Hailing JB

[Bob_VT]

JB, could you please do me a favor?

Post the "theoratical speed formula" and then move this to the proper forum or maybe in the FAQ.

Thanks,
Bob

 

[WillyBWright]

Re: Hailing JB

Other formulae could also be good in the same FAQ including max horsepower formula (below), prop slip, Knots conversions to mph and kph, others that will be suggested. Leagues, fathoms... You know, Nautical stuff.

From Bostom Whaler...
(2 X L X W) -90 = [maximum] rated horsepower
[dimensions in feet like 14'6"=14.5']
Where:
L=boat length
W=transom width; if the boat does not have a full transom,
the transom width is the broadest beam in the
aftermost quarter length of the boat.

The rated horsepower may be rounded up to the nearest "5".

 

[JB]

Re: Hailing JB

The theoretical WOT equation doesn't work for everything, but here it is:

[square root of (HP/lb)] x bottom factor=mph

Bottom factor: deepV= 125-150, semiV=150- 200, flat bottom=200-225

HP is engine prop HP, lb is weight of boat on the water.

The theoretical WOT assumes ideal prop and rigging.

WBW, we need to include the transom height variable. I seem to remember that the USCG formula gives a plus for 20" or a minus for 15".

We are still working on making the Engine FAQs read-only, so let's wait until it is working as intended, then put together a FAQ for "How fast can I go?" and a seperate one for "How much power?"

 

[Bob_VT]

Re: Hailing JB

Thanks!!