exaeh007

I have a 26' Tunnel and suspect that given power vs speed I get, I have bottom problem. At 740hp it ran 97(GPS) and now with 965hp it maxes out at 102. Seems like with that much more power I should have seen more speed. When it hits 100 it seems to "hit a wall". Even turned the boost up, went to Av Gas, guessing I was pushing 1150hp and still could only get 105. I think I have a bottom issue and as I am located in Ohio, Cleveland area, was wondering if any of you know any bottom blueprinters within 200 miles. Any help would be appreciated.

Sean H

what kind of drive/prop are you using? what brand of boat?

exaeh007

Its a 2001 Force Offshore and I am using a Bravo 1 prop. Currently using a 32 but have tried 28,30 and 34.

glassdave

cats dont really respond to blueprinting as well as V hulls. never no though . . .what kind of shape is the running surface in? can you see any hook or rocker?

exaeh007

This may sound stupid but I don't know what to look for. How do you identify hook or rocker? I was told buy a friend with a 36' Spectre that my steps are not right?

glassdave

hook and rocker have to do with the trueness of the runing surface. if you look down the bottom of the boat with your point of view so you can "gunsight" the straightness you may see the surface near the transom as either a concave or convex. concave is hook and convex is rocker. this greatly affects the boats attitude if it is not right. it is more critical with V hulls than cats as your boat relys on the air in the tunnel to do most of the work. are you trying to correct a handeling problem or a speed issue? also do you know if that is a copy of an existing older hull or unique to Force, i'm not directly familiar with the brand.

exaeh007

Dave, I would not be surprised if the hull is copied from someone but not sure who's it would be. The sponsons are not as tall as a Spectre or DCB but it has a center pod like a DCB. I am trying to solve a speed problem. One friend at the lake is running 700hp in his 28 Profile and is 5mph faster. Heavier boat, over 250hp less and yet faster. This SLUG should run better.

exaeh007

I am in Ohio now, boat is at my lake house in Virginia. I will be there for the July 4th holiday and will look at the hull. Boat is in a lift so I will raise it up to eye level and investigate the bottom. I can even take digital pictures if it will help.

glassdave

have you looked into the drives X dimension. possible your drive is to deep in the water. thats always a great source of performance gains

Sean H

gear ratio of the drive? are you pulling the rpm you want/need? i would nail down the mechanics of the boat before working on the bottom of a cat, like dave said, very little of it should be in the water at those speeds anyway... dyno motors? HP peak? with that kind of HP you should be in the 120 range i would guess... how much do you have to trim it out to get that speed? that might give you a hint at your X dim.....??