15x17p vs 16x16p Aluminum 3-Blade for 24' Cruiser?

[syuhas85]

Hello,
My Boat is a 1993 Four Winns 245 Vista with OMC 351 King Cobra (ConeDrive) set up... The prop looks to almost be wooped chewed and tired also with 2 people it runs excellent but with 4 or more she starts to get doggish and not wanting to get on plane.... I seen on Iboats there prop site they have a 16x16P aluminum prop, would this be a good prop to go to or bad???.......

like I said 15x17 now runs great now with 1 to 2 people but there is usually always 4-6 people on board....

as of right now with a Aluminum 15x17P
Cruise is 29/30mph @ 3600rpm
WOT is 36/38 @ 4200rpm


Also yesterday I had 6 people on board and 1 dog, half a tank of fuel (32 gallons) and took forever to get her on plane but once I did and got it trimmed she was porpoising the hole ride back in bouncing up and down on flat water??? is this just because of the weight?? could it be everyone was in the back of the boat??? tryed to play with the trim tabs tryed the outdrive trim I couldnt get rid of the porpoising I ended up pulling the throttle back to make her stop.....

 

[steelespike]

I think it is a very good indication that it planed with 6 plus people apparently without much thought to weight placement.
Porpoising can happen from too much weight in the stern.I think a 16" 4 blade prop should help holeshot.
The 4 blade may also help it stay on plane at reduced throttle, seem smoother and respond better around the dock.
Wot rpm should be about the same you may lose a little top end.

 

[Bifflefan]

Before you go changing pitch, you need a baseline with a prop in good shape. Take yours to your local prop shop and have them fix it. If you dont have a prop shop I would suggest getting a new one that is the same as the old one. 15x17p is about the most popular one there is and is great on for all round use on most boats.
The porpoising is the prop loosing grip on the water, more than the weight.
Imagine your car with 4 flat/bald tires and it is snowing. You would not say the alignment is off when it would not drive straight.
Until you have a prop in good shape to see what is really happening you can not make any accurate decisions.

 

[syuhas85]

I have a spare 15x17p in the boat I'll put that on and give it a try. I was thinking of the 16x16 3 blade or 16p 4 blade just because of all the weight seems when u dock next to family everyone likes to boat hop into ur boat.

 

[jestor68]

The 16 X 16 will provide better acceleration/thrust out of the hole, while running a little less top speed due to the greater blade area of the prop.

So if better thrust to get up on plane is needed, the "bigger" prop is in order.

 

[syuhas85]

The 16 X 16 will provide better acceleration/thrust out of the hole, while running a little less top speed due to the greater blade area of the prop. So if better thrust to get up on plane is needed, the "bigger" prop is in order.

Thanks for info jestor in a opinion would it be better to go for a 16x16 3 blade or 16p 4 blade either way I'm guessing I'm gonna lose top speed don't know how much if I goto 4 blade

 

[Starcraft5834]

15x16 Michigan Wheel 4 blade is the ticket

 

[Starcraft5834]

Losing a mile per hour going to 4 blades a small price to pay for better all around performance..especially with a heavy boat..

 

[jestor68]

I have tested larger diameter 3 blade versus smaller diameter 4 blade on my 23 ft deck boat, and I found the big 3 blade produces more static thrust; that is the thrust produced at initial application of throttle. That's what pushes the boat up onto plane and pulls up the skier.

The smaller diameter 4 blade let the motor rpm rise a little faster initially, and sounded like it was doing something, but that turned out to be just more noise.

The stop watch said the big 3 blade accelerated to 20 mph almost a second faster. That doesn't sound like much, but you could feel the difference.

The 4 blade is back in the box.

​Since every boat is different, the only sure way to see is a direct comparison on your boat

When I first tried to post this, it said I didn't "have permission" ; whatever that means. :facepalm:

 

[jestor68]

When I was looking for a prop for better water ski performance with our 23 ft deck boat, I did a direct comparison between a lager diameter 3 blade versus a smaller diameter 4 blade.

The difference in diameter was 1 inch. The props were both Solas aluminum.

I was looking for basically the same thing you require; more initial thrust, in my case to pull up the slalom skier without dragging him.

The big 3 blade won. The 4 blade sits in the box, on spare duty.

 

[syuhas85]

Thanks for all the input!! I just swapped out my prop with my spare 15x17p at the dock when i flipped it over the props rubber bushing spun it was all twisted the newer spare made a big difference but yet I'd still like to get more thrust we went out last night to watch cedarpoints fireworks... I had 6 people and half a tank of fuel again and still wants to dog with 6 people it planes fairly easy now but I think Im gona go with the 16x16P 3-blade to get that little more Thrust your talking about. I can take the heat on a little speed.. I acutally gained speed with the spare prop last night GPS'd on my way to cedarpoint once I planed out picked up the noise and outdrive trim her WOT was 39mph and cruise was 31mph so im not to worried at loosing a little for more thrust! I'm gonna order the new 3 blade here soon Ill keep up to date and let ya know how much I lost in speed but how it does on pulling her self up on the water...

 

[dazk14]

You didn't mention your new WOT rpm numbers with a functioning prop.

For a go (fairly) fast cruiser I would suggest a 4 blade 15" x 16" pitch. You'll improve the hole shot/planning and it will be a stern lifter, so you'll be on plane at a lower speed which will additionally improve acceleration.

It'll handle better in the rough and around the dock with a slight fuel consumption improvement at cruising.

I think the 16" diameter will drop wot rpm and you'll lose more top speed. If you had a cruiser with a top end in the low 30's, then I'd vote for the larger diameter, but only if you had room to lose a couple hundred rpm.