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Old 24-02-2014, 16:34   #16
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

I don't see why that is mind blowing - a boat that is 11 feet longer and 15 feet wider weighs the same as yours. In build size, it is double the size of your boat (I'm adding in freeboard and cabin to the catamaran here), so unless the weight of your lead is equal to the entire displacement, this makes sense to me. And yes, they are probably loaded with more gear than you.

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Old 24-02-2014, 18:20   #17
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Colemj,
I always thought cats to be light and fast.
no lead.
There's no hull underwater.
So I assumed they'd weigh nothing.

I bet there's more hair curling irons on cats.
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Old 24-02-2014, 18:21   #18
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Parmenter -

I'm not here to argue what's better, and why. That's not what this thread is about. My point was that either system is good, if used in accordance to each resin's strengths, and avoiding their weaknesses.

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Old 24-02-2014, 21:24   #19
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Quote:
Originally Posted by endoftheroad View Post
Colemj,
I always thought cats to be light and fast.
no lead.
There's no hull underwater.
So I assumed they'd weigh nothing.

I bet there's more hair curling irons on cats.
Well in general, a 45x23' platform requires a certain minimum of resin, glass, core and associated metal parts just to simply cover that area and keep from falling apart. They really are twice the size of your boat.

Even daggerboard cats draw 2.5-3.5', so there is some hull underwater. Not to mention that to get this all to work they will have twice the freeboard and double the cabin top area. A 10T 45' catamaran is neither heavy nor light. They are not made of helium, and must follow physical and engineering laws.

But if you are looking for a "wowzer" moment, consider that the new Lagoon 45 tips in at a whopping 38,000lbs with no options, no fuel, no water, and no provisionings! And that is Lagoon's published figure - they have been very bad with the truth in this figure over the years.

Yes, some catamarans are very heavy.

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Old 24-02-2014, 21:54   #20
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

And at the other end of the spectrum a Schionning GForce of that length runs around 6.5T so some boats are very light.;
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Old 25-02-2014, 02:00   #21
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

I was disappointed the boat I purchased is made from VE rather than epoxy. Makes me feel better knowing the "best" prod boats still use poly!

Here is a blurb from Catana mentioning the use of VE.

Quote:
The Twaron Impact process uses vinylester resins that have the same mechanical properties as epoxy resin, without the inconvenience in use or of subsequent repairs.
I read that as possibly only the Twaron (kevlar?) area is infused with VE. The rest could well be poly. Apparently poly is a huge no no with Kevlar type fibers as it just does not bond satisfactorily to it.

Twaron impact - Technology - Catana - Catamarans - Cruising
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Old 25-02-2014, 02:04   #22
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Sounds like Catana probably use a bare minimum of VE. Probably as a barrier coat, and in the areas were Twaron (kevlar?) rules out poly as it just wont stick to it.

Infusion - Speed - Catana - Catamarans - Cruising

Quote:
A brief technical explanation: fibreglass, carbon fibre and aramid (Twaron) are the basic construction materials used, but these are soft materials like basic fibres. An aggregate needs to be created to achieve the rigidity required for facing the elements. We therefore apply a resin, made of vinylester and polyester.
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Old 25-02-2014, 02:09   #23
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Outremer 49. I too am shocked and amazed that these higher end prod boats use the cheapest resin. At the cost of these boats, what would the % price difference be if they use VE? Probably a couple of %?

Outremer 49 | Sail Magazine

Quote:
The primary resin used is polyester, with vinylester in the skin coats and an NPG gelcoat for enhanced blister resistance.
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Old 25-02-2014, 03:14   #24
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

We did panel testing several years ago when choosing the resin for a 14m cat. It was fun making up the panels so we went a bit crazy doing all sorts of combinations of cores and glass and resin. Then did the drop test ( for impact resistance) with the 10 kg ball from various heights to see what happened.

I learned the superiority of good epoxy for impact resistance. (1) Poly was hopeless and fractured extensively with major crack propogation, (2) vinylester was marginally better, the crack propogation was not as much, (3) we tried West Systems and System 3 epoxies. West system wet out easier, was very clear (not important at all) was very good on drop test, but not nearly as tough as the System 3 resin which was remarkable. We used the System 3 which was only a bit more expensive. Not significant cost increase, and totally insignificant compared to value of the boat and the difference it can make to preventing delamination, osmosis and impact damage both as a direct hit (say hitting a log) or repeated cycles of impact from wave impacts.

Why scrimp on materials costs?
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Old 25-02-2014, 04:27   #25
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Quote:
Why scrimp on materials costs?
Let me say right up front that I know nothing about Poly, Vinylester or Epoxy. I am simply an uneducated consumer trying to work out this stuff.

What I do know based on quotes for boats both o/s and in Australia is that there is a significant difference in price between these materials in a boat of the same size, and here I am talking about in some cases EXACTLY the same boat.

As I understand it, it is not only the cost of materials but also the cost of working the materials.

Based on the info I have the relevant costs are :-

Base price poly with vinylester coating
Add epoxy underwater - +5%
Vinylester construction - +15%
Epoxy construction - +30%
Carbon Fibre - 100+%

So what is the value equation here. As far as I am told Outremer for instance has had no cases of delamination or osmosis in any boat. In fact if you strip out the well documented cases of osmosis for production boats prior to the use of vinylester coatings there are vitually no cases of osmosis to report for production boats since using vinylester coatings.

