Basic fiberglass hull .

What is the easiest method for producing a one off fiberglass hull of about 20' .

 

http://www.cyberstreet.com/andre/

 

Single skin over a mold of some sort, will be the easiest. You can use foam, though there are much less costly options then the foam core products Steve has linked, plus you don't have to sheath the core twice with a single skin layup, like you do with a core.

 

Nice product, what is the preferred resin to use with it?

 

I have thought that covering a male mold with poly , and stapling a a layer of glass on and wetting out might work. Once cured to a green stage ,additional layer would be added . The worst part of this hole deal would be getting the first layer on. I suppose if it were a multi chine design , then I could make fiberglass panels and staple then on to the mold.

 

How about thin glass skin over coosa board? Turn right way up and tape seams and bulk heads joints? She'll be hard chined unless you got fancy with radius curves, etc.

http://www.dixdesign.com/radmetal.htm

The bead and cove book is complete and in-depth, week+ to grok, maybe better to keep a 20fter simple.

Guess it depends on the design?

ps, never did either method, yet. Plan to do the first.

 

Coosa is an interesting product , my guess is that preglassing foam panels is not new and can be done on site. I wonder if there would be any savings.

I wonder if anyone is using cflex , or dura core anymore ?

 

It depends on what you want Frank, but I'll assume, possibly incorrectly that by "easy" you also mean inexpensively. If this is the case, then forget about all the fancy foams, honeycombs and man made materials like Coosa, C-Flex, etc.

If I was to build a one off on the easy and cheap, I'd build a set of station molds out of cheap sheet goods (MDF, particle board, etc.) then spring furring strips over it (ripped from the edges of 2x10's) then cover the whole mold with el cheapo foam, just to have something to fair. Once the foam was faired, I'd cover it with heavy plastic sheeting and layup the single skin. I wouldn't staple it to anything, just use light finishing cloth as the first layer, in manageable sizes, then a traditional laminate schedule of knitted fabrics. Once this was finished, I'd fair the hull, paint then pop the hull shell off the mold. The pieces used in the mold could be used for something else (like a cradle or temporary bulkheads) and now you'd be onto the deck and internal structures.

If it was one of my designs, I'd probably incorporate internal hull stiffeners (like longitudinal girders, sole flanges, etc.) into the hull shell layup, but this requires fore thought and planning, which most backyard builds can only dream about.

 

Now that's the way to do it easy and without spending too much money.
Gets my vote!

 

You can also develop the shapes (sides and bottom ) lay them up on a mica faced table then glass the whole thing together (Chine ,transom and Keel) on a minimally framed jig (So you have room under it) we refer to this as a panel built, it gives a good start on the finishing.

 

Yep, Steve's method is great for a chine hull, though you'll have seams to contend with, you do get to work on smaller, more easily managed pieces during most of the layup. I'm a round bilge guy, so I'd work in or over a mold.