i just ran thru the calculations out of dave gerr’s book “the nature
of boats”. the suggested combination would be 16 x 11 for the
3gm30f. if you are overrevving you need to increase pitch, not
decrease it. my boat now has a maxprop, but the prior owner started
with a fixed michigan wheel 3 blade 16 x 11, repitched to a 16 x 10,
then repitched it back to 11. unfortunately i do not have
performance info with these various combos. maxprop recommended
setting the pitch at 11 on the new prop, although i do not reach full
rpm. i am curious if i goofed when i set the pitch on it and will
check it when i am next out of the water. i ran aground in georgia
on the icw, wound up high and dry for several hours a few months ago,
and should have checked it then.
john churchill