graphite, and chines

Sandy, My
other and I are building a balsa boat, we started last spring, and are now nearly ready to pull it of the strongback. We have not put the final finish coats on so I have a few questions. What is the purpose of the graphite powder on the bottom. How sharp should the chines be, and how crucial is it that the chines be true. Are a few wiggles and waves ok, or do we need to fill in with resin, etc. I understand that the chines will be the determining factor in how the boat tracks. Thanks for your times and plans. Others who have looked at our boot are very impressed. tom

In reply to "graphite, and chines", posted by Tom Trow
idge on Jan 26, 2001:
>Sandy, My
other and I are building a balsa boat, we started last spring, and are now nearly ready to pull it of the strongback. We have not put the final finish coats on so I have a few questions. What is the purpose of the graphite powder on the bottom. How sharp should the chines be, and how crucial is it that the chines be true. Are a few wiggles and waves ok, or do we need to fill in with resin, etc. I understand that the chines will be the determining factor in how the boat tracks. Thanks for your times and plans. Others who have looked at our boot are very impressed. tom



I need to say more about chines in the instructions.
The rounder the chines are, the more durable they are.
The sharper the chines are, the better the boat tracks.

I usually make the chines as sharp as I can, and then round them off slightly, and then
glass the sh*&t out of the chine. Extra glass on the chine is more important on
balsa boats than it is on plywood boats. I have an old balsa boat with a very rounded chine.
It is now 15 years old, including 5 years full-time guiding on the Yellowstone. I have had
to gouge wet balsa out of the chine 2-3 times in 15 years, refill with putty and then
re-cover with tape.

Last year I did that...refinished a well rounded chine, and <b><i>then</i></b> applied a final layer of putty and tape on top of the (rounded) chine...to try to artificially
build up a sharper chine on an old round-edged boat. I got mixed results. The boat tracked better, noticably, from the getgo. But my triaglular "chine-sharpening" patch didn't hold up well. I'll have to re-do it this spring. I think this would have worked just fine, but I did a lazy job of it last spring, in an unheated garage. I'll soon have a gas heated shop, so I'll soon be out of excuses!


A few wiggles in the chine won't hurt. It will get a wiggle or two eventually anyway.

Gougeon Bros used to pitch graphite powder as a finishing process that
produces a "low friction finish." I bought some and used it until it was gone.
I never noticed any improvement in boat handling, so I don't use it anymore.

In reply to "graphite, and chines", posted by Tom

RE> tracking.

I might help to define tracking, if we're going to
talk about it. For me, tracking means the ability of
a driftboat to hold a bearing and/or an orientation,
with respect to some fixed spot (like the bank), despite
changing currents or wind.

This is mostly important for fisherman. If you want
to keep an even distance from the bank, or a from the
edge of a run, then you want a boat that tracks well.
Good tracking usually means the boat isn't quite so
nimble, and doesn't turn so quickly.

If your primary concern is running heavy, boulder
strewn water, you probably want a rounder chine, than
if you spend most of your time fishing.

Finally, old fashioned ribs and plywood boats
usually go beyond a sharp chine: they often have a long
1 x 2" strip screwed onto the chine, as a removable
bumper of sorts. I hate those things. They catch the
water so hard they make it very hard to turn the boat.
Worse, far worse, they will catch the current dangerously,
if you ever suddenly, unexpectedly get turned sideways
to a strong current. Boats like that do track very well,
but who wants it? Not me.