finding thrust

[scott steffe]

how would one figure out the trust power of a v 6 outboard say 300 horse power
anyone ??

[jehardiman]

Without prop data it is impossible. Rules of thumb say maximum thrust of 20-30# thrust per shp @ 0 speed and maximum rpm (n) dependent on delivered torque, falling off at some factor (dependant on the prop pitch to diameter and n^2) with the advance coefficient J= Va/nD. Usually, for most P/D ratios, thrust =0 at J ~ P/D.

[scott steffe]

so lets see if i get this
so using a prop caculater for speed you are figuring thrust ?
14x32 cleaver @ 6000 rpm = 145 mph or so giving what thrust ratio per lb
so what would be the trust power needed to turn that prop @ 2500 rpm
300/500/ 600lbs or more