Prop me up

[aussiepontoon]

Hi all still trying to sort out these prop issues... now I believe there are props that are designed for pontoon boats and your regular ski type prop wont work.. as I am experiencing ...I currently am trying a 24p bravo 4 blade prop but it is still spinning its brain of with no grip .. it does help a little when I have a couple people stand on the transom .prop blowout is worse turning right than left but even in a straight line it still slips a lot....I am running a 5.0 EFI Mercruiser with a Alpha 1 drive with a ratio of 2.00... and the best I can do is 4500RPM at 24MPH .don't want to rev it much more....I need to bring the RPM down and increase speed ...Pontoon is a 24ft Harris Flotebote ....HELP HELP before summer ends...5 days in a row above 125F Damm hot...Paul

[HandymanHerb]

You should be some where around a 15 pitch, a 22 is for a ski or a bass boat

[MH Hawker]

Common pitch for a toon is 7,9,11,13,15 most use a 11 or a 13.

[Woody]

.. it does help a little when I have a couple people stand on the transom .

Considering this, and your prior post, I think your outdrive is mounted too high. Lets see some pics.

[aussiepontoon]

Thanks for the help... So need a smaller pitch prop ...this is where I get a little lost ...larger diameter in size larger ear size but smaller pitch size...is this correct ...does anyone have a prop in mind...I have read Mercury have released a new pontoon prop the Inertia Eco ...has anyone tried this ...again what size and pitch...Paul

[Shopguy]

I'm running a 14.75x17 on a yamaha 150 fourstroke and my boat is a 24ft tritoon. It'll turn 5400rpm with just me and down hill from there with the family. I also have a 15x15 that works great with the family on board keeping the R's at around 5400. Gps says 40mph with 6 people on .

Rule of thumb for pontoons. Measure from the prop shaft to the bottom of your cavitation plate and run the biggest prop you can, then pitch from there. Enertia and Mirage are good for this if your set on Stainless. Powertech has a line of pontoon props.

Bravo and Black Max, Solas are good aluminum props.

Blowing out in turns is usually from "bad" or turbulent water washing under the back of the tunes. The Hydro foil type fine does help with this along with big eared props.

In the end if you notice a difference in performance when people move to the back of your toon, well, that's a given in just about every case with a pontoon boat. The thing to look for if you really want to do something about it is too look at the centerline of your cav plate on the lower unit. It should be close to the bottom of the toons at full down trim. Compare this to other boats and you'll see a difference in them, but the cav plate has to be close to the bottom of the toons for your prop to stay in good water.

In my case I won't drop my motor any lower and live with the prop slip in a turn. I just deal with it.

good luck

[tuned]

Hey Paul. Sorry to hear that you are still struggling in the good season. I am struggling in the bad season. Just got done with a stretch where we bottomed out at -42F! By my math, that puts us at ONE HUNDRED AND SIXTY FIVE DEGREES APART! Unreal

I stand by my earlier advice in your initial thread, which has been stated here as well:
Before you beat your head against the wall changing a thousand props and not getting any good results, you MUST verify your mount and height.

If you can, please post several shots (on the trailer) with the camera held at about the height of the cavitation plate. This will tell us volumes and should be your top priority.

Once we know that you are at the right height and have a clean flow of water, then you start propping, not the other way around.

You have mentioned gearing. The more I think about it, gearing could certainly be a concern when related to your RPMs. I am sorry to admit that I am pretty weak in this area. Somebody here should be able to chip in on the subject.

Knowing that this is some sort of 'refit' also makes me ask about the specifics of what happened.
1. Is this an outboard transom modified for an I/O? Or is it a factory I/O transom?
2. Is it a 'pod' or in a tube? Is the tube full length? Once again, pics are extremely helpful here.

Good luck, mate.
Todd