Need prop help for Waterskiing or hydrofoil????

[sturgeonx]

~~I have a 2010 Larsen Senzav 206 with a 5.0 MPI, alpha 1.

The current prop came with boat which is an aluminum mercury prop in 19 pitch. I can't read the diameter. I would like to have a prop so I can plane a lower speeds when towing the kids for water skiing. At WOT it runs at 52- 55 mph GPS at 5000 RPM's. I can only stay on plane at 20-22 mph and would like to be around 15-18 if possible. Hole shot is good and I am not worried about losing top end. I was looking at the Alpha 4. Would this work in 18 pitch and how much is one with the hub kit? Do you have any other suggestions aluminum or stainless.

An high five was also suggested but the cost is too much unless I can find a used one.

Somebody else recommended using a Hydrofoil and was looking at the SE Sport 400.

thanks

Sturgoenx

 

[tpenfield]

4 blade 17P stainless . . . might need to be careful not to over rev on the high end.

I think the hydrofoil won't do much. . . more of a small outboard thing IMO.

 

[floater212]

you can go to dan's discount props and use the prop wizard, that will get you some great info... I think mercrury has a prop wizard too.

 

[Chris1956]

Adjustable trim tabs (Bennett, Lenco) would allow you to plane at lower speed. Pick up some oversized ones. You don't want to ruin your top speed by underpropping.

 

[steelespike]

See if there is a Mercury Spitfire for your setup.I've a seen independent tests indicating close to amazing performance.
These 4 blades don't sacrifice top end and usually swap out in the same pitch.

 

[sturgeonx]

Would the spitfire be better than the alpha4? Merc site suggests high five or vensura for watersports for stainless. I dont have the 500$ for the stainless.

 

[KYsean]

Would the spitfire be better than the alpha4? Merc site suggests high five or vensura for watersports for stainless. I dont have the 500$ for the stainless.

Actually it would be better because you won't lose any top end. I had the alpha 4 and like the spitfire much better. I also have the 5.0 alpha 1 on a 21.5 boat. The spitfire gets you on plane FAST and is great for water sports. Spitfire comes with a hub kit.

 

[Starcraft5834]

"At WOT it runs at 52- 55 mph GPS at 5000 RPM's"


answer= 4 blade.. at 19p. you need to bring down your rpm's too. 4 blade is the answer

 

[sturgeonx]

Will the spirfire allow to stay on plane at lower speeds? Or should i look for a used 19 P high five?

 

[Starcraft5834]

if both of those are 4 blades in same pitch, performance differences minor... I'd be more concerned getting my engine into recommended RPM range at the top end.. 5K is a bit to high.. if you are speaking of 4 blade in the manf you stated, either should improve your ability to maintain plane at slower speeds. the 4 blades provide a substanial boost in sustained thrust, (there's an extra blade there shoving you along)..if your boat is on the heavy side, 4 blades are recommended

 

[walleyehed]

Blade number will not change the speed "much" at which the boat planes out and stays there...it will however change how quick it gets you from zero to on-plane.
Nauticus Tabs are the best bang for the buck and will allow boat to stay on plane approx. 3-4mph slower and they are self actuating. nothing to screw with when trying to drive the boat.

 

[jestor68]

I use the Doel Fin hydrofoil on my 23 ft deck boat/Mercruiser. It allows the boat to plane at very slow speeds ( much slower than without), and keeps the speed right there, nice and steady.

If you're turning 5K rpm, you have the correct prop for water sports.

Beat bang for the buck; how about $38 versus $ 100+ and a bunch of holes in your transom.

 

[walleyehed]

I agree with Jestor68 on the rpm....don't prop any lower than that.

 

[sturgeonx]

The WOT RPM range on the engine is 4600-5000. A prop shop suggested the Powertech ELE4 in 17 pitch. Said I would plan an lower speed and get more lift with this prop. They said for the price this prop is a very good prop.

Anybody else use this prop or disagree with this suggestion.

thanks

 

[jestor68]

The WOT RPM range on the engine is 4600-5000. A prop shop suggested the Powertech ELE4 in 17 pitch. Said I would plan an lower speed and get more lift with this prop. They said for the price this prop is a very good prop.

Anybody else use this prop or disagree with this suggestion.

thanks

The prop shop is trying to sell you a prop that you don't need. There is not one thing wrong with your prop.

You need a planing aid. Whether it be a hydrofoil or smart tabs is your choice. You do not need a different prop.

 

[Fastatv]

I agree with a couple of the guys here. One, if your WOT rpm is 5000 and that is what's recommended for your engine set up, you are propped correctly. Now, many will disagree on the Doel Fin, however, I agree there as well. Jestor gave you his example on the fin, I have one as well ( actually more than one ). I had a 1985 Winner Escape Cuddy Cabin, a 19 footer. My boat would not stay on plane slow enough for us to kneeboard. I installed a Doel Fin, and the boat would stay on plane probably 5 or 6 miles per hour slower. It was an inexpensive, very good working solution for what I was trying to accomplish.

 

[sturgeonx]

I will look into buying the SE Sport 400 cause I won't have to drill hole in the plate.

thanks

sturgeonx