Good information, Jay.

I'd heard that graphited surfaces left black marks everywhere, but was assured this was not the case from the folks at WD. That and the notion that there will be no friction to aid holding the boat in car racks and future repair complications is enough to make me shy away from it. I am terribly paranoid about strapping boats on cars. I could think of ways to negate the need for friction, but that just makes loading and unloading more of a bother.

The part about "Got Glide" is intriguing tho--who doesn't want better glide?! But not sure it outweighs the negatives. Maybe if I build a surf boat one day, it will be time to test the graphite.

Incidentally, I am having absolutely great results from my glassed and painted hull on my Anuri 16. I have a *heavy* layup of glass along the entire keel-2 to 4 layers (additional on ends) of 6oz tape over the 6oz cloth used on the hull. Brightsides paint. I have few surface scratches and no gouges after a summer's surfing on coarse sand beaches and running over logs in the river. The paint is worn off the keel at the stern where it begins to curve up, and mostly gone from the same position at the bow, but no damage to glass. Not exactly the most demanding obstacles, but my polyethelene boat hulls are all gouged up from the same conditions. Then again, I've been careful to mostly avoid oyster beds in the wooden boat whereas I remember a few significant scrape overs in the plastic boats.

Probably no need to complicate matters with graphite on the SK S&G.

Thanks again for the heads up.

: I have applied graphite/coloidal silica (same as cabosil)/epoxy from the
: shear down on my AT14 for the last two years. I typically use 2
: tablespoons in my 4 ounce mix (3::1 hardener), though I have tried much
: higher ratios. Initially I did it for anti abrasion purposes but was
: dissappointed that I saw only degrees of improvement, but yes there is
: definately a reduction in gouging and the boat glances off from most
: impacts. The bottom still required routine inspection and repair of deep
: gouges.

: The second year I incrementally sanded the graphite to an unearthly
: frictionless slickness and enjoyed increased speed (0.5kn @ speed/length
: ratio of 1.7 on 12.4' WL, paddling effort is subjective, your mileage may
: vary) and agility. Resistance wise graphite/epoxy acts more like epoxy
: until you start smoothing it (I wet sanded 220, 400, 800, 1200, 1500, and
: 2000 grits, then compounded and waxed). First, you have to be more
: carefull strapping the kayak on top of your car because now there is no
: friction between the minicel pads and the hull. Then, when you lay it down
: on a rocky or pebbly beach it will slide into the water by itself.
: Sometimes a frictionless surface can get downright frustrating! But then
: in the water... Got Glide? Turns and catches waves easier too.

: The first problem with graphite is the black gets on everything unless you
: have waxed. The second problem is that later when you add a layer or do a
: repair there is no chemical bond to rely on and since graphite is itself a
: lubricant the mechanical bond is weak. So, when you hit a rock the area of
: the strike or gouge will chip and delaminate. By the way, graphite powder
: is just pencil lead dust, and its not black, its grey like a pencil (it
: looks black when suspended in epoxy, before any sanding, and wax makes it
: darker too.

: I would say that racer ought to use smoothed graphite, or a paddler that has
: trouble keeping up with a group, or if you need to coax a few more miles
: per day out of your boat. But in general it is probably a lot easier to
: maintain and repair some other substance.

: I am not planning on using graphite on my next build (S&G NH), its just too
: messy and hard to maintain. I'm probably going to paint the hull black
: with some marine paint that doesn't require a positive pressure mask and
: leave the deck bright. The lay-up will be 4 oz S-glass doubled on the
: football. I actually bought Dynel for the football but I hear it soaks up
: epoxy and is therefor heavy. I believe the S-glass is even lighter than
: carbon fiber since CF retains epoxy as well (unless vacuum bagged or
: autoclaved).