hull wax

[alorio1]

I am curious to know what everyone is using to wax boat hull (bottom side mainly)............I was looking for a wax or friction reducing agent to apply to the hull to reduce drag. I have optimized the prop for best speed but I still think the boat would run faster if I reduce drag. The boat is a 18 ft. 135 hp Mercruiser (chapperal)and tops out @ 42 mph. Im not saying this is not inadequate speed for this setup but I would like to experiment with this vision/idea that the boat may go faster if I do this wax/friction reduction thing. This is my first boat to own so I am definately new to boating.........thanks in advance for any recomendations of product or products recommended.........Joe

[Rachel]

Well, 42 miles per hour is a bit out of my league, but at least on sailboats, waxing the hull (below the waterline) will actually make them slower. Perhaps some aeronautics/physics types will chime in, but it has something to do with how the water flows past (laminar flow?).

I think that's why racers sand their hulls instead of waxing them. Along the same lines, I once read that for optimum gas mileage, an automobile's surface would resemble a golf ball (I comfort myself with that thought every time someone opens their door into the side of my car, or we have a hailstorm...).

FWIW --- Rachel

[Jason K]

My understanding is that turbulence actually helps a hull move through the water. The smoothness of the waxed hull does not create any friction and, though it seems counter-intuitive, allows a stronger bond between the water and the boat. Alternatively, a wet-sanded hull will have some friction and will create a small degree of turbulence. This turbulence interrupts the water's bond on the boat and allows the hull to move through the water more quickly.

Of course, I'm not an expert; I own a Triton. If I wanted to go fast, I would have bought a bass boat. Dem sparkles just mesmerize me [redneck accent].

[bcooke]

I think that's why racers sand their hulls instead of waxing them

Interesting.... a racing type sailboat came into my yard the other day with some sort of graphite bottom paint which would run counter to the turbulence theory. It is super slippery. What makes it all the more precarious is that its sharp fin keel can't carry much weight so the jackstands end up carrying the load. The boat is constantly threatening to slide off those jackstands.

-Britton

[Figment]

The whole wax vs. wetsanding argument is just a continuation of lapstrake vs. carvel planking.

The thing is.... at 40mph speeds, not much of your hull is left in the water anyway, so wind resistance starts to play a much more dominant role. Lash down the bimini.

[Tim]

The whole "turbulence" thing, as it were, is at a near-microscopic level. That graphite-type paint (probably Baltoplate--brownish, what all the cool racers use now) is wet-sanded with extremely fine papers, such as 1500 and possibly finer, to acheive that very smooth surface. However, were you to look at the surface closely under magnification, you would of course see the scratches that promote good laminar flow by actually allowing water to form a sort of "layer" against the hull, against which the water actually flows.

It's not so much turbulence as it is allowing this layer of water to "stick" to the hull, allowing the hull to slide more easily through the water by reducing friction.

It's so much easier to be a cruiser.