Heavy load/altitude prop

I currently run two different props but both are 14.5 x 19p.aluminum. The main one we use has tons of bow lift, it works great for wakeboarding when its just our family of four, feels like it digs a giant hole in the water and puts out a decent wake. But I am constantly making trim and throttle adjustments to keep it on plane at lower speeds. Also feels like it rides low in the water and the boat seems to pound in chop.

The second 19p. I have is totally different, it has tons of stern lift. Again under light load this prop works great I feel like it makes the boat ride better in chop and I dont have to keep adjusting the throttle to keep it on plane at lower speeds.

I really like how the #2 prop feels, the problem is under heavy loads it really struggles to plane out. The #1 prop has no problem getting going under heavy loads but I feel like the boat rides rougher through chop.

So I would like to find a prop that acts like #2 but can perform that way under heavy load or at altitude. Hopefully through my rambling some one can make sense of what I'm feeling and point me in the right direction.

1997 Wellcraft eclipse 2000 ss. 5.7 VP.sx 1.60, 220 hp.
mostly used for tubing, wakeboarding and cruising.
Length 20.5, semi "V", clean bottom
8' beam
3300 lbs. dry
Normal load 700 lbs.
Prop #1 48mph @4800 Prop #2 48/9mph @4800
Heavy load 1600lbs
Sorry no wot #s but prop #1 can cruise 30mph @3500

Re: Heavy load/altitude prop

Seems odd that a prop that appears to offer stern lift has trouble planing a load.
Could it be #2 is just a really generic prop offering little and appears to offer stern lift simply because there is no bow lift?Shooting from the hip I would suggest a 4 bld
18" prop.This should get a load up and stay on plane with less power and fiddling.
May have a slightly lower top end.

Re: Heavy load/altitude prop

A high five digs like a gopher, but is ventilated so the hole shot is like a neutral drop. If you can, try one in 18" or 19".

John

Re: Heavy load/altitude prop

Ripper, Spike is right as always, I show your motor should ONLY turn 4,600 RPM at WOT with a 1,51:1 gear ratio, please verify this. I also need to know if 4,800 is your maximum RPM with these props, you did not make that very clear.

If that is correct then you need to buy a Solas Amita 19" pitch aluminum 4 blade prop to get the RPM right. You will be able to plane at much slower RPM and speed, as well as your acceleration will increase a lot, and you should not lose any speed, because you are showing a 16% prop slip right now with an effective prop pitch of 15.9" and the Solas will lower the prop slip and gain effective pitch. You can buy that prop right here at Iboats for right at $ 100.

You might try reading this for a better understanding of changing props for better performance, and for the major differences between aluminum props and stainless steel.

http://forums.iboats.com/showthread.php?t=369057

I forgot to ask how much difference in altitude will you be changing to, that is very Important.

H

Re: Heavy load/altitude prop

Ok guys thanks for responding. So just to be clear my drive is an sx. with a 1.60:1 ratio. Both props can run up to 4800@ wot. H, I was not aware that my engine should run 4600@wot, always thought 4800 was the upper limit for some reason? We go to a lake here in Cali thats about 4500ft above sea level


Spike, I get what your saying about having no bow lift with the #2, it made me think about what position I run the drive in when taking off. When underway with prop #1 I can run with the drive all the way down and it will never ever plow, prop #2 plows big time unless I run the drive way up. So maybe I'm just taking off with the drive to low and the #2 prop is just pushing the bow down so far its plowing when trying to come up on plane??? Does that even make sense? Let me know what you guys think. Thanks.

Re: Heavy load/altitude prop

Ripper,

Ok guys thanks for responding. So just to be clear my drive is an sx. with a 1.60:1 ratio. Both props can run up to 4800@ wot. H, I was not aware that my engine should run 4600@wot, always thought 4800 was the upper limit for some reason? We go to a lake here in Cali thats about 4500ft above sea level

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With a 1.60:1 gear ratio I show your prop slip is only 11% and your effective pith is 16.9, which is good.

I could be wrong about your RPM, but that is what my information shows, because I was wrong about the gear ratio. But you will only lose about 250 RPM going to the Solas anyway.

IF the 2 props you are using now develop the 4,800 RPM at that 4,500' elevation, then the 19" Solas 4 blade will work perfectly for the heavy loads.

So maybe I'm just taking off with the drive to low and the #2 prop is just pushing the bow down so far its plowing when trying to come up on plane??? Does that even make sense? Let me know what you guys think. Thanks.

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Yes it does and you just trim it up some to get on plane, because it is pushing the stern up which makes the bow go down some.


H