Taking some measurments....X Dimension

[Last Real Texan]

Well in my quest of finding the right prop for this boat 97 27 ZX step hull, I was advised by Julie at Throttle Up props to do some measuring. Well I had her on the phone and was doing the measurements. I took a stright edge off the bottom of the keel with the drive trinmmed paralell with the keel and measured to the propshaft center line. The result 8 inches, she said no good, this put my lower cav plate 1/2 inch above the keel line and I was told now I am dragging this through the water also. Now she has advised me to put a 2 in shorter drive on it to get a little more efficiency out of this set up....... none of this makes any sense, I can already blow the prop out with the throttle ,would making the drive higher worse? .................................................. .. Help!


Now I am really confused .........Fast trucker where is your drive in relation to the bottom of the keel?
Anyone else care to help......

Bryan

[RickSE]

Hard to say for sure since yours is a single but I would be reluctant to go up on the X with a stepped bottom. The stepped boats will pull a lot of air in under the hull during hard accelerations & will cavitate the prop. It may end up being faster on the top end but I'd think that raising the X would have a negative effect on handling and acceleration.

Fasttrucker is probably the best source for 27'-28' single info. He seems to have his dialed in pretty good.

[The Hedgehog]

I have heard that the 26ZX is 5" (in a post from Bryan Tuvell). I do know that this hull is somewhat different. His post talked to the folks at IMCO who said that he would receive limited benefit if the distance was less than 7". Maybe you should talk to them and see what they say.

I would probably get the blow-out situation resolved with a new prop first. One observation that I had in your boat a couple of weeks ago is that once you burned off a bunch of fuel the blow-out stopped. I wonder if the lower weight had an effect on your angle of attack.

For grins I will measure my 27 non-step when I get back home. You got me thinking on that one.