As far as repeated cycles from wave impacts, I know poly boats that are over 15 years old and have gone around the world and are still in good shape.

I understand that these materials create stiffer structures but what exactly are the implications of this. How do I weigh up the extra cost? Certainly weight is not an issue (leaving aside carbon fibre) as weights are quoted as similar.

It seems to me that the issue is not one of materials but rather workmanship, and a good poly boat properly laid up with properly applied vinylester coatings will perform quite adequately.

Can anyone really give me a good reason to spend these extra $. Please do not tell me I can build my own for little difference. I would not breath that stuff for all of the money in the world.
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Old 25-02-2014, 09:47   #26
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Epoxy would make the boat lighter, and thus go faster and/or use less fuel.
The issue is mostly that adding the washer and dryer, extra bedroom and bath (oops quarters and head 300lb dinghy, extra 50 gallons of water or fuel, two diesels vs one, etc, just undid any weight savings.
So for a loaded cruising boat, the weight savings isn't all that significant.
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Old 25-02-2014, 13:15   #27
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Quote:
Originally Posted by endoftheroad View Post
You know, that blows my mind that a cat weighs that much.
I'm the "lead hauler" and I'm 10 tons.
It must be the big screen tvs and dishwashers you guys have
In them boats.
Yesterday a motorboater here in the anchorage told me he was 33,000lbs,
I flipped out!
It amazed me too, when I found the weight of these boats. Supposedly resin infused, foam cores - all the good stuff for a light boat, but then the weight...

But not all cats are that heavy. Ours weighed 4.8 tonnes at launch. And it wasn't empty.
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Old 25-02-2014, 13:20   #28
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Quote:
Originally Posted by cwjohm View Post
Let me say right up front that I know nothing about Poly, Vinylester or Epoxy. I am simply an uneducated consumer trying to work out this stuff.

What I do know based on quotes for boats both o/s and in Australia is that there is a significant difference in price between these materials in a boat of the same size, and here I am talking about in some cases EXACTLY the same boat.

As I understand it, it is not only the cost of materials but also the cost of working the materials.

Based on the info I have the relevant costs are :-

Base price poly with vinylester coating
Add epoxy underwater - +5%
Vinylester construction - +15%
Epoxy construction - +30%
Carbon Fibre - 100+%

So what is the value equation here. As far as I am told Outremer for instance has had no cases of delamination or osmosis in any boat. In fact if you strip out the well documented cases of osmosis for production boats prior to the use of vinylester coatings there are vitually no cases of osmosis to report for production boats since using vinylester coatings.

As far as repeated cycles from wave impacts, I know poly boats that are over 15 years old and have gone around the world and are still in good shape.

I understand that these materials create stiffer structures but what exactly are the implications of this. How do I weigh up the extra cost? Certainly weight is not an issue (leaving aside carbon fibre) as weights are quoted as similar.

It seems to me that the issue is not one of materials but rather workmanship, and a good poly boat properly laid up with properly applied vinylester coatings will perform quite adequately.

Can anyone really give me a good reason to spend these extra $. Please do not tell me I can build my own for little difference. I would not breath that stuff for all of the money in the world.

I can't see these figures being correct. For a start, the hull/deck structure is only about a third (or less) of the overall cost. And the resin is only a fraction of the hull/deck cost.

Epoxy is expensive, but I always thought vinylester was fairly close to polyester in price.
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Old 25-02-2014, 15:00   #29
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

1. Catanas are known for really good bridgedck clearance. When you raise the structure out of the water it makes the freeboard about a foot or so taller and that adds significant weight. Catanas do sail very well so they have something figured out. If you want a lighter boat with less freeboard then something like a Voyage 450 might do. It does have a fairly low bridgedeck clearance.
2. I expect a significant part of the weight is the interior furnishing. Lagoon ain't using honeycomb core veneers if you know what I mean.
3. I haven't been on a L450 but I have been on a L440 and that is a massive boat. Some of you mono people should just visit one and you will immediately understand why it is so heavy. It is 3 levels: the hulls, the salon (bridgedeck) and the fly bridge. Very impressive.
4. Poly is so easy a chimp can do it. The mix ratio doesn't have to be precise at all and their is a wide range were the resin is doable.
5. Epoxy is not tolerant of sloppy mixing at all. A minor variance and the goo ain't gonna go and you are screwed.
6. To build a strong enough poly boat you just keep layering resin and glass To build a strong light epoxy boat you have to get the mix right and use the minimum of glass to achieve the strength needed. There is little room for error. Many epoxies benefit from heat curing also and that's a big oven to slide that cat into.
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Old 25-02-2014, 16:02   #30
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Re: Epoxy vs. Vinylester vs. Polyester in production Catamarans

Quote:
Originally Posted by nimblemotors View Post
Epoxy would make the boat lighter, and thus go faster and/or use less fuel.
The issue is mostly that adding the washer and dryer, extra bedroom and bath (oops quarters and head 300lb dinghy, extra 50 gallons of water or fuel, two diesels vs one, etc, just undid any weight savings.
So for a loaded cruising boat, the weight savings isn't all that significant.
Failed logic and maths.

If I have a 5000kg epoxy boat and add the same items mentioned above it will be how much lighter than the 6500kg polyester boat with the same items onboard?
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