Is that the minimum weight?

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Francis
Posts: 17
Joined: Tue Sep 16, 2014 3:03 pm

Is that the minimum weight?

Post by Francis » Thu Sep 13, 2018 12:26 pm

Today I finished my first stripper, a racing C1 canoe (17 ft long). When I weight the boat, I was a little bit disapointed with the 16 kg (35 lbs). During the whole building process I was trying to keep the weight low. Strips: 4,8 mm, Outside: 4 oz fiberglass and 3 layers epoxy, Inside: 2,8 oz fiberglass and 2 layers epoxy. No stems, and only a small inner gunwale (Obèche). Thwarts are in Aluminium. Seat and pedestral in carbon. First I want to do a test paddle before I'm gonna apply the Epifanes. I was wondering if that's the minimum weight I can have for a 17 ft canoe? Because the building was so much fun I have the intention to build an USCA C1 stripper, but I want build them as light as possible, because next year I participate in a canoe race with 78 portages.... I don't gonna paddle the boat in shallow waters, mostly canals.
I was thinking if it's a good idea to fiberglass the outside again with 4 oz fibeglass, 1 layer epoxy and 3 layers Epifanes. Inside: no fiberglass only 1 layer epoxy and make a few 'ribs' with carbon weave to give strength + also 3 layers Epifanes.
Any advice is welcome

sedges
Posts: 290
Joined: Fri Jul 09, 2004 5:37 pm
Location: georgia

Re: Is that the minimum weight?

Post by sedges » Thu Sep 13, 2018 1:51 pm

No glass on the inside is a bad idea. Any impact from the outside is absorbed by the inside glass. I would consider using lighter glass on both inside and out. A lot of weight is resin to fill the weave of the glass. Look at the thickness of various glass fabrics. Your 4 ounce glass is real thick, it takes a lot of resin to fill the weave. There is a 2.5 ounce cloth that has 64x60 threads per inch at .0032 in thickness. Compare to the 4 ounce at 24x22 threads per inch and .0048 in thickness. The 2.5 is likely stronger with the higher thread count and uses about 30% less resin to fill. You could use that on the outside and inside with an extra layer in the flattest section of the bottom (inside)for stiffness. Forgo all the layers of resin over the cloth, use only enough to fill the weave and have a smooth surface on the outside, no need to have a glossy surface on the inside just wet out the resin. Squeegee out the excess resin well. This is hard to do on the inside, but be persistent. I think you might shave off a few pounds if you experiment with lay up and resin management. Consider high end products like carbon fabric as well if you have deep pockets full of cash.

You are about 10 pounds above a fabric and foam core carbon fiber stock boat. I believe that cutting that difference in half is going to be about the best you can do unless you vacuum bag your glassing process and use carbon fiber/kevlar.

Francis
Posts: 17
Joined: Tue Sep 16, 2014 3:03 pm

Re: Is that the minimum weight?

Post by Francis » Thu Sep 13, 2018 3:56 pm

Thanks a lot for your feedback! My 'first' experience with the 2.8 oz fiberglass was a difficult one. Because the fabric was not wide enough, I couldn't use it in the length but I worked in strokes from gunwale to gunwale with an overlap of 4 inch. The problem was when I put the epoxy on it, at the overlapping stroke, it was very difficult to remove the epoxy in the overlapping stroke with the squeegee with the result that I have some small wrinkles and maybe to much epoxy. Is it better, when you have overlaps, first wet out the resin on 1 stroke, let it dry a little bit, sanding the edges and then add the second fiberglass stroke? It was also difficult to hold the light fiberglass on place. If you say for the inside 2 layers, the same questions as above: wet out 2 layers in one time or 1 by 1?
About the carbon fabric instead of fiberglass: is it correct that you need more epoxy to wet out = more weight?
I want to build as light as possible, but not 'stupid" light :-)

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Jim Dodd
Posts: 1161
Joined: Wed Feb 08, 2006 11:08 pm
Location: Iowa

Re: Is that the minimum weight?

Post by Jim Dodd » Thu Sep 13, 2018 8:06 pm

Vacuum bagging, and investigate Innegra .
Skip the varnish !

Jim
Keep your paddle wet and your seat dry!

sedges
Posts: 290
Joined: Fri Jul 09, 2004 5:37 pm
Location: georgia

Re: Is that the minimum weight?

Post by sedges » Fri Sep 14, 2018 3:10 pm

If your cloth puckers along the edges it is sometimes helpful to cut off the selvedge, the finished edge of the cloth. That releases the fibers to adjust to a contour a little better. I like to leave the selvedge on if I can, because its neat, but I don't hesitate to remove it if it will let the cloth lay flat.

Some high thread count plain weave cloth does not conform to curves well. It is helpful to get samples or small quantities to experiment with if you are getting away from the standard 4 and 6 ounce boat cloth. There are a lot of fabric styles out there, some can be the devil to work with if used for the wrong purpose.

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