Is There Such A Thing As A Propeller Selection Calculator?

[Roccus7]

OK, this is going to sound idiotic, but here goes. I have an extra prop given to me years ago by a friend. I'd like to check IF it's pitch and size is appropriate for my boat, but I really can't get the info, at least in a non-biased way.

Here are the stats:

Engine: 2013 Yamaha 4-Stroke 115 HP, 377 lbs
Displacement Hull: 22'3" long w/7'8" beam
Hull weight: 2550 empty
Total Boat weight: 2550 + 300 lbs fuel + 300 lbs "stuff" ~ 3200 lbs

I know I want a 3 blade prop, probably aluminum (In Maine we use aluminum propellers as "shear pins" for kissing ledges @ high speed) @ 14", but do I go with the 11 or 12" pitch?

Speed is not a concern, I like to cruise no faster than 20 kts to ensure my dental work and kidneys stay intact.

Is a displacement hull, maybe semidisplacement, I have a small keel the entire length of the boat, a factor in prop selection?

Opinions?

 

[Capt13]

Prop selection is usually based on wot rpms.

 

[Capt13]

Looks like your engine falls between 5300 and 6300. Maybe pick a prop that will get you around 6000 with one pob and light on fuel. Trial and error.

 

[Old Mud]

.Here are a couple bud but your Yammi dealer should be able to get you in the ball park. And she's fun to ask. IMO if you take the specs. from your existing prop and see how close they are. That being said do you like the performance of your prop now ? Ideally you want to be running 75% to 80% load at WOT. Then you won't be over working your engine. The way you run it you won't be having to worry about over taxing your engine.

Boat Prop Guide | Deep Blue Yacht Supply

Propeller Fit Guide

 

[Roccus7]

Crap, it's like buying stereo speakers, but it's much easier to go into an electronics shop with some CDs to test them. Playing musical props isn't my idea for a good time.

I've been happy with what I've got, but too lazy to stand in the mud and pull it off to see what it is so I contacted the boat MFG to see what they ship them out with. Got both the aluminum and SS specs. With the 3X price differential, I'll stick with an aluminum spare.

 

[DarthBaiter]

Kinda late. To the disscussion, but Yamaha has aprop selection guide.

Yamaha.net

I got a used Yamaha saltwater series II, a few years ago for half price off of Ebay. Like Capt13 said, it's about the top RPM.

I had a 19M which was topping my RPM at 5200, I got a 17M off of ebay and it topped out @ 5500-5600 which was what was recommended for my motor.

Now that the old 250hp is gone and I put on a 300hp, I'm glad I didn't get rid of the 19M. So if the 17M gets too much RPM, I can try the old 19M.

 

[DarthBaiter]

I just pelled the 19M out of storage and dang it looka ratty.
Gonna have to drive up to Precision Propeller Repair, just above the West Point, for repair and balancing.