prop questions for my 38' fountain
 

just repowered my 2000 38' fountain it has small steps and side by side all aluminum Paul Pfaff 700 EFI's. Just rigged xr's with imco-2's my X-dimension is 17 in. and my hub is about 3in. below the hull. what props should i run? I've tried 32 maximus 5 blades as well as 29 maximus 5 blades and im getting 57 to 5900 RPM but only 86 MPR top speed, although i didnt hold the rpm for much more than a couple of seconds it seems to be bow heavy. Maybe losing 300lbs in the rear keeps my stern high. any thoughts?

If your X dimension is higher than it was previously, you have lost some drag (good) but also lost some leverage for lifting the bow. (bad) Also, I believe the 5 blades will lift the transom, as well. Which props gave you the rpms/ speed you listed? 32 or 29 ?
Carder

i ran 32 b1 4 blades 5600 at 85 mph. i ran 29 maximus at5700 at 87 mph and feel the boat starting to gain more speed but didnot hold throttel. the32 maximus felt the best so far the mid range was strong but still no bow lift .the boat started with hydros 28 and i allways had alot of bow lift someone said 32 hydro 5 blades work good on fountains

The Hydromotive P5 is more of a stern raiser, and the P5-X is designed to help give additional bow lift. Tom at Hydromotive is very helpful with set-ups.
Not sure how the Maximus compares to the P5-X for bow or stern lift.

Carder

thanks carder
all the props have cups my hole shot is good

Ajusting the Lab process of the Maximus to decrease stern lift and add bow lift is a great option. All 5 blade props will add stern lift over 4 blade props. Making the correct modifications to the stock props can give the best of all worlds.

brett i ran my boat on sat with 29 p5x at 5700 got 90.5 mph the best mph so far but i needed trim way up to 6-7 . hydros seem to bee
the best for this boat will 4 blades help my slip.

If you decide on the P5Xs, Brett does a good job labbing. I never tried the Maximus, but my 35 single step seemed to like the P5Xs, especially after Brett worked his magic.

I have a 1998 38 fever t 700hp with imco -2 lowers. Best prop was a 29 hydro 92mph @ 5800. I am in the marine buisness & being a Merc & Hydro dealer I had opportunity to try all 4&5 blades on the market. With the prop shaft 3'' down you are still deep. A 4 blade is probably best choice. Best all around was a 30 bravo 1 from Bblades. Last year I repowered the boat with t850 Supercharged motors it's now running 103mph!

38, your slip is 13.27%. Not bad. I am surprised it isn't 1-2% lower. This is most likely to the over trimming required to get the R's up.

4 blade propellers usually do not help high slip numbers. However, a slightly higher slip number with the decreased drag the 4 blade gives you, may be the fastest top end propeller. Especially with the correct cupping and the fact that your X isn't over agressive.

Your desired RPM level and utimate goals now come into play. (speed or cruising/economy)