too slow

[Chris Dean]

My 21 ft pontoon is fitted with a 4 stroke 90hp merc, wot gives me 24mph by gps at around 6200 rpm, from 5,500 up the speed does not increase only the noise. Any ideas on how i can get more speed? can't get up onto the plane maybe a fin or any way to get more HP from the motor

 

[Silvertip]

Re: too slow

Pontoons are not planing hulls and at 24 MPH it is planing (sort of) as much as the design will tolerate.

 

[steelespike]

Re: too slow

First of all a pontoon doesn't plane. Your in the ball park for speed.Carefully adjust trim and weight placement.A 4 blade pontoon dedicated prop may help.
If your not experiencing any ventilation(cavitation) you may be able to raise the motor a hole at a time to a point just before venting becomes a problem.
You can get a skin to go over the underside to smooth it out.There is also
an add on center pontoon like device that assists planing and handling.
Unfortunately speed is not a pontoons strong point; roomy,smooth stable ride and very versitile layout possiblities are the pontoons strong point.
For those who don't mind speeds below about 10 or 12 mph the pontoon will deliver mileage close to or better than planing hulls at the same speed.If you gain a couple of mph be real happy.

 

[gbb]

Re: too slow

your lucky to getting the speed you are. I'm am only getting 15mph an just enjoy the comfort

 

[Chris Dean]

Re: too slow

Thanks for the replies & suggestions, I was told that sun tracker have what they call NV performance hulls - if these were fitted I should get around 38 mph with my current motor/setup, having difficulty getting specs or drawings of them though. I'll try the 4 blade pontoon prop and let you know how it goes.
I have finally fitted lifting strakes or as Sun Tracker market them NV performance hulls, this was done by pictures from the internet and one helpful owner here in Australia, strange isn't it that a forum such as this couldn't give any help and only a few positive comments.

I'll let you know what speed I get.

 

[TexMojo]

Re: too slow

To me, Toons plow thru water versus planing. I have never owned one but have had friends who do. 24 sounds pretty good to me with a 90.

 

[tashasdaddy]

Re: too slow

i have a 1987 20ft 140 hp Evinrude, alone 37 mph, as you add more people, it drops quickly. and no sharp turns.

 

[cc350]

Re: too slow

Skinning the underbelly will add a few mph, lift strakes a couple more mph adding a 3rd toon or a waterglide a few more. But if you want more ya just got to have a tri-toon with lots of Horsepower. My 22ft pontoon did around 22-24 with a 90hp we skinned the underbelly and now we top 27mph. Was thinking of going up to a 115hp but I didn't buy a pontoon for performance it was a comfort and elbow room thing.

 

[Silvertip]

Re: too slow

38 MPH with a 90 HP 4-stroke is out of the question unless you spend serious money and even then it will be a stretch.

 

[jayboy73]

Re: too slow

I just finished rebuilding my 1982 24' Landau toon. Put a 2006 60 HP high thrust (geared for toons) with a 4 blade factory prop on it and with GPS and 3 adult men on board I got about 21 mph. I was running it at 5400. The Landau has the flat top pontoons, U shaped, and foam inside which over the years gets heavier with water. Thought that was pretty good. With 4 adults and 2 kids I only lost about a mile per hour.

My trim has almost no effect down or all the way trimmed out. Not cavitating but think I should go about 1.5 to 2 inches lower on transom and see if that makes any difference. I will have to notch the corners of the transom to get the motor bracket to go down to rest on the top of the transom. The old Johnson 70 I had on it seemed to have some affect when trimmed out. Oh yea there is no furniture on board except the plastic yard chairs we set up when cruising. My son and his friend both load the boat up with bags of tackle so heavy I can hardly lift them.

Based on my experience 24 sounds a little slower than I would expect out of 30 more HP. Of course the high thrust Yamaha and 4 blader may make a lot of difference.

 

[gill]

Re: too slow

get a bigger prop, you are turning too many rpm's already.

 

[lakegeorge]

Re: too slow

We have a 21ft toon with a 60hp 4 stroke Yamaha and get 21 by GPS, a 90hp should give you more speed than your getting. I would consider a prop change.

 

[ENSIGN]

Re: too slow

I've never heard of a go fast pontoon boat,you may want to check out the I boats used boat site