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Old 11-05-2013, 01:02 PM   #21
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Good boats can be built of wood, fiberglass, steel, aluminum, carbon fibre, and cement, bad ones as well.

Advantages of one material over another depend on intended use, budget, availability of the material and labour skilled in its use, and longevity or cost/benefit.

High-speed boats require light and stiff materials to be possible, heavy displacement boats can be built from anything but super-light construction may be detrimental.

One measure of a materials usefulness might be stiffness/weight ratio. Steel is quite stiff (it resists bending) but very heavy. Carbon is even stiffer, but very light. There is a huge difference in cost between the two. Fiberglass is not very stiff, but it's cheap so you can use a bunch, which makes it heavy, but that's okay because HP is cheap....er....well not so much any more......thus the proliferation of cored fiberglass today.

Another measure of materials is fatigue. We've all bent a piece of copper wire three times and it breaks (reached it's fatigue limit). But bend a similar piece of wood and nothing much happens? Keep on bending it.....hummm.....nothing....when will it break? Well it might not....high fatigue limit. It turns out fiberglass fatigues fairly quickly, as does aluminum (especially in the welded state), steel more slowly, and wood has the best resistance to fatigue. But wood has other drawbacks, low resistance to moisture, lack of availability, etc.

Each material and construction method has both advantages and disadvantages. And each application can use those advantages or not.....

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Old 11-05-2013, 03:59 PM   #22
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Is cleaning, painting, repairing and upkeeping FG is harder than Wood? I never work on a boat but have some experience with wood.

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Old 11-05-2013, 06:38 PM   #23
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Originally Posted by Josan89 View Post
Is cleaning, painting, repairing and upkeeping FG is harder than Wood? I never work on a boat but have some experience with wood.
I would say much easier. I just regularly clean and polish/wax the fiberglass. The gelcoat (hard, outer protective skin if you will) can get faded and chalky over time but can usually be cleaned up with some elbow grease. I regularly inspect for cracks and "crazing", which can lead to delamination of the fiberglass. Balsa core rot is something to watch as well, but many boats are foam cored (foam doesn't rot like balsa but will deteriorate).

Gelcoat that is cosmetically fargone may require painting with such products as Awlgrip or another comparable, marine coating.

I'm not a fiberglass expert, but I learned a lot from hours of reading on the net about preventative maintenance and repair of fiberglass--wealth of resources out there!
“Go small, go simple, go now”
― Larry Pardey, Cruising in Seraffyn
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Old 11-05-2013, 09:28 PM   #24
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Fiberglass construction is plastic, glass fibers laminated together with wood or other materials to give the weak FG membrane enough stiffness to be strong enough to hold together.

The end product is just barely strong enough and at least half again as heavy as it would be if it were plywood or similar light wood construction. Not saying plywood is perfect of course but it is strong and light. It's also easy to repair and quick to build.

The ideal material is probably a "cold molded" boat or one made from small strip planks held in place by a glass/epoxy overlay on both sides. Like some canoes.

I once heard a man bragging about how much better his Reniell boat was compared to his friends Bayliner. They both had their boats shipped up on a barge and were the same size but the Reniell was heavier. The man probably bought anything that said "heavy duty" ... cause the word heavy was there. My dad liked everything "skookum" also. But lightness is a boaters friend and is the road to performance.

But don't ask me if my boat is light.

FF, The problem w ferro cement is that it is reinforced w steel and of course it rusts.

North Western Washington State USA
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Old 11-06-2013, 01:40 AM   #25
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Originally Posted by FF View Post
I've seen more ferrocement hulls on land and unfinished than completed projects in the water.

That is because on a sail boat the hull at best is 15% the cost of the boat.

Most of these folks could not afford to finish a FREE hull.
Oh, so true. I have a cousin who started a ferro cement yacht, 55' of it, back in 1978/ He did a beautiful job of the hull, but it is still up in a cradle somewhere waiting to be finished. It was the fit out that cost the small fortune. He says he still hopes to finish it one day...

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