What pitch? (I know... its a loaded question)

[my05hammer]

Re: What pitch? (I know... its a loaded question)

Cool!! The prop is scheduled for early arrival and will be here today.

 

[my05hammer]

Re: What pitch? (I know... its a loaded question)

Well I got the prop today and in a few minutes I will be going out to install it.

I think I know why the boat would only go 36 mph before I busted up the prop... When I set the new 13X17 prop next to the old 13X19 prop you can clearly see that the old 13X19 must have been repaired or intentionally made smaller (and I didn't think about this at first) but I measured the the old prop and its only 11 inches in dia. It is stamped 13X19 so at one time it was 13.3 in dia (I believe), and someone drilled 3/16th holes at the leading edge of each blade into the hub to relieve the exhaust and cavitate the prop for better low end at low speeds? I don't know for sure but the new prop doesn't have them

I am just going to slap the new 13X17 on there and run it as is.

Going to try it out early tomorrow morning. I will post results in the evening.

 

[my05hammer]

Re: What pitch? (I know... its a loaded question)

I got 39 mph according to GPS with the new 13X17 prop. I just ordered a 13X19. I figure that the boat will hit around 43 mph with the 13X19 prop.

 

[SparkieBoat]

Re: What pitch? (I know... its a loaded question)

what was your RPMs at WOT??? without that info you are really just guessing.

 

[my05hammer]

Re: What pitch? (I know... its a loaded question)

Yup. I have no idea what the rpm was, the sun was too bright for the strobe tach method to work. The motor was screaming though and I went through 3 gal gas in 30 minutes of near full to full throttle boating. There is nothing wrong with the motor so I have to believe that the excessive fuel consumption is related to the prop choice. When I get the 13X19 prop I am going to take it out again and just before dusk we will shoot it with the strobe. I am going to add a tach but not until I refinish/rewire the boat this winter.

 

[SparkieBoat]

Re: What pitch? (I know... its a loaded question)

trying to prop a boat and then adding a RPM gauge is just a little backwards...those props are pricey, and you want to get the right one.