My prop depth is about 3-1/2" below bottom. I also have CMI sport tube headers that gains a bit and Gibson Bullet mufflers that robs a bit.

You should also check the straightness of your bottom! I have put quite a few hours on mine to get it straight and sharp.

Measured the distance from bottom kiel to prop shaft is about 10.5 inches!

Based on your set up i guess it is way to low?

:eekdrop: 10.5 is deeper than mercury recommends for regular non performance boats. that would put you cav plate below the bottom. there is major drag from your set up, I would guess that you are giving up at least 10mph if not more. those are bravo 2 like prop depths, are you sure its not a bravo 2?

drive is a bravo 1 x . went to measure and check again just to make sure.
http://i1062.photobucket.com/albums/...1123-00092.jpg

Hmm it doesn't look like 10.5 deep, looks more like 8.5 or so but either way that's too deep imo, look at the example set here his boat is working well at 3.5 under

thanks prof, and you are right about the depth of the shaft, second time measuring i had the trailer accomodated in order to completly lower the drive, it was about 9 inches.

so, what are my options? my first thought would be to move the whole assembly 3-4 inches up and also a shorter lower unit. thoughts?

Sounds like a good plan, just make sure the bottom is straight, no hook sorry for the :hijack: But this stuff should apply to most straight hulls. And again tomas_wallin thanks for sharing it shows there is a lot to gain with straight bottoms by setting them up to take advantage of current prop technology, and taking time to tune the hull

That scag wan't work if You rase the X.

scag 67 up, 45 down
abbreviation of 'scumbag' meaning exactly that, or lowlife, cad, overall person of ill character. useful when avoiding expletives in potential road rage situations, and also used in 'Mad Max' the movie.
driver : that scag just cut me up at the roundabout!
passenger : yeah he was driving like a scag!

Nope, that will not work on a high x dimension drive:))

When you guys do the measurement is it with the drive trimmed all the way down or trimmed at wfo ???? And what are your options? obviously raising the drive but anything easier