Would love to hear the cons and pros of ALUMINIUM vs FIBERGLASS catamaran Sailboat

[amalam85]

Hello everyone,

My partner and I are looking into buying a catamaran sailboat. And our first thought is what would be safer, stronger, more affordable, better cruising etc. We are new to the subject so would love to hear feedbacks. We are planning on cruising around the world so we want something that would fit our itinerary and have decided on multihull since we love the extra space and accessibility to our favorites bays.

Thanks veru much for your help!

[44'cruisingcat]

I've never owned an aluminium boat. But when I was investigating building my own I did look into aluminium a bit.


Some of the pro's and con's I found were:


An aluminium boat will generally be heavier than a cored fibreglass boat.


It's difficult to get paint to stick to aluminium long term.


You have to use antifouls that suit aluminium. These are not as effective.


Metal boats can tend to be hotter, colder and noisier. You can add insulation, but this also adds weight.


IMO fibreglass is better suited to DIY repairs. It's quite easy to carry around some epoxy, glass and filler. A MIG or TIG welder, not so much.


Aluminium is stronger though, so you're less likely to need to repair it.

[snort]

I think an aluminum catamaran would be a very rare find. I have a hard enough time finding a suitable fiberglass one at my miniscule price point, which isn't minuscule by monohull standards.

[44'cruisingcat]

There are quite a few in Australia, but you're right, AFAIK there aren't any production built ally cat's.

[SaltyB]

Originally Posted by 44'cruisingcat

Some of the pro's and con's I found were:


An aluminium boat will generally be heavier than a cored fibreglass boat.

I'm pretty sure aluminum will be both lighter and stronger than fiberglass but at a higher cost. My experience is with aluminum power boats though so it may not apply to sail boats.

[Factor]

There is a practical crossover point for Aluminium and FRP. Under about 13 Metre FRP will be lighter, all other things being equal than Aluminium. Over 14 metre Ali can be lighter that FRP. This is based on designs that aren't seriously fat to begin with.

44C has highlighted some of the challenges of Ali. They are all valid. I would add one old saying that a surveyor mate of mine used to tell me about Ali boats - "trouble with aluminium is that once you build a boat you have to build another boat inside it" meaning that to get quietness and decent insulation there was a lot of work inside.

Having said all that I really like Aluminium in a good design around the 14M to 15M size.

Tim Mumby - Mumby Owen Easton Eastonand Peter Kerr Lizard Yachtsare three good designers in Australia who have made some very nice boats.

I owned a Peter Kerr boat (in strip cedar not ali) and he is a very nice chap to deal with.

A a good ali boat is a good thing, so long as you recognise its challenges. You can pick up a good Australian ali boat for round $400-450K australian, and given our dollar isnt worth much, it would be a reasonable option to buy one in Australia and then going tripping around.

[44'cruisingcat]

Originally Posted by SaltyB

I'm pretty sure aluminum will be both lighter and stronger than fiberglass but at a higher cost. My experience is with aluminum power boats though so it may not apply to sail boats.

If you were comparing solid fibreglass power boats to ally powerboats, then yes. But we're not really talking about these.

A CORED glass non trailerable sailing boat will be lighter. Usually.

As Factor said, with ally you have to build an interior inside the shell. With cored fibreglass you can usually fair and paint the insides of the shell to get your interior.

I'm not talking about production boats, because AFAIK there are no production aluminium sailing cats available, so no point comparing apples to oranges.

[noelex 77]

As aluminium boats are not produced in a mould and the internal fit out is normally non structural, it is therefore much easier for the manufacturer to incorporate changes. So aluminium boats typically have a greater range of customisable options.

It could therefore be argued that all aluminium boats are "semi-production" rather than true "production" models, but Garcia and Alumarine produce a range of cats that are as "production" as you are ever likely to see in this material.

Kat'alu 43

Full test by Multihulls World - GARCIA YACHTING - Garcia Banana 43 - multihulls-world.com

Note Grand Large have taken over Garcia and Allumarine so I expect these two ranges will be consolidated. With input from Allures I would expect more models to be released especially larger designs where the greater hull cost of aluminium makes more sense.

