crmax

I have a 99 20'wellcraft excalibur with a 7.4 mpi Ive hit 64 on the speedometer which is close to 60 on the gps. at top speed it chinewalks a little. any ideas on how fast this hull can go?

blown formula

If you are chinewalking now....you can only pull the trim in (drives down) to stop it ! This will slow you down fast!....Most boats cannot safely go faster once chinewalking is encountered. Most marine engineers say there is a "maximum designed speed" built into the hull. I have never been able to get one to tell me how that is arrived at or what it is for a given hull. Fountain tells you "learn to drive thru it!" That's scary & can kill or maim you or you passengers. A boat can practically turn around in midair and throw you out! Trim is the best fix I have found. I encounter chinewalking at 75 mph (gps) in my 252 Formula, so I would imagine boat length, weight, hull design, would determine top safe speed limits more than power. You can over-power a boat with an engine. It will sound great but exceeds the capabilities of the hull.

turbo2256

If you dont already have one a 4 blade prop might get more of the hull in the water and cut down on the walk untill a higher speed.

CayFomula

I have little experience with stern drive boats, however with outboard boats the speed at which it starts chine walking can usually be increased by raising the engine, so raising the drive should do the same. Obviously this only works up to a point so dependent on your drive height at present this may help. Another thing that can contribute to the problem is any play in the steering.

crmax

as I learn more on what it wants as far as trim I hope the chinewalk moves up the rpm range. I have no plans on putting a ton of horsepower in it but it would be nice to go over 70mph

Katdrvr

Is your steering loose? If there is even a little play in your steering, when the drive is trimmed out and the boat is "light" on the water the drive can wander side to side a little bit causing it to chine walk. Sometimes hydraulic steering can help with chine walk, by preventing the drive from moving side to side. I doubt it would completely cure it, but it would make your boat a hell-of-a lot safer.

mike

mike

[ 02-12-2002: Message edited by: Katdrvr ]

Kanookstr

Crmax, A prop has a lot to do with it as well. I have a Stingray 230SX with a 502.
Stock she came with a 25" Mirage Plus 3 blade.
She did 73 MPH on the GPS, but after 15-20 seconds at that speed she would walk. I now have a procharger at 5-6 lbs boost. I spin a 31" bravo 4 blade, (labed by York propellers) at 5300 RPM. I get 88.9 MPH on the GPS, and she's rock solid. No chine walk what so ever. Just going to a good 4 blade help steady the boat.
Good luck