Yamaha T50 on 16 foot boat new prop

[bigbue1212]

I have a 2003 Yamaha T50 four stroke on a Legend (Smoker-Craft) 16 foot aluminum boat with full windshield, trolling motor an two batteries.. It has the original prop on it which is a little worse for wear.

The prop is a Yamaha 13.5x15-K Aluminum prop. My RPMs are around 5400 at full throttle and I get around 33mph out of it.

I was looking at Turning Point props. Particularly the Hustler.

There are two sizes and I'm not sure which one, as they do not have an exact match.

Option A: 13.75x15 model 21431511
Option B: 14x13 model 21431311

Sometimes I have four guys in the boat to do some fishing and the boat has a hard time getting on plane (sometimes it just doesn't). I tried a fin on the back but didn't help much.

Thoughts?

 

[Sea Rider]

That OB revs at wot around 6 K, right ? If so, going for 1-2 less pitch with a OM alum prop should pull your wot revs around there. It's impossible to assume, believe, ask on the forum if those 2 mentioned props will perform right, need to test both on water runs and stay with the one that revs around max wot revs as usually loaded. Ob will not rev same boating with one up than with 4...

Happy Boating

 

[bigbue1212]

I haven't purchased the prop yet. I'm assuming for option B the 2" pitch drop will cause the RPM to rise about 200RPM BUT the 1/2 inch diameter increase will drop the RPM by 100 therefore in theory if I was getting 5400RPM at wot on the old prop, i should get 5500RPM on the new prop....all things being equal.

 

[Vanillaicecream]

I have a similar engine in size and boat. I have three propellers in different pitches. One for low altitude (17p), medium altitude prop (15p) and a high altitude prop (13p).
The 17p prop is smaller diameter than the other two, but it doesn't matter as much as pitch.

I've played around switching them out and testing top speed and hole shot.

From what your saying you need to go down in pitch. Your sounding like your overproped taking so long to come on plane.
When my boat is set up proper with its prop for the altitude, it almost jumps out of the water when loaded and gives great top end.

Erik

 

[Texasmark]

The Turning Point is probably/usually cupped (mine is and they're advertised to be) which is classified as an additional inch of pitch for rpm calculations. So IF everything else were constant, and you were where you belong with rpms and performance with your current prop, you'd need to drop an inch of pitch just to offset the cup of the Hustler from your current prop which I am assuming isn't cupped since it's the OEM original aluminum. Course the Hustler has other things to consider like bow lifting rake, and may be ported which would give you a faster hole shot, better cast aluminum and as a result stiffer blades.

 

[steelespike]

I would go with the 14 X 13.Disregaerd the diameter.You need the 13 especially considering the load and elevation.
If you look up various prop pitches you may note that as pitch goes up diameter goes down.

 

[Texasmark]

I would go with the 14 X 13.Disregaerd the diameter.You need the 13 especially considering the load and elevation.
If you look up various prop pitches you may note that as pitch goes up diameter goes down.

I think that, unless they are changing a characteristic like rake as an example, they are keeping the same blade area just twisting it more which causes the diameter to reduce as you said....course that's pure speculation as I never had the reasoning explained.

 

[Vanillaicecream]

On small motors like our 50hp, just look at pitch for setting up. The diameter doesn't matter much.