Holy cow, almost 500 views on this thread.
I guess I should share a little tip I stumbled upon when it comes to making a rubber tiled hull look a little more realistic. Tiled hulls (above the water line) take on an odd sheen after they have baked in the sun for a while.
You can mimic this effect using India Ink and a brush or Q-Tip.
Start by painting the upper hull with a semi gloss Tire Black or, better yet, Testor's Black Chrome and let it dry and cure fully. The key is that the paint must have a semi gloss or semi matte finish (you don't want a full gloss or full matte/flat finish).
Next, grab a bottle of India Ink. Black works best but you might want to try brown ink for a look of aged tiles.
Using a small artist's brush, paint down a coat of ink over the paint and let it dry. You should notice the "sheen" effect at this point. If it looks right to you, stop at this point. If you want more of the effect, try lightly blotting some of the ink on the hull using the brush (better yet, try this effect on some painted scrap so you get the feel of how its applied).
DO NOT try to overcoat the hull once the ink has dried. You'll lose the effect.
India Ink over plastic and enamel paint is far from permanent but it looks "right" and is very easy to re apply.
As far as what brand works best and where to find it- experiment and look around. If you get the effect you want, you found the right brand.
Just make sure its ink like you'd use in a quill type pen. Make sure its as thin as water or even thinner. You don't want this effect to look "perfect" so don't worry about painting close to different colors or in seams.