Offshoreonly.com - prop slip

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I am running a JC Performance 598/800hp N/A, dynoed a bit over 800 lb/ft. A 29' Kryptonite weighs in around 5000lbs, or so I have been told.

Quote:

Originally Posted by Philm (Post 2917067)

I am running a JC Performance 598/800hp N/A, dynoed a bit over 800 lb/ft. A 29' Kryptonite weighs in around 5000lbs, or so I have been told.

That boat runs hard. Is it a step bottom?

Yes, single step. Pad bottom, full length lifting chines.

A stock 525hp will get it into the low 80's.

I have a boss hammer 21'6" I JUST PUT IN A 502 WITH 500HP
WHAT PROP WOULD WORK FOR MAX SPEED, WHEN I HAD MY 454 310 HP MOTOR THE BOAT RAN 64 GPS WITH 4 PEOPLE AND A HALF FULL TANK OF GAS. tHE PROP I HAVE IS A 23P.

I came up with 11% for my setup. Would this be too hard on my drive or motor. the boat is a 98 25 Active Tunder, with estimated 500hp, 489ci, 1.5 bravo one on a Stellings box with 1" lower spacer, 26 B1 wheel. Prop shaft is 2" below boat. 73mph at 5000 rpm. Im not real sure on the drive ratio, could it be something else?

Quote:

Originally Posted by articfriends (Post 2916216)

I ran my current numbers thru the slip calculator adjusting for the fact its a merc prop and its labbed and my slip is 18%-19% (currently 98.5-99 mph w/32 pitch merc labbed at 6100-6200 rpm's) but still the same I have lowered the wot slip and never had any kind of gain on top of trying a stellings box with neg results and a imco 2" shorty with neg results,Smitty
28% would be pretty high,I would be trying drive spacers and different props until you get the best overall balance of speed and driveability.

An interesting observation on slip... Gary Taylors TPI Howard Bullet, which is extremely fast, has prop slip right around 20%.

I have done an extreme amount of testing and data recording on different drive depths, and different props on my 28' Nordic Heat, and have determined that it runs faster and handles better with slip numbers in the 14%-18% range.

After spending literally hundreds of hours fretting over attaining low slip numbers (got them as low as 5.2%), I deciced to let those numbers go, and concentrate on overall speed and boat handling. As a result, my boat is now faster, and handles better than ever before.

91-92 mph consistantly. 730hp out of a Whipple upgraded Mercury 600sci

Best speed to date: 94.1 mph, 1.504 gear ratio, 5900 rpm, 30 pitch p5-x labbed by Herring, 15.5% slip

Just my observations,

Chris