X dimension and prop shaft height for 3's
 

Putting ssm3's on my 40' hawk, the transom is notched and I'm considering short staggering the motors. What should I cut the x at for a good cruise and decent planing? I don't need every last mph out of it.

Nothing?

someone must have an idea ? I was told by one person 3-4" below running surface?

I would say that's close.. Mine is 4.25 below the bottom and I get on plane just fine that's with a 32' boat you may need 5 blades in a 40'

Thank you!! Glad ingot some kind of answer, is your transom notched?

fixx
 

depend on the diameter of props your going to use..

i have a lead on some 16.5"x 26" 4 blades what would you suggest?

No I was going to notch the transom when I rebuilt the boat but I wanted a longer running surface so I opted to install extension boxes instead..

I couldnt get on plane with 3 blades after raising the x on mine!!

What kind of power will you have? that would really determine the pitch of prop..

depends if anyone buys my 174 blowers and i upgrade, as of right now about 590 each

As a reference point, our Mistress with SSMV's on boxes and 16.75x32 4-blade merc cleavers was initially set up with the propshaft centerline about 4" below hull bottom. No trouble getting on plane, 4000 rpm brought it right up. At this X-dim, it was really so deep that it would not even throw a tail. I've since knocked 3" of spacers out, but have not tried it out yet. If you don't have the boxes, I'd add an inch or two. Four blade props you can probably run 1" to 2" higher than a 3-blade.

A III doesn't have nearly the skeg of a V, so that might be a factor too. Better to keep a little more drive in the water to keep it from swapping ends on you.

Bigger, heavier boat, I'd lean on the side of keeping them a little deeper too.

Bottom line, for your rig 4" below is probably the right number. If you have the hatch clearance, you could mount them an inch or two high, put spacers in if you need them.

thank you for the input. i'm thinking of locating some 1" spacers and shooting for 3" then add the spacers to get me to 4" if needed