemed to cascade fail from.one end to the next. I will never own another alum boat for use in salt water.

[Sand crab]

Here's that tri.
1993 Hellemann Holland Trimaran Sail Boat For Sale - www.yachtworld.com
Yapluka used to build very big aluminum cats. Prometa still does although smaller.

[Lt.]

Remember, multi hulls.

[Hud3]

This fellow built an aluminum tri himself, intending to sail it around the world...

The Tin Can Blog - David Vann's Epic Journey Around the World - Esquire

[Doodles]

There are several of these out cruising ...

Easton Cats: Homepage

Also, take a look here ...Lizard Yachts Home

[savoir]

Did that guy ever get out of California ? He left SF amidst great fanfare and then all went quiet.

[psneeld]

yes to both...those that say it will corrode, crack at the welds or is too heavy are both right and wrong.

if done correctly...both are OK to use for the average size or larger (would depend on design)....if done poorly (like FRP or wood) they can be nightmares.

do some further research and shy away from the "no you can't or shouldn't" comments...they are often proven wrong in these forums.

[waikikin]

Here's one thats quite successful, but a motor sailor charter vessel Carpe Diem,* ex strictly business,* 60' motorsailor Catamaran for 230 000 us$ only... Jeff.

[Factor]

Originally Posted by Sand crab

Steel is a definate nono. Aluminum is OK over 50' otherwise it is too heavy. There's a steel tri for sale. It's only been 2 or 3 years and that may tell you something.

Originally Posted by Doodles

There are several of these out cruising ...

Easton Cats: Homepage

Also, take a look here ...Lizard Yachts Home

Peter Kerr of Lizard Yachts and Owen Easton both do 13 metere approx boats that have logged thousands of sea miles. Great boats, I know a guy who had his for the last 15 years and it was still an excellent boat. Short answer is yes - Tim Mumby is the other aluminium mult designer in our part of the world

[David M]

Originally Posted by Dulcesuenos

My own opinions are based on having had an aluminum workboat that was quite expensive when new and also having spoken to people who own a very expensive french yacht made of aluminum. It ends up cracking at weld points. And has horrific corrosion/ electrolysis issues when in salt water. I have seen one aluminum boat fall apart from the inside out as welds seemed to cascade fail from.one end to the next. I will never own another alum boat for use in salt water.

If you have experienced naval architects do the designing and experienced welders do the welding then cracks are minimal to none. Home brew aluminum boats always seem to have more than enough cracks. I would never purchase one of these boats. The professionally made aluminum boats from the big manufacturers like Kvichak are tough as nails. Designing and welding aluminum boats is not a simple thing to do. It takes a good amount of experience to get it right.

As far as electrolysis goes, if you do everything right then their are no problems. But you have to know what doing it right means. I have not had any electrolysis on my aluminum work boat in over 15 years. I learned what my mistake was, made the correction and the electrolysis never came back.

I'm just saying that a near crackless or no crack, no electolysis aluminum boat can be done.

http://www.kvichak.com/

[HapaPops]

I read something on this awhile back - the engineer basically said Aluminum is wonderful, strong and light - but- below a certain size (I seem to remember 50') the weight ends up too high as you need a certain plate thickness in order to get good welds.

You also have to think about a chine boat - which isn't a real issue, but many folks don't like the look. Resale value would also be a concern.

David Vann ignored engineers and NAs - he's lucky he made it as far as santa cruz.