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Old 20-03-2013, 13:06   #16
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Re: Formosa sailing boats

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Originally Posted by boatpoker View Post
The hull is not two halves glued together. The molds of almost every sailboat and certainly all full keel sailboats are made in two halves which are bolted together.

After the hull is laid up (in one piece) the mold is taken apart. This is done because it is simply much easier to get the hull out of the mold this way. It is also done because the top lip opening of the mold is sometimes smaller than other parts of the hull (think tumblehome or reverse transom)
Sorry, guess I misunderstood.

Cheers,
JM.
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Old 20-03-2013, 15:16   #17
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Re: Formosa sailing boats

Maybe a more detailed explanation would help. Obviously I can't speak for all builders but I have seen quite a few.

FRP boats are very difficult to get out of a mold, many are damaged in the process and require some degree of cosmetic touch up. The split mold process I have seen is as follows. The gelcoat is sprayed in first and then a skinout mat is applied. Some people call this a "veil" layer. The skinout mat is a short, random strand glass cloth and its only purpose is to hide the basket weave pattern of the heavier fabrics showing through the gelcoat. It has no structural strength.

The above can be done with both halves of the mold already bolted together or it can be done with both halves separate. Some prefer to do it when the mold is separate because it is a finicky job to get the mat on the gelcoat and separated molds may make this easier. if they do it with separated molds, they may lay in some heavier cloth to stabilize the gelcoat and skinout mat. When the mold halves are put together many more layers of various glass fabrics are laid in with the number, type and placement dependent on the designers specifications.

The effect of this is a one piece structure. When the mold is separated there will be a "cosmetic" flaw i.e the mold "seam". The seam is the line where the mold was joined and most builders fill and fair this after the fact but this seam is often visible in production boats. I believe it is this often visible "seam" (in the cosmetic gelcoat and skinout mat) which causes people to believe that the two halves of the hull were bolted or glued together.
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Old 20-03-2013, 16:33   #18
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Re: Formosa sailing boats

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Originally Posted by boatpoker View Post
Maybe a more detailed explanation would help. Obviously I can't speak for all builders but I have seen quite a few.

FRP boats are very difficult to get out of a mold, many are damaged in the process and require some degree of cosmetic touch up. The split mold process I have seen is as follows. The gelcoat is sprayed in first and then a skinout mat is applied. Some people call this a "veil" layer. The skinout mat is a short, random strand glass cloth and its only purpose is to hide the basket weave pattern of the heavier fabrics showing through the gelcoat. It has no structural strength.

The above can be done with both halves of the mold already bolted together or it can be done with both halves separate. Some prefer to do it when the mold is separate because it is a finicky job to get the mat on the gelcoat and separated molds may make this easier. if they do it with separated molds, they may lay in some heavier cloth to stabilize the gelcoat and skinout mat. When the mold halves are put together many more layers of various glass fabrics are laid in with the number, type and placement dependent on the designers specifications.

The effect of this is a one piece structure. When the mold is separated there will be a "cosmetic" flaw i.e the mold "seam". The seam is the line where the mold was joined and most builders fill and fair this after the fact but this seam is often visible in production boats. I believe it is this often visible "seam" (in the cosmetic gelcoat and skinout mat) which causes people to believe that the two halves of the hull were bolted or glued together.
Thanks Boatpoker, received loud and clear, cheers. Makes sense. Al
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Old 20-03-2013, 16:40   #19
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Re: Formosa sailing boats

I've never seen a hull bolted together.

As far as glued together, I think that is just semantics, I think when people say the half hulls were "glued" together they mean glued with resin and laminates.

You can clearly see in the pictures I posted earlier that the half hull is fully laminated, balsa core has been placed over the outer layers and more layers added on top of that.

Here's a quote from the history of Westsail Corporation:

Westsail Owners Association - Westsail Corporation

Quote:
We would move half the hull mold into the garage (as that is all that would fit), laminate that half, then move it outside. We would then move the other half in, laminate it, then move it outside. We had to do the joining of the two halves of the mold and the centerbond lamination outside, as the garage was not big enough to hold the entire mold. We laminated all four hulls, then all four decks, before starting the completion work on the boats. The newest guy on the crew had the distinct pleasure of doing the centerbond lamination down in the bottom of the aft end of the keel. We usually tied a rope to him to be able to pull him out when he passed out from the fumes. Of course, there were also other plumes of light blue smoke drifting around the yard (remember, this was the early 70s), and the good stuff was coming over from Maui, and readily available without hassle from the cops.
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Old 21-03-2013, 21:32   #20
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Based on what I'm reading here, I may be wrong on my formosa being built in two halves. What lead me to believe it was to pieces was the very distinct seam in the keel when you grind into it when installing new hardware. It extended over the entire area I ground on aft end of keel. The other thing that influenced me is that port and starboard halves are very slightly different in size. Never noticed until painting the boot top, but can see it when measuring, fractions of an inch along hull.
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