how to give a hull bow lift

[weehenry]

thankyou so so much for taking the time out to help me here i really appreciate the help

i forgot to mention that the boat goes about 6 mph faster going after the wind rather than into the wind it slows

i see a lot of boats have a pad bottom ie the fountian racing boats what are the benifets of this
does it help the bow by getting the shaft more horizontal

[Guest625101138]

A stepped planing hull can be lower drag than a single planing surface. The stepped sections act as individual lifting planes so suffer less induced drag because they are higher aspect than a single surface. It means there is less energy lost in pushing the water sideways.

If you Google "stepped hull" you should get information. There are threads here on this sort of hull as well.

Rick W

[tom28571]

Rick,

The heeling into the wind issue is common. It's caused by the boat being blown off course by the beam wind. Course correction is made by steering toward the wind. This introduces a heeling moment from the offset thrust used to hold the proper course. Thus the boat banks toward the wind just like it would in a turn.

Not as important with a surface drive since the vertical moment arm of the propthrust is very small.

[Guest625101138]

Originally Posted by tom28571

Rick,

The heeling into the wind issue is common. It's caused by the boat being blown off course by the beam wind. Course correction is made by steering toward the wind. This introduces a heeling moment from the offset thrust used to hold the proper course. Thus the boat banks toward the wind just like it would in a turn.

Not as important with a surface drive since the vertical moment arm of the propthrust is very small.

Tom
I know it is a common problem. I have never sat down and considered the forces involved. I appreciate the explanation. It also supports the point that you cannot ignore the force of both water and air on the hull, particularly when you are traveling at high speed.

The reduction in vertical moment arm with the surface drive would contribute to the bow down attitude. I think this has already been suggested in one of the earlier posts.

Rick W