I kinda thought 25's would be too much. The best I have seen with my 23 Mirage plus (stock) was 69.4 (gps), most of the time it is in the high 68's (gps).My boat was owned by a friend last year so I rode in it all the time but I really didn't pay attention to rpm's etc. I ended up buying the boat over the winter and have not had time to track sped and rpm.

From the post above I don't see how 31's could ever be used. Even with 25's 76 or 77 would be hard to believe. 25's at 4800 rpm with 0% slip (not likely) would be 75 mph.

tssteph,

The P-29 runs in those speeds because of the Blawkhawk surface drives. They are 7 inches shorter, and are spinning (2) 31 pitch props EACH in opposite directions. The first prop scoops the water and throws it into the second, which is a cleaver. The P-29 tested in Powerboat (1996) was running 4900 rpm at 76.7 MPH on GPS.

Fever Mike - FYI - measure the hull on a 29 Scarab and you will find that it is just a few inches shy of 29 feet, NOT INCLUDING the platform...

Thats impressive. Thanks for the info. I didn't realize there was that much difference in the Blackhawks.

There may be one available here with 550hp blown smallblocks and blackhawk drives.... mid 90's .... a wild ride.

I just bought a 29 with a new 540 ci engine w/Crane Rockers, and other racing parts producing 600 horses. I am anxious to get it out soon.

I just purchased a 1998 29ft with twin 350 mpi's and 23p mirage plus's counter rotating and with 3/4 tank of fuel and 2 of us max'd rpm was 4750 and non gps speedo showed 67-69 in about a 1-2 foot chop. thinkin about a 24p 4 blade labbed. any thoughts ? right now outta the whole is great and mid range is great fuel consumption seems a little strong though.

I tried some 4 blade Bravo 1 props, they did not work well at all. The boat really seems to like a lot of bow lift. My rpms are a little higer then yours but may be because of how much I trim compared to what you are doing. Your speed is about right and is probably pretty close. In some testing yesterday I ran 69.3 with half tank of fuel and loaded with gear. I just mailed my props to Houston Propeller for some work, I will post a new message when I get them back with the results.

i had her out yesterday...trimmed to the moon with ZERO tab and approx 60 gallons of fuel hit 71.2 on a handheld garmin...was a 1-2 ft chop and ran like the wind...still cant get rpm's over 4700...thinkin about havin my 23's labbed

If I trim way up mine starts to wobble real bad from right to left. If there is a cross wave it really gets out of control. 71.2 is not bad.

are you using any tab to stop the chine walking ? and which way are your props spinnin ?