Greetings to All,

I polished my Dupont Imron painted white hulls using Starbrite polish with PTEF. The process of cleaning the hulls and applying the product took four hours. A few weeks latter the sides of the hulls had dirty streaks. The hulls had small zebra stripes where water and dirty ran down the sides. I was unable to remove the dirty streaks using car wash cleaners. After trying many cleaning products, the only product that worked also removed the polish/wax. The Starbrite with PTEF is going in the garbage.

Does anyone have better luck with a different polish/wax? I use Classe All-In-One on my cars with good results. Should I try this on the boat?

I use NuFinish - a synthetic wax with a UV inhibitor. I still get the black streaks and they are difficult to remove. However, I wash the boat using a solution with a little soap and a little bleach - the black streaks come right off with the bleach. Twice a year I re-wax the boat. It was bought new in 2004, and although the trampoline remains tightly covered, the hulls get a good bit of sun exposure but still look new.

This may be old school.. but I had always been told that wax would actually slow the boat down.. That a lightly wet sanded boat was better, cause it would create tiny air pockets that would create less water resistance. Is this an urban myth?

Yes, I believe this to be an urban myth. A clean boat is a fast boat. And a clean and waxed boat seems to stay cleaner. I always use that Starbright with Teflon stuff. I've had good luck with it.

Mike Hill
Tiger #1520

Here we go again on the wax / no wax debate.

Popcorn, anybody?

The theory behind the "slightly roughened" surface having lower skin friction is that the small imperfections allow water to attach to the surface more easily, prolonging the laminar boundary layer (lower friction) before it becomes a turbulent boundary layer (more friction).

This is a real problem in model tank testing to the point that "turbulators" (small wires) are installed on the bow of the model to induce a turbulent boundary layer. Otherwise, the model is "slipperier" than it should be, throwing off the test results.

In reality, the frictional difference bewteen the two surface conditions is negligible on small catamarans. There are too many other factors affecting your boatspeed (sailtrim, boat handling) to worry about the skin friction of your boat. One slow tack will more than compensate for the difference in skin friction.

Additionally, the benefits of waxing the boat include UV protection, sealing the pores in the gelcoat (so the boat doesn't soak up tannins - brown stains - from the water) and it looks a lot better.

I've seen nothing but theory regarding this as it relates to detatched and/or laminar flow on a surface vessel - nothing tested and proven. In my, somewhat flow educated, opinion there is probably something to this to a fully submerged object like a submarine but as it relates to a surface piercing hull and it would have very little and unmeasureable effect.

If it actually made a difference, where is the tank testing to prove it? During the last America's Cup, one team had a clear finished carbon boat (I don't recall who that was). As the event went on and they didn't put up the results, you could see their boat get chalkier and chalkier as they resorted to wetsanding as a last ditch effort.

I think it's more of a wive's tale started by some theory that is better applied under other circumstances.

Jake, have you heard anything about a non-fouling film the Navy is using? The blurb I heard was that it has a textured surface, at the micro level, that prevents barnacles and the like from attaching.

I use McGuires GOLD. The thing, will clean any stains off and will leave a nice coat to protect the boat. I usually polish/wax my boat two or three times a year.

Yeah - but it has less to do with a coating that's efficient through the water than providing a long lasting barrier coat that will keep marine growth from growing and causing a lot of parasitic drag (pun). Traditional bottom paints can be harmful to the environment in large quantities and because they are sacrificial by design, they have to be recoated periodically - not a good option with something the size of a battleship.

NuFinish is my weapon of choice. Very easy to apply, lasts, and is dirt cheap (available in Walmart).

Chris.

You must of missed their other product, Black Streak Remover. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Waxing your hulls is just like waxing your car. Find the easiest product to use and you won't mind doing it more often and if the surface is new, a product with no cleaners or abrasives.

I would try the spray Turtle Wax. It comes in a green bottle. It goes on and comes off easy and leaves no white residue.

If you can find a sheeting wax that would be better. One that allows the water to run off instead of bead up.

My boat when finished will have a two pot marine paint surface. Any specific care ideas asside from gel coat?

If your into waxing, then what I said above.

If your not into waxing then nothing. If needed use a glazing compound like Mequires #7 to clean with. I think #9 is the same stuff for a buffer. These and for that matter any Glazing compounds are without silicone.

When you say 2 part paint I'm guessing a good Poly Urethane??