Bad prop causing slow speed? NOW WITH PHOTOS

[Bondo]

Re: Bad prop causing slow speed?

Re: Bad prop causing slow speed?

Ayuh,... Something I don't see mentioned....

Have ya changed the trim angles,..??
Is the motor causin' the hull to plow, or porpoise,..??

 

[Texasmark]

Re: Bad prop causing slow speed?

Re: Bad prop causing slow speed?

Took a few photos of the prop. I don't believe it is cupped.

View attachment 135720View attachment 135721View attachment 135722View attachment 135723View attachment 135724

Looking at the rear of the blade where it connects to the barrel looks like a ridge there which is indicative of cupping. However, if it is, it's not much.

 

[Moody Blue]

Re: Bad prop causing slow speed?

Re: Bad prop causing slow speed?

Ayuh,... Something I don't see mentioned....

Have ya changed the trim angles,..??
Is the motor causin' the hull to plow, or porpoise,..??

Yep, the power trim is effective in raising or lowering the bow. I can get about 1/3 (guestimate) of the hull out of the water and I don't experience any porpoising at all.

 

[Moody Blue]

Re: Bad prop causing slow speed?

Re: Bad prop causing slow speed?

Looking at the rear of the blade where it connects to the barrel looks like a ridge there which is indicative of cupping. However, if it is, it's not much.

Honestly I'm not at all familiar with prop construction, but to me, the blades have a real flat profile. I'll try to get a picture with a better angle.

 

[Outsider]

Re: Bad prop causing slow speed?

Re: Bad prop causing slow speed?

Looks like I'll just accept that 25-27 mph is the best I can get with what I've got.

Maybe, maybe not. Two questions: has it always had the same performance, and what is the position of the vent plate relative to the water surface when at WOT? Vent plate about an inch above the keel is a starting point that may or may not be optimum. Take a look at the plate when WOT, it should be very slightly above the surface, but still getting splashed. If it's there, try a 19" or 21", you're over-propped at 17". If it not there, put it there and see what your performance numbers are. Oh, there's a reason the maximum recommended is the maximum recommended. I'm sure it will go higher, but you won't know how high until it comes apart ... :facepalm: