Will a Hydrophobic Coating Make My Boat Go Faster?

[Diamond Chad]

I was at the store and saw the rustoleum never wet, and thought maybe I should get some.   Well, Not Really.  Here is a dry paper with some chemistry and physics around why.

pocock-floating-on-air.pdf

[David CVX-16]

I read the article fast and did not understand the technology, but some well known tricks to make a boat go faster are straight lines in the hull from front to back, sharp edges, no scratches in the hull, a buffed surface, and perhaps roughing the end of the hull with fine sandpaper to release the water better at the end of the hull. Some lower units have a rougher paint on them.

For boats in our speed range, probably the most critical is a straight hull without hooks or rockers, without scratches, and sharp edges on the stakes and at the end of the hull.

[Plugcheck]

The clear on my Z, at least the pad area, is wet sanded with 600, the rest is buffed.   Top speed so far was 61 mph, but with a 21p prop that could not hold the engine, 6500 rpm+.   Trying a 25 at red wing.   Not certain if hull finish is that critical to our boats and speeds, but I did sand the pad as recommended by most sites.

[David CVX-16]

One article I read spoke of different products to apply to the hull, mainly though for sailboats. But Rain-X was mentioned. Would somebody apply it, try it, and report the results?

[Diamond Chad]

That is how I read it, the most important factor is surface being smooth, with no bumps or scratches.  Since the water cannot bead underwater, the effect of the hydrophobic coat is nullified.

Since their hulls go slower than ours, (because they use oars), I don't think they were worried about the release.  The 600 finish on the back of the pad makes sense, and I had not heard that before.  Thanks for the tip.

[fireman24mn]

I have always heard the opposite and that a hull needs to be a little rough, like a golf ball.  Water/ air gets trapped in the little divots and water on water is faster than water on hull.  The other thing I have read is is if you take sand paper and make a scratch in the hull from front to back on the entire running/ wet surface of the hull. 

On my 23 I removed all the hook, sharpened the strakes, and transom edge. I am not going to sand or buff the bottom of the hull leaving a little orange peel.

[Diamond Chad]

Well, this article was written with low speed rowing hulls in mind.  Maybe the entire process they are discussing is not applicable above plaining speeds.

[OleRed]

slick and strait is better in my opinion, I never seen a golf ball finish on a 600mph airplane

However, if the boat goes fast enough to cause cavitation bubbles on the hull, like some props do on the back surface of the blade, then you could burn holes in the hull, like a prop can, let's see ... 3900 rpm on a prop blade = ? would be like 292 mph on the hull, extended periods --- that'll do it