what do these "steps" near bow do?

What do these "steps" near the bow do? Do they have another name?

(please click thumbnail to see the "steps" I'm asking about near the bow)

 

They ventilate the hull to decrease skin friction.

 

Gonz, Easy to see what they do but it looks like there is probably a bad side effect. These steps will likely be constantly going in and out of waves in rough water so they will be alternately ventilating and sealing off the air inlet, especially on the lower one. Not a good thing and might make for some bad bow steering issues when one side seals off and the other ventilates. Maybe that doesn't happen but I'd want to see the tests.

 

The first boats I used with that design type surprised me with their good handling. I thought they would be unpredictable in a chop, but was mistaken.

 

Interesting that you did not find any bow steering effects from the steps. Proof is in the actual experience, initial opinions notwithstanding. Have you seen any data that shows actual drag reduction in normal use?

 

No. I can only say that the handling was really good. The hole shot seemed a bit faster than comparable boats with standard bottoms, but it could just be that the boats were new.

 

Thanks! Do any other boats have these small "bow steps". How long have they been around?

The boat pictured above is a sunsation.

I had not seen these before.

 

The original "shingle bottoms" are from the 1920's.