[Sand crab]

Actually Prometa has been producing aluminum cats for decades. They made Banana Split in 1989 which is owned by "Antoine". He has made a career of travelling, singing, and filming his cruising adventures. If you are french then you are probably familiar with him. Prometa was bought by the Garcia group I believe and that Banana 43 is the evolution of Antoines boat.
http://www.antoine.tv/index-en.php?a...e&idp=5&srid=7

Yapluka made large production aluminum cats but went belly up a few years ago. Those boats still sell for a hefty price. I wonder if the remnants are part of the Garcia family now?

[Factor]

I dont think Yapluka ended up in Garcia. Garcia BTW is part of the group that produces Outremer, so the family does know how to build a strong fast Cat.

[catman]

A consideration in regards to aluminum is the potential problem of electrolysis the electrolysis can originate from inside or outside the hulls.
If a dissimilar metal should happen to touch the inside of the hull for an extended period of time, say a copper penny, that could lead to a hole in the hull. I removed the aluminum fuel tank from my Fontaine Pajot catamaran and found that coins had found their way between the deck and fuel tank.
The bottom of the tank was severely pitted and had to be replaced.
Mooring in a marina with heavy use age of shore power by other boats could also affect your aluminum hulls.
The design and install of an anti-electrolysis system would be a worthwhile investment.
Good luck on your decision.
Catman

[ex-12m-guy]

Hit a reef in a fiberglass boat, and you get a hole.

Hit a reef in an aluminum boat, and you get a dent.

We owned several aluminum boats over the years.
They are strong and tough. However, careful attention
must be paid to potential electrolysis problems.

Zinc sacrificial anodes are OK in salt water. Change to magnesium
(or no anodes) if in fresh water for an extended period.

An isolation transformer is a MUST for any aluminum boat connected
to AC shore power.

Be very careful about DC wiring. Do not use the hull structure as a negative
return for electrical devices, no matter how handy it may seem.

[Russ]

Read the posts and you're getting lot of mis-information.

FG is fine BUT aluminum much better. Never has blisters and ALL FG boats do eventually, that's why no one offers a lifetime blister guarantee. Al fittings never leak or come loose like FG chain plates, assuming they are all welded to the hull as they should be.
Al is as light as anything else, the insulation which must be done below the water line is light. You NEVER paint Al unless you like to paint. You let it age and get the Al patina. Only the bottom gets bottom paint which sticks just fine IF you prep the hull as it should be, the deck is best covered with non skid like Tredmaster.

I own steel and the ONLY draw back to AL is electrolysis which is why Al must have an isolation transformer ( Not a galvanic isolater).

Why does Jimmy Cornell sail a mono from Alubat OVNI (France). By the by most boats in Europe are METAL!!!!!!!!!!!!!!!


Metal Forever! Russ

[DerekKelsall]

During the last five years we have designed a couple of 51ft. sailing cats and a 43ft. power cat which were built in aluminium in Korea. Similar designs have been designed in foam fiberglass sandwich to similar standards. The foam sandwich boats are approx. 25% lighter and this is before adding insulation. The build time compared to KSS (for the structure) is at least double. In 50 years of designing and building in foam, I have never seen or heard of a hole right thro. with the exception of one 42 ft., fast ferry in Vietnam which ended on rocks. The rare Outside skin damage is easily repaired.

Our spec is for high quality paint treatment - no osmosis. Just received a report on a 32 ft. tri launched 39 years ago. No structural problems. Many more years of service anticipated. I have several such reports. The boats I was involved with going back to 1965 keep coming back to me. For example, three sister ships of my first design Toria are still sailing. Another client who has sailed his own built 39 ft. since 1976 reports having painted only once completely and has replaced his rigging once only.

I have also designed for steel. Metal well maintained is durable, but the claims to be superior to sandwich composites are not substantiated in my experience.

Happy boating,

Derek.

[Jim Cate]

By the by most boats in Europe are METAL!!!!!!!!!!!!!!!

This revelation will, no doubt, be a surprise to Beneteau, Jeneau (sp?) et al...

Jim