CS17 -- taping seams

[Charles Neuman]

The plans call for 10 oz tape on the seams. I am reading Sam Devlin's book now. He recommends cutting your own 4" tape from a larger piece of cloth so that you have loose edges. Otherwise, the woven edges of the tape may not lay flat, and they could trap air bubbles. Do most CS builders follow Devlin on this one? Or does the tape work fine?

Also, is there any need for biaxial cloth on the seams? Devlin recommends this, too, for added strength. Most of Devlin's boats are bigger than the CS17, so maybe it's not much of an issue here.

While we're at it, do most people glass the hull? I enjoyed the thread on that topic. Anyone want to comment on why they did or did not do it to their boat?

Thanks,

Charles

soon-to-be CS17 #135

[Brent]

I am just putting the final coats of epoxy on a Spindrift with taped seams. Used tape with no problems, it went just as Ray suggested; some scraping, and filled with microballs. End result is very fair, and the taped seams will not be visible.

I built a CS20 with a glassed hull, and am glad I did. I skipped taping the seams entirely and laid 6 oz glass over the entire hull. I wanted the extra protection for the wood underneath. The glassing was easy to do and aded maybe 10 lbs to the hull. End result is strong, fast and built to last. Bottom line is personal preference.

[Designer]

You will be fine if you follow the plans. Sometimes the selvage edge can stand up because it may have been woven tighter than the cloth. If that is a problem with your tape you can cut the edge of the tape every foot or so to relieve the tight edge. Bias glass 45/45 is slightly stronger than 0/90 tape because all of the fibers run across the seam. We use bias glass in our larger designs but it is overkill on the CS17. It is more important to do a good job on your seams than to change the glass.

I have discussed glass weight over seams with Sam and he says that he deliberately over-designs his seams. The Gougeon brothers use lighter glass on their seams and claim that it is better. I prefer to be in between with a little more glass than necessary which gives a margin for sloppy work but without excessive weight or cost.

It seems that most people glass the outside of there CS17's. Mine is glassed and I am happy that it is. It gives me a bit more ding resistance.

[Charles Neuman]

Thanks for your comments. That's interesting that Sam Devlin overdesigns his seams. Many of his boats are pretty large, which might be related to that. Even the small boats seem like large boats. The 15' Nancy's China weighs 800 lbs! Almost 300 of that is in ballast. It must drive like a truck, but I'd feel pretty safe in it.

It seems people have various reasons for glassing the hull. It's helpful to hear them. Thanks, everyone!

Charles

[Charles Neuman]

One more question: I found one place that sells 8.5 oz tape, but not 10 oz. Is there much of a difference, or should I keep looking?

[Designer]

8.5 oz will reduce your safety margin but I recall that you are going to glass the outside of your boat which will bring up the safety margin back up.