brett did my maximus props . and they destroy my bravo s .. they just plain hook up and get you there . not like my bravos that took well longer to reach top speed .. must be my boat design and my higher x demention .. they dont seem to carry my bow as well . i believe they are a better stern lifting prop . but i know chit about props .. but i like my maxies rett i need 300 rpm more can you achieve this with a adjustment ???

It looks like th epost above yours by ericwinters was edited by a moderator, therefore I believe that response was for ericwinters, not you.

Did look funny !

Correct.

OK,
So I've got Bravos now with a high X, prop shaft is 3 inches below bottom of straight bottom hull, boat is an old Fountain 8.8 meter measuring just over 30' 6" from bow to transom. Boat came back with 28' Bravo 1 and now it will not plane with full tanks and the tabs down, have to have the tabs up to get it to fall over, and it just doesn't like having so much of the prop out of the water. Thinking a 5-Blade is the way to go 28" pitch. (with deep TRS, it would pull a 29" hydromotive to 4500 and 70 mph, and at 2600 it was hooked up and efficient at 30 mph). Comments? Running about 525 to 540 HP at the props.

Good luck. As with anything changing scenarios will need adjustments. Try Brett's program on props. I'd go with more bade surface if you're cavitating. 4500 is way to low rpm. Might want to drop a couple pitches. Maximus props are big mofos ,, you might have to drop several pitches to achieve rpm levels. The real question is you're slip numbers. That will tell you what prop to run. I love my Maxie's.

4500 was with one (1) sick motor (bad rings) run on 7 sometimes, had other issues to keep it from top speed, had drive set at '3' when it should have been at '6' with TRS, good engine carb grabbed bit of gunk in the secondary needle valve cut testing short, so the 4500 at 70 was just what it got to, and did not have time to test further as it was headed to the shop on that run. With drives trimmed, running on 8 both sides, folded Bimini's off boat instead of in the breeze, it would have pulled 5 to 55 rpm easily.

Brett,

When does it make sense to remove the diffuser ring? Is this more for planning than anything? I have a 30' cat with prop shafts even with hull so they are definitely surfacing. When I went from bravos to p5-x it was night and day difference in planning. I feel simply the 5 blades had this affect. I do have porpoise at mid range now and when accelerating. Too much bow lift? I talked with Bob leach and he said I need the maximus props for best results. I asked if I should use the short tube or standard version. He said short Tube. Then a day after that I talked with a fellow member here with almost same boat setup and he went with the standard maximus with great results. Sounds like the maximus is the way to go but don't which which style. Also I believe the diameters are larger than p5-x props. If so how much more and how does this affect pitch selection when comparing the two? Would it be a wise move to lab these props to a specific boat such as my daytona or are they geared toward my type of high x boat already in either model? Thanks!!!

Eliminated572,

These are all great questions. They also require a bunch of explanation and discussion. I would request you contact me at the office to discuss this in depth. I can cover more ground quicker that way.

But until then............
Diffuser rings were introduced many years ago for through hub exhaust set ups. The divergent tube created high pressure which isn't attractive to the high pressure on the prop blades and prevents blow out upon planning.

There up pros and cons to the diff. rings. Some cons are drag, stern lift and reduction to trim reaction. Some pros are better planning and stern lift.

The Maximus is 15 5/8" diameter out of the box. The P5X is 15" of diameter.

The diffuser ring/tube was not intended to be as long as it is when we began development in 2002. This development was a joint venture between us at Merc Racing and the main plant Merc Propeller Co. In the end with the large diameter and large rake angle we needed a long diff tube to aid in production. It was that or build new pouring fixtures for the foundry. Longer tubes was the best option at the time.

We have been cutting the tubes off the Maximus since the props inception. Mercury Racing decided to offer this as a actual part numbered option a couple years ago rather than a custom option. The down side is you only have one option. We offer various lengths of removal determined by the actual set up.

I've written volumes of information on these props on this forum over the years. Search back if you have time to learn more or call anytime.

Oh, by the way, the correct Labbed Maximus will most likely out perform the P5X.

Brett

Thanks Brett! I will be calling this week. I've been trying to search and the search feature on the forum has not been working the past few days....leaving me frustrated and lacking intelligence Talk to you soon

Brett will the maximus be faster than a p5 all around? not the p5x