Stainless steel prop

[foxer]

I have 20ft Thunderjet outboard with a 140hp Suzuki. I currently have a 14x21 alum prop. Seems like conditions have to be perfect to hit 6k rpm (only once, with just me and full 50g tank). If there is any chop, I'm limited to about 5600rpm Would going to a stainless prop give me any more "oomph" or should I go down to a 19" pitch prop.?

[crabbait]

Yes, a stainless prop is more efficient because the blades don't flex like aluminum. With my 140 Suzuki, I was running a 19 pitch aluminum and couldn't get more than about 5000 RPM. I dropped down to a 17 pitch and went to stainless and the RPM jumped to 5600 (this is fully loaded for tuna...max weight).

You may get what you need just by going to stainless. If you drop down to a 19 pitch and go stainless you should certainly be there but you may sacrifice some performance.

[blubeast]

Current issue of Trailer Boat Mag has a side by side comparison of different props and their performance impact.

Just got mine yesterday in the mail. You may want to check it out.

[Starfish]

Typically you'll get better performance with a stainless prop but you almost always lose a few hundred RPMs if you stay with the same pitch. You'll likely want to switch to a 19 or 20 pitch prop in stainless. One thing that you might be able to do to counteract it is to raise the motor on the transom by a hole or two, putting less motor in the water. A large diameter, highly cupped prop can often hold at higher transom settings and boost RPMs (and speed). Best suggestion is to see if your boat dealer has several props they can loan you until you find the one that works best for your load and situation.

[bluebackbil]

I have a 20ft TJ OB with the offshore transom and a 90 4stk merc. I bought a ss prop at an outfit called Powertech props. They are very good in helping you select the right prop for your boat and their props are well built. I know the company is based in louisiana, so I don't know if katrina had any effect on them. you can contact them at ptprop.com