Prop Selection on Aluminum 20’ish prince craft I/O

Corey_lax

Crew Member
I Didn’t want to Hi jack the other porpoising thread so I’ll start my own because this boats a I/O and the other is a outboard that can be moved up a hole or two. My pops has a 20’ or so Princecraft riveted aluminum boat with 4.3l merc and alpha one leg, 21 pitch three blade prop. He uses it 95% of the time on a calm 5 km long lake so speed is not of concern.

The boat takes forever to get on plane regardless of weight in the boat. It will start porpoising at cruise if it isn’t trimmed all the way down while at cruise but the time to get on plane is my main concern. He’s got a birthday coming up so would a 4 blade 19 pitch prop hurt or help it get on plane quicker? Or what kind of prop should I be looking at? Or a whale tail?

trim tabs aren’t really an option because the stern corners are completely full of foam. I’d have to cut out a lot of foam to run lines
 
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Same advice as on the other post.
Turning Point Hustler 4 blade 19" sounds like a good choice. Here is the link that has a button on the top right side to find a dealer near you.
https://turningpointpropellers.com/
 
A "whale tail" is cheaper than a prop so that might be a good place to start. Props are pretty complicated...there's way more to choosing a prop than just selecting the number of blades and the stated pitch. This makes comparing props difficult, especially between different prop manufacturers.

One reason that lots of guys say "get a 4-blade prop" is because they generally have more blade area compared to the average 3-blade. So that's gonna be the reason for the benefit; more blade area helps get the boat moving and possible resist ventilation better too.
 
Where

are you located? I have a 14.75" X 19P 4 blade aluminum hustler you can try. It's new in box and might be just right.
Thanks for the offer. I’m in Port Coquitlam. Are you looking to sell that prop or are you keeping it?

I think I’ll try a whale tail for now and see If it helps
 
Thanks for the offer. I’m in Port Coquitlam. Are you looking to sell that prop or are you keeping it?

I think I’ll try a whale tail for now and see If it helps
Whale tail means drilling holes though. I bought a bunch of props when I got my boat, mainly to get the best cruising efficiency. The 19P is too steep by far for my boat and engine, and is just sitting on a shelf. You can have it for Future Considerations :D
 
do the whale tail and try the 19 p prop
should check out what hes getting rpm wise to get her up on step
my 22' with a 4.3 would get there at mid 3K and i could stay on plane as low as 13 mph turning mid 2K
 
Whale tail means drilling holes though. I bought a bunch of props when I got my boat, mainly to get the best cruising efficiency. The 19P is too steep by far for my boat and engine, and is just sitting on a shelf. You can have it for Future Considerations :D
Thanks for the help. I will likely take you up on that offer.
 
Just thought I would chine in here to tell my prop selection experience. I started with a 4 blade stainless 14 3/8 x 18 pitch on my 228 Seafarer as it came with the used Suzuki DF250 that I bought after buying the bare hull. It was Ok, decent hole shot but I was running 5000 rpm at 30mph. I bought a Suzuki 3 blade 16 x 18.5 pitch prop and huge difference, crazy hole shot and then 4400 rpm and 31 mph. Here are the 2 props
 

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I Didn’t want to Hi jack the other porpoising thread so I’ll start my own because this boats a I/O and the other is a outboard that can be moved up a hole or two. My pops has a 20’ or so Princecraft riveted aluminum boat with 4.3l merc and alpha one leg, 21 pitch three blade prop. He uses it 95% of the time on a calm 5 km long lake so speed is not of concern.

The boat takes forever to get on plane regardless of weight in the boat. It will start porpoising at cruise if it isn’t trimmed all the way down while at cruise but the time to get on plane is my main concern. He’s got a birthday coming up so would a 4 blade 19 pitch prop hurt or help it get on plane quicker? Or what kind of prop should I be looking at? Or a whale tail?

trim tabs aren’t really an option because the stern corners are completely full of foam. I’d have to cut out a lot of foam to run lines

I have the same engine on a 21' Glasply (I think it's about 3500lbs with a couple people). I started with an 18 1/2P stainless prop - the WOT was just about 4k RPM (engine rated for 4400 - 4800) doing 24-26knts I also have a whaletail

Yesterday I put a 17P aluminum on and improved holeshot and a little more WOT RPM. Perhaps worth considering?
 
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