Hull material in Catamarans

[freetime]

Differences in hull material in catamarans.

I am poor in plastic. What kind of plastic hulls does they use.

You say, outremer have solid plast, and i saw schionning have balsa core...

What does these brands have...


Freydis
Outremer
FastCat
Leopard
F-P
Lagoon
Antares
St Francis
Fusion


And what is + and - with these different materials?

[Gludy]

St Francis has solid glass below the water line with a foam glass fibre sandwich above.

Leopard has balsa sandwich throughout - above and below the waterline.

[freetime]

Which is capable damage best, and which weighs less?

Any moisture damage if you use wood IN plast. I know a rib brand and they say NO wood In plastboats.

[sabray]

I would steea clear of balsa, end grain balsa with good saturation of resins may be okay. Balsa does not do as well as clegycell,divinycell (sic)etc when exposed to entrapped moisture. Unless the builder is a high end big dollar I would be concerned the resin ratios are less than adequate for good saturation. It is basic economics.Solid glass or a combination of solid and modern cell marerial is what I would look at.

[freetime]

Does any catamaran use epoxi like Hanse Yachts on their e-models?

[Robertcateran]

My choice is polypropylene honeycomb core but there are so many arguments about the best core I won't say any more about it. You can google on the various cores and get a 1000 different expert opinions.

[Whimsical]

Originally Posted by sabray

I would steea clear of balsa, end grain balsa with good saturation of resins may be okay. Balsa does not do as well as clegycell,divinycell (sic)etc when exposed to entrapped moisture. Unless the builder is a high end big dollar I would be concerned the resin ratios are less than adequate for good saturation. It is basic economics.Solid glass or a combination of solid and modern cell marerial is what I would look at.

I think this may be taking a fairly simplistic view. All cores have their limitations. Some foams don't have very good adhesion to the resin others crumble rapidly if there is a failure in shear. I have read some reports ,from surveyors, where they have found a black ooze coming from foam cores with water entrapment and signs of hydraulic delamination of the skins.
I have seen nothing to suggest that foam is any lighter when comparing panels of equal properties. Point loads can be an appreciable problem with some foams.

I spent a huge amount of time on this and I ended up going balsa but and it is a big BUT.
I tend to think the method of construction is far more important than the core used. I have said it before and have never had anyone challenge it, wish they would as a check on my sanity . I would not use any method of construction where there is any chance of ending up with a network of channels that water can travel around the laminate no matter what the core type. I also would insist on ALL penetrations being finished properly. This applies to all areas of the boat and not just the hull. How many tales of woe are on this forum about soft decks etc.

It is my observation that most people prefer production vessels but for the above reasons I would stay away from most of them and only consider custom made with a set of specs that ensured longivity.

Mike

[44'cruisingcat]

Originally Posted by freetime

Does any catamaran use epoxi like Hanse Yachts on their e-models?

I'd say the majority of Australian built cats are epoxy. Many others like Fastcat and Gunboat also use epoxy.

It's been said before, usually a failure in a balsa core, (or any other core) is due to a failure of workmanship.

Balsa has better sheer and compression strength than any of the foam cores, which allows for either less core material or lighter laminates. For a given stiffness, a balsa cored panel can be built lighter than foam, or for the same weight, a balsa cored panel is stiffer.

[Robertcateran]

Originally Posted by 44'cruisingcat

I'd say the majority of Australian built cats are epoxy. Many others like Fastcat and Gunboat also use epoxy.

It's been said before, usually a failure in a balsa core, (or any other core) is due to a failure of workmanship.

Balsa has better sheer and compression strength than any of the foam cores, which allows for either less core material or lighter laminates. For a given stiffness, a balsa cored panel can be built lighter than foam, or for the same weight, a balsa cored panel is stiffer.

I tend to agree,
the reason for going with polprop honeycomb is price and resilience but have no objection to balsa core or pvc foam,
Robert

[Joli]

That's well said, there is no "best core". I have seen failures with pretty much all the core materials. Buy the boat you like from a good builder and you will most likely have no problems regardless of the coring material.

Originally Posted by Whimsical

I think this may be taking a fairly simplistic view. All cores have their limitations. Some foams don't have very good adhesion to the resin others crumble rapidly if there is a failure in shear. I have read some reports ,from surveyors, where they have found a black ooze coming from foam cores with water entrapment and signs of hydraulic delamination of the skins.
I have seen nothing to suggest that foam is any lighter when comparing panels of equal properties. Point loads can be an appreciable problem with some foams.

I spent a huge amount of time on this and I ended up going balsa but and it is a big BUT.
I tend to think the method of construction is far more important than the core used. I have said it before and have never had anyone challenge it, wish they would as a check on my sanity . I would not use any method of construction where there is any chance of ending up with a network of channels that water can travel around the laminate no matter what the core type. I also would insist on ALL penetrations being finished properly. This applies to all areas of the boat and not just the hull. How many tales of woe are on this forum about soft decks etc.

It is my observation that most people prefer production vessels but for the above reasons I would stay away from most of them and only consider custom made with a set of specs that ensured longivity.

Mike

[mikereed100]

My hull is made from Nidacore with epoxy skins and so far seems to be holding up well. I used Corecell for the main crossbeam and Divinycell for the bridgedeck for their sheer strength but am using Hexacore for the cabin and foredeck due to better insulating properties and cost ($50/sheet for Hexacore compared to $200 for Divinycell)

Mike

[imagine2frolic]

My boat is cold molded with 3 layers of Mahogany. Each 4mm thick in different direction. Several yards have commented how stiff it is when set on blocks. 10 years old now, and holding up well.

[ssullivan]

My hulls are solid glass, which is one of the main reasons I bought the boat.

[sabray]

[quote=Whimsical;192628]I think this may be taking a fairly simplistic view.
I should have thought that out a bit more.
It really depends on what you are trying to achieve. Your point about construction quality and isolating the core so as not to allow channels is also spot on. The material resins and layup schedule and on and on are important in any hull.
I should have said
My preferance would be not to have Balsa. But there are so many factors involved. I think that as weight is reduced and saturation levels are pushed to optimum levels the quality of the builder becomes more important. I probably wont be in the market to have a custom or semi custom hull built. Given that I am weary of Basla I would feal better if the core material were other. So I guess the answer may be everything is okay just make sure its done right and the boat is fitting your needs that may be to simplistic too.

[fastcat435]

Originally Posted by freetime

Differences in hull material in catamarans.

I am poor in plastic. What kind of plastic hulls does they use.

You say, outremer have solid plast, and i saw schionning have balsa core...

What does these brands have...And what is + and - with these different materials?

Freydis = Polyester hand laminated
Outremer = Polyester hand laminated
FastCat = Epoxy infusion
Leopard = Polyester hand laminated
F-P = polyester
Lagoon = polyester
Antares ???
St Francis = Polyester
Fusion = Vinylester
Gunboat = Epoxy prepreg

Polyester is cured with styrene so it has a styrene smell for a couple of years the main advantage it is cheap.
Vinylester is a bit better and definitely stronger since it is a modified polyester .
Epoxy is the ( in my book ) best resin but also the most expensive stronger and a bit more elesaticity.

Greetings