Hull Fairness

[Guest Lance Turner]

This is a general question regarding hull fairness. Develin's book regarding epoxy and cloth shows an example of applying epoxy and cloth to the outside bottom and sides using four separate pieces of cloth. The hull example in the book is very close to the Bay River Skiff. The pieces of glass cloth overlap at the keel and chine to give extra strength to those areas. For discussion purpose, lets say the glass cloth is 6oz. Another method I have read about is to tape the chine with 3" wide glass tape then cover all with the glass cloth. My question is, which method will produce a fairer hull without doing a lot of fairing using epoxy mixed with a low density filler. I guess I'm concerned about the areas where the glass cloth overlaps. I would like to know what B&B recommends regarding epoxy and glass sheathing of a hull. Thanks.

wturner497@aol.com

[Guest Tom Lathrop]

Lance,

The real question is whether the cloth can be made to fit over both bottom and side in one piece. Only on small boats where the keel to sheer distance is less than the width of the cloth is it possble to try laying the cloth in one piece. Sometimes there is too much compound shape for the cloth to be fitted without cutting it at the chine.

It's a matter of either choice or necessity really. Works either way, but fairing the chine may be easier when the tape is put on, edges faired and then laying the cloth in a single piece on both bottom and side. Sometimes, if the cloth is too narrow to cover both bottom and side all the way to the keel in the middle sections, I place another piece of cloth over the void in this area.

harbinger@cconnect.net

[Guest Joe Nelson Oregon CS20 #3]

Vee hull are easier to use the method described than are flat bottom boats...because the angle between the sides and bottom is greater on a flat bottom boat. This increases the likelyhood that you will get wrinkles in the glass as you wrap it over the chines.

If you seam the glass and overlap at the keel, it would take a really big boat to make 60" wide cloth too narrow.

I am an advocate of sheathing the hull with glass. Because of the coats of epoxy necessary to fill the weave (3 or so) it assures a great epoxy barrier over your hull... aside from the other physical properties. But as to your question of fairness. Glass tape is cheap. I would run the tape on the chines...let it dry and sand the edges to a taper...then sheath the sides and bottom separately without the overlap that Devlin illistrates. Do the sides first and then the bottom... glass over the chines about a half inch. When dry sand smooth at the chine without cutting into the tape under the cloth. Now do any fairing necessary with microballoons and epoxy. Followed by a couple more coats of regular epoxy.

I dont think you can totally avoid the fairing process. The key is to do it only once. In the past I have done it 2-3 times between various processes. (wastes time and materials) Get on all your glass and fair one time. Then do your epoxy coating.

joe_nelson22@hotmail.com

[Guest Graham Byrnes]

I don't think that it is absolutely necessary to sheath a skiff. My own BRS 15 was not glassed and was 12 years old when I sold it and the hull still looked good. I did repair the occasional ding over the years and maybe at least one of those would have penetrated the glass. I had a metal keel strip and about a 4' metal strip under each chine so that I could let her run up a concrete ramp and flop over on to a chine without damage.

When I glass a hull like a skiff I like to have all the taping, if any, and all fairing done before I glass. You can go from the sheer to the keel in one piece on a skiff type hull if the glass is wide enough because the glass is loose weave you can cover compound surfaces. I avoid having any joins on the sides prefering to fair the bottom if the glass is not wide enough and start with my cloth following the sheer carrying it up over the chines to the bottom. I drape the glass in position over the hull and start amidships using a dust brush smoothing out the wrinkles and milking out excess cloth toward the ends. If you start with a smooth fair surface and you squeegee out the excess resin just right and fill the weave carefully you should have very little fairing to do.

[Guest Greg Luckett]

Graham,

Do you have any pictures or information which you would/could share about those metal strips? Sounds like a good idea, but I am not clear about how to do it.

Thanks.

luckettg@qtm.net

[Guest Graham Byrnes]

Greg,

The metal strip can be brass 1/2 oval or SS hollowback about 3/4" wide, bolted through the chine as far outboard as possible. The easiest way to find the fore and aft position is to lay the boat over on the chine and the point where the chine touches the floor will be the center of the strip.

The only boat that I have right now with a strip on the chine is a Catspaw. I can take a picture of it and email it to you if you like.

[Guest Greg Luckett]

Graham,

I just found your reply while playing with my forum settings.

Yes, if it is not too much trouble, I would really appreciate a picture via email

Thanks again,

Greg.

luckettg@qtm.net