Stainless for a multipurpose boat

[Rancherlee]

I've got a 70hp 4stroke Johnson on my boat (Suzuki rebadge) and It came with a 13x17 prop. This engine takes V4 props with a 2.42 gear ratio. With this prop I'm hitting the rev limiter @ ~37-38mph when I run empty with one person aboard. I'm looking for a good stainless that would work well for a Fishing boat that is also used to pull tubes around. The boat weighs around 1200# with the motor, 3 batteries, and 12 gallons of gas. Hole shot and bite are my main goal without hitting the rev limiter with just me aboard, though I usually fish with 2-3 people.

 

[tommays]

Re: Stainless for a multipurpose boat

The thing you have to look out for is that it is BAD for the motor to NOT be able to reach its WOT with a full load (3 people )

When the motors are in the small HP range this happens much faster as weight is added

So the question is were are you with a normal load

Tommays

 

[Silvertip]

Re: Stainless for a multipurpose boat

Make sure you check engine height before buying props. If the AV plate is flush or below the bottom of the boat, you should raise the engine one hole at a time to determine optimum setup. Then go after the prop. If you have to have only one prop, you might consider a four blade stainless in an 18P. The four blade will bring the revs down a bit and should provide good bite for hole shot and towing. Speed probably will not change much. Work with your prop guy. They often let you try several before you buy.

 

[Rancherlee]

Re: Stainless for a multipurpose boat

Engine height is where it needs to be, 1/2-1" up from the bottom of the boat (any more and I can't trim out more than 1/2 way). I'm mainly looking for suggestions on brands/types that would work best for me.

 

[Rancherlee]

Re: Stainless for a multipurpose boat

Tested a 13x19 omc aluminum now.
5300rpm @ 34-35mph

put the 13.25x17 omc aluminum back on at the dock and it still tickles the rev limiter while running ~37mph. Picked up my friend and filled the livewell with the 13.25x17 on the back and it still pulled 5800-5900rpm @ 36mph without hitting the rev limiter.

this is with the motor as high as it will go on the transom, about 1" above the bottom of the boat. Both of these props will blow out at 1/2 trim (on the trim gauge) which is right about where it will porpose.


I got a great deal on a used 13.25x18 3 blade Turbo stainless and its on the way to test out.