Hull layup

[Irwin32]

I am looking at a boat later this week which is owner built. I am aware of the risks. What I need to know is what C flex is. Here is the description I was given. It was built with a wood plug, inverted and applied C-flex and subsequent layers of 24 ounce woven/roving and 1 1/2 ounce mat. Hull thickness at keel is 1" at the turn of bilge 5/8" and at the shear 3/8". After removing from the plug, layers of woven/roven and mat were applied inside the hull.

I understand woven/roven and mat. Is the wooden plug an inside mold over which the hull was built? does "inverting" mean that the hull was built from the inside out? Please don''t answer unless you know for sure.

It sounds to me like this hull is very solid.

[Jeff_H]

C Flex was one off boat building system which used a female mold and a product that consisted of fiberglass rods and cloth for the first layup. The female mold was generally more of a series of frames and closely spaced ribands similar to wooden boat construction. The rods in the C Flex allowed a certain amount of bridging of the frames and so was supposed to be to some degree self-fairing. C-Flex boats were generally constucted upside down and from the inside, out toward the exterior skin.

C-Flex produced a fairly heavy but not especially sturdy boat because it took a lot of material to get one faired up. I helped fair one in Savannah and is was enormous work to get fair. We ended up grinding down through quite a few glass layers in places and filling other deep dips in others. It was a real pain to get to look even halfway decent.

C-flex was replaced as a popular amateur one off boat building method by a variety of techniques such as cold-molding and various cored techniques that produced lighter, fairer, and stronger boats, often with a lot less effort.

In any event, I would expect a very heavy, but not especially sturdy or fair hull. Also this was a technique that was NOT very popular with the more reputable high quality designers so I would also be suspect of the design.

Jeff

[Irwin32]

Interesting comments. I have since looked at this boat and found the bottom of the hull (as opposed to the topsides) to have areas of roughness. Also, the hull showed some blistering problems. Some had been repaired, some had been opened up to dry, and others were waiting for work. Thanks for your comments.