# Hells Bay Waterman, Yamaha 70hp 2 Stroke



## reallyshallow (May 19, 2010)

Which prop would you recommended with an Atlas 4" jack-plate?


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## TC (Feb 15, 2011)

I have an '07 Gordon Waterman 18 with a 2 stroke 70 Yamaha and I'm currently running a PowerTech RED3R14PYM90. I also have this prop in a 13P. I've run both but get a little better top speed with the 14. Hole shot is great with both. Jeff at PowerTech confirmed these were the best props for my set up. 

Having said that, I do not have a JP, so I'm not sure if my response is of any help.


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## reallyshallow (May 19, 2010)

I'm now running a Powertech SCD4 17 pitch. So far the best I've seen is 38.1 at 5800rpm's, but that was with 3 people with a full load and a 21 gals of fuel.

What kind of numbers are you getting?


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## TC (Feb 15, 2011)

You're getting better top speed than me. The best I've seen with the 14P is 35 mph @ about 5700 rpm and that's with a light load. How's your hole shot with that 17?


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## reallyshallow (May 19, 2010)

It's very good, the prop comes alive once I have the jackplate at 3"-4".  I'm considering getting a SCD3 18-19 and see how shes performs.


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## reallyshallow (May 19, 2010)

I was surprised how well the 70, 2 stroke turns this big prop.


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## MariettaMike (Jun 14, 2012)

> I'm now running a Powertech SCD4 17 pitch.  So far the best I've seen is 38.1 at 5800rpm's, but that was with 3 people with a full load and a 21 gals of fuel.
> 
> What kind of numbers are you getting?


You're either trimming up to aerate that prop or cavitating badly because you're slipping 8 mph from theoretical speed of 46.1. 

You may find you will get better hole shot and overall fuel economy with a lower pitch prop that isn't slipping.


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## reallyshallow (May 19, 2010)

> > I'm now running a Powertech SCD4 17 pitch.  So far the best I've seen is 38.1 at 5800rpm's, but that was with 3 people with a full load and a 21 gals of fuel.
> >
> > What kind of numbers are you getting?
> 
> ...


Jacked up to 4" and half trimmed. The prop is vented (so that helps on hole shot) and does not cavitate at all.  Theoretical speed at 5% slip (which is where I'm at) is 40mph.


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## TC (Feb 15, 2011)

Can either of you tell me what speed I should be seeing from my 14P at 5700 rpm?


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## reallyshallow (May 19, 2010)

> Can either of you tell me what speed I should be seeing from my 14P at 5700 rpm?


According to the calculator 32mph


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## TC (Feb 15, 2011)

> > Can either of you tell me what speed I should be seeing from my 14P at 5700 rpm?
> 
> 
> According to the calculator 32mph


Cool. I'm doing okay, then, I suppose.


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