What pitch should I throw now!

[Nick Nameless]

So not being a mechanical genious, I have to be very laymanish here. <br /><br />It seems I need a new prop. Cracked the core hub on mine due to electrolysis. (Damn atnoid) Anyway, I'm not sure of my current pitch. It's a stock prop off a 1980 50hp Merc long shaft. <br /><br />I was curious if I should change to a differant pitch when I replace.<br /><br />I usually only run my 50 to and from my fishing holes which can be up to a 35 mile run. I have a 15.5 ft Hourston Glasscraft and I usually have a max of 2 people. I can cruise at about 27 mph at 5000 rpm and get up on plane around 4200. Engine maxes at 5700. It seems speeds don't range much between 5000 and 5700 maybe 2 mph. I also have dol fin stabilizzer fins on. I can run flat or small water pretty much at full (manual) trim.<br /><br />What I was wondering is if I can adjust pitch to run either faster or cruise at a lower rpm. Basically I want to get fishing asap and burn as little fuel as I can.<br /><br />Any suggestions or should I stay with what I have?

 

[WillyBWright]

Re: What pitch should I throw now!

You could go with a prop 1 inch higher in pitch. You'll get slightly more speed, but your hole shot will suffer a bit. But just one inch...you'll hardly notice either. Check your sacrificial anodes, too. They should corrode away before the prop suffers that much damage. Their surfaces need to be clean, especially where they attach.

 

[Nick Nameless]

Re: What pitch should I throw now!

Thanks WillyBWright, I'm thinking 14p right now. I just can't find out the RPM@WOT recommendations for my engine. No dealers in town here seem to know on the older engines. I've been told anything between 5000-6000 by differant guys. That seems like a bit of a spread to me and I really don't want to buy the wrong prop. I'm not sure the 13 was original or not, or even the right prop for the rig. But I'm sure it was close.<br />14 sounds right but it would ease my mind to be able to do the math first. Also I was able to borrow a 16p prop for the day. I had a pretty losey hole shot and top end speed was close to the same but at 5000rpm instead of 5700rpm.