Pontoon Prop

[bruceb58]

I have a 2006 21' Suntracker with a 90HP fuel injected Mercury that I recently purchased. I will be using the boat at a lake at 6700' elevation.

Current prop is a 14 x 13P model number QA2832X13P.

My plan is to bring it up to the lake to see how it works but I will likely need to drop some pitch.

My understanding is that Mercury makes some BlackMax props that are special for pontoon boats. Supposedly, they are double cupped. I am thinking I would get one of these if I ended up dropping to a 14 x 11P. Anyone have any experience with these props?

 

[jestor68]

Re: Pontoon Prop

Additional cupping adds effective pitch and may help reduce ventilation.

So your thinking is correct in the need to reduce pitch to account for the added cupping.

Mercury claims their "best" pontoon prop to be the "Spitfire pontoon". It has larger round ear type blades compared to the regular Spitfire prop.

With an estimated 18 hp lose at that altitude, it may or may not be necessary to change pitch.

As a point of comparison, I ran a 24 ft Tracker barge with a 90 Merc with a 15 pitch prop and turned 5200 rpm, which was fine for that 2 stroke motor. The Mercury selector says you should get 5500 rpm with your 13 pitch at altitude.

I guess you'll just need to try it and see.

 

[bruceb58]

Re: Pontoon Prop

Didn't know about the Spitfire. Will now have to look into those as well.

You have experience with these props?

 

[jestor68]

Re: Pontoon Prop

I have no personal experience with the Spitfire pontoon prop. The regular Spitfire performas about the same as other 4 blade aluminum props.

Merc is the only one ( I think ) to make a pontoon specific 4 blade prop. It costs about the same as the other 4 blade props.

If I still had a pontoon, I'd check one out.

I saw a couple of the Spifire pontoon props on E Bay; an 11 and a 13 pitch. Look at the photos and see the difference between the blade contours of the pontoon prop compared to the regular Spifire.

 

[Rkrough]

Re: Pontoon Prop

Michigan Wheel has a new Vortex prop 4 blade 14 x 11.(PN#941411) I just ordered one for my Evinrude/Johnson. $85 plus $40 for the hub. they list it for Merc also. Page 22 in the catalog, http://www.miwheel.com/uploads/resources/99021214_-_Michigan_Wheel_2014_OBSD_Propeller_Catalog.pdf

 

[j_b_5_2]

Re: Pontoon Prop

I have an 05 24' tracker with a 05 90hp merc. I have a 13, 15, and 17. The 13 pitch is too low. High rpms, no top end, and wastes gas like crazy. I prefer the 17 with 4 or less people and the 15 with any more people. You should be good with a 17 pitch for the 21 foot boat but you will just have to try it and see. I would not go any lower though.

I have a 2006 21' Suntracker with a 90HP fuel injected Mercury that I recently purchased. I will be using the boat at a lake at 6700' elevation.

Current prop is a 14 x 13P model number QA2832X13P.

My plan is to bring it up to the lake to see how it works but I will likely need to drop some pitch.

My understanding is that Mercury makes some BlackMax props that are special for pontoon boats. Supposedly, they are double cupped. I am thinking I would get one of these if I ended up dropping to a 14 x 11P. Anyone have any experience with these props?

 

[bruceb58]

Re: Pontoon Prop

I have an 05 24' tracker with a 05 90hp merc. I have a 13, 15, and 17. The 13 pitch is too low. High rpms, no top end, and wastes gas like crazy. I prefer the 17 with 4 or less people and the 15 with any more people. You should be good with a 17 pitch for the 21 foot boat but you will just have to try it and see. I would not go any lower though.

Interesting! I need to try this prop I have up there before I buy any thing.

The prop I have is a BlackMax version. It is not the pontoon version of the BlackMax which has an extra cup to it.

Thanks for the help on your very first iBoats post. Welcome!