Fountain 27 5-blade?
 

I just bought a 2005 Fever 27 with a 496 Mag HO, it has a Bravo 1 30P and I think the prop slip is way too high. Cruising at 3500 rpm, it runs about 33 mph with the drive trimmed to 3-4, top speed is about 66 mph @ 5000+ rpm... It barely stays on plane at 3000 rpm. I don’t know the drive height but I guess it’s standard. Drive is Bravo X 1,65. I’m actually not looking for higher top speed, more like good all-round performance and better cruise speed & fuel efficiency. But I guess it would be possible to gain a few mph with reduced slip. I would like to try a Maximus 28P. My question is does anyone have any comments on a 5-blade prop for this boat?

With a stock engine and a 27 ft boat you shouldn't need a 5 blade prop, there's something else wrong, have you checked the drive trim angle compared to the indicators on the trailer ?

I have the exact same combo in my 04 27 and it runs pretty similar. My cruse speed is like 35mph at 3500 RPM, 43 mph at 4000 RPM. Top speed is only about 65mph @ 5000-5100 RPM. Prop slip calculator says like 28% slip.

Performance report says 72mph @ 5100 which would still be 18% slip. Mine wouldn't run 70 anything if you threw it off of a cliff.

You have to use the tabs to get on plane ? Ive never owned your type of boat but did have a 272 baja 502 mag mpi and never had to use tabs.........have you checked the prop hub ?

Those numbers sure seem familiar... And I guess prop cavitation is familiar to you too? If you slow down for waves or something, say from 35 to under 30 mph it starts cavitating and takes a while before you reach you normal cruise speed again. Same thing if you make a tight turn, cavitation and almost comes off plane. I need a prop with better bite and I believe a 5-blade could do the job.

Don't have to, but I want to use them to keep the bow down. It goes on plane plane faster and smoother. I don't think anything is wrong with the boat, except the bottom might be a bit dirty. I think the step bottom itself causes higher prop slip especially at lower speed. But now the slip % is 25 at full speed also and that is something I find unacceptable.

Make sure when you do Prop Slip Calcs, that you have Accurate Data , GPS Speed and a Calibrated Tach , 99% of Tachometers are off by a large margin.
Good Accurate Garmin Speedo , and you can use a Scan Tool for a Tach reading , we check our tachs with a MSD Ignition tester.
If your date is Skewed you will have some goofy Slip numbers.

Have you measured the center of the bullet ( prop shaft ) in relation to the bottom of the boat in neutral trim ? the drive must be high

Mine acts 100% the same. If you drop the tabs to 4 at slow speeds it will stay on plane and the prop will bite better. If you leave the tabs up and try to cruise below 3500 RPM it will cavitate a bunch.

These boats need tab to get on plane. If mine is full of fuel and 4-5 people on board it takes full tab and just about everything the motor has to get it on plane.