This boat was purchased virtually new, but the 14x19 3-blade AL prop was slightly dinged - Prop #176215. The boat ran well, 42-44mph indicated with a load of 750lbs.
I wanted a spare prop, and a little more pulling power and smoothness, and didn't care about top speed. We use it mainly for skiing/tubing, and putting around. Very little top speed use.
There doesn't seem a finite formula for this, every boat/motor/use combo is unique.
After too much fingernail knawing I finally settled on a Solas 12.5x19 4-blade aluminum fixed hub.
The pitch on the original seemed about right, and I thought the 4-blade, reduced diameter (12.5" v. 14") would meet the goals I was aiming for. The main differences I noted beside the extrra blade is that the Solas blades are not as deep measuring front to the rear of the prop, but it may be that there is not enough space on a prop with this hub size for deeper blades without overlap. About $100 delivered here on iBoats - seems like a very good price and fast delivery.
These 4-blade props seem aimed at the 4-strokers, so I was a little concerned about putting one on a 2-stroke. But it worked out much as I'd hoped.
The boat pulls harder, and runs smoother. Pulling a 2-person tube with 300lbs on it, and with 500lbs. of people aboard, the boat it planed off fairly quickly and without much fuss, top speed about 36-38mph indicated. Same with 100lbs on the tube and 700lbs in the boat (didn't try wot here).
I'm not sure about top end, I didn't make an apples-apples test. I reached a higher speed indicated, 46-47mph, but with a light load. Faster than I care to go. It also 'putts' about more smoothly.
Sadly the tach isn't working, although the System Check does?? Fixing that is next.
Folks all say diameter doesn't mean much, but I wonder. All else equal, less diameter means moving less water which is all the prop does, and so would have to take less power. Adding the 4th blade may nullify the dameter difference, perhaps those who know more will comment.
Perhaps this will help someone in a similar quandry.
I wanted a spare prop, and a little more pulling power and smoothness, and didn't care about top speed. We use it mainly for skiing/tubing, and putting around. Very little top speed use.
There doesn't seem a finite formula for this, every boat/motor/use combo is unique.
After too much fingernail knawing I finally settled on a Solas 12.5x19 4-blade aluminum fixed hub.
The pitch on the original seemed about right, and I thought the 4-blade, reduced diameter (12.5" v. 14") would meet the goals I was aiming for. The main differences I noted beside the extrra blade is that the Solas blades are not as deep measuring front to the rear of the prop, but it may be that there is not enough space on a prop with this hub size for deeper blades without overlap. About $100 delivered here on iBoats - seems like a very good price and fast delivery.
These 4-blade props seem aimed at the 4-strokers, so I was a little concerned about putting one on a 2-stroke. But it worked out much as I'd hoped.
The boat pulls harder, and runs smoother. Pulling a 2-person tube with 300lbs on it, and with 500lbs. of people aboard, the boat it planed off fairly quickly and without much fuss, top speed about 36-38mph indicated. Same with 100lbs on the tube and 700lbs in the boat (didn't try wot here).
I'm not sure about top end, I didn't make an apples-apples test. I reached a higher speed indicated, 46-47mph, but with a light load. Faster than I care to go. It also 'putts' about more smoothly.
Sadly the tach isn't working, although the System Check does?? Fixing that is next.
Folks all say diameter doesn't mean much, but I wonder. All else equal, less diameter means moving less water which is all the prop does, and so would have to take less power. Adding the 4th blade may nullify the dameter difference, perhaps those who know more will comment.
Perhaps this will help someone in a similar quandry.