3 blade 19P to 4 blade 17P... thoughts?

[jkimball]

'99 FW Horizon 170, 115HP Johnson V4
14x19" Aluminum (Factory OMC)
5000-5100 RPMs @ 39-41 MPH WOT with normal load
Stingray Starfire Hydrofoil
Prop Blows out in semi-tight turns,
Boat falls on its face in turns with a tube behind it.

I want a better riding boat, with good hole shot, good cruise, and I don't want to lose too much top end. Most of the time I don't go WOT for very long anyhow.

5000-5100 seems low considering my WOT suggested is 4500~5500 RPMs

I am highly considering Solas Amita 4 blade, 12.75x17P. I realize that going down in pitch should increase my RPMs, but not the same as going down in pitch with a 3 blade as the larger surface area will decrease this.

Is there any reason I should not consider a 4 blade?

Mainly use the boat for crusing, tubing, and occassionally have max capacity of 6-7 adults/ teens.
It seems a 4 blade will, especially lower pitch will give more efficiency & "power" in the range I use it.

 

[jestor68]

Re: 3 blade 19P to 4 blade 17P... thoughts?

Since you would normally drop an inch of pitch just to maintain the rpm when switching from 3 to 4 blades, the 17 pitch would be the logical choice to raise the rpm 150-200 rpm.

The 4 blade will produce better acceleration and holding in turns.

 

[tahoejag]

Re: 3 blade 19P to 4 blade 17P... thoughts?

5000-5100 seems low considering my WOT suggested is 4500~5500 RPMs

I am highly considering Solas Amita 4 blade, 12.75x17P.

I noticed the change in diameter as well being over an inch...which comes in mind that would also be like going down another inch in pitch??? May put you rite around the max recommended rpm range. JMO.

Is there any reason I should not consider a 4 blade?

Mainly use the boat for crusing, tubing, and occassionally have max capacity of 6-7 adults/ teens.
It seems a 4 blade will, especially lower pitch will give more efficiency & "power" in the range I use it.

I went to a 4 blade alum 14x20 from a 3 blade alum (factory was 14.25x21). the diff is nite and day!
- better holeshot
- very quick to plane
- lower minimun planing speed (15 mph @ 27/2800 rpm vice the 3 blade 18/19 mph @ 3000 rpm)
- better fuel economy
- holds well in very tight turns! 3 blade blew out....
- The only con that I come up with is minimum loss in top end speed, but hardly noticeable.

Kudos to Jester....imo knows props and gives out great advice! I have learned from reading his posts.

 

[jkimball]

Re: 3 blade 19P to 4 blade 17P... thoughts?

Thanks for the help and advice guys, I ended up buying an OMC Factory 14x17 Stainless 3 blade, I think it's the SST (1) Man, that thing is heavy!
But I figured I would try a stainless, and a 17" prop before spending the extra $$ on a new prop just to chance seeing that the drop in pitch wasn't for me.
I got it for $100 shipped on Ebay, so if all else fails I should be able to sell it again quickly, or for that price at least I have a spare.

 

[eavega]

Re: 3 blade 19P to 4 blade 17P... thoughts?

I got it for $100 shipped on Ebay, so if all else fails I should be able to sell it again quickly, or for that price at least I have a spare.

Be warned, I thought the same thing when I purchased a second SST prop for my Johnson outboard. I have been trying to sell it between e-bay and Craigslist for over a year now. I got it for $120 on e-bay. It was pretty good condition (a small ding on the outside edge close to the hub on one blade), and have been unable to sell it for $100.

Rgds

 

[jkimball]

Re: 3 blade 19P to 4 blade 17P... thoughts?

Be warned, I thought the same thing when I purchased a second SST prop for my Johnson outboard. I have been trying to sell it between e-bay and Craigslist for over a year now. I got it for $120 on e-bay. It was pretty good condition (a small ding on the outside edge close to the hub on one blade), and have been unable to sell it for $100.

Rgds

What was your reason for wanting to sell? Did the SST not perform well? I'm hoping to notice a (desirable) difference from the 19P Aluminum (that is worn & has a bent tip from previous owner)

 

[eavega]

Re: 3 blade 19P to 4 blade 17P... thoughts?

What was your reason for wanting to sell? Did the SST not perform well? I'm hoping to notice a (desirable) difference from the 19P Aluminum (that is worn & has a bent tip from previous owner)

The SST performed reasonably well (not as well as I had hoped, but that is another issue. Lesson learned, there is much more to consider when selecting a prop than pitch and material). I sold the boat shortly after acquiring this prop, and when I sold the boat I put a serviceable aluminum prop on it. I figured I was not going to get any more for the boat if I put the SST on it, and I "thought" I could sell the SST prop for a decent amount.

Rgds

Eric

 

[jkimball]

Re: 3 blade 19P to 4 blade 17P... thoughts?

So I put the new prop on today and got it to the water... just to find out I think I got taken and bought a bad prop. The prop is a 13 3/8 x 17 SST. My original was 14 x 19 Aluminum.
Anyhow, when I got it in the water, I thought all was well. It was a little more responsive in reverse, and seemed to have more "oomph" around the dock, well when I was leaving the dock, in the no wake zone I cruised out at about 2000-2500 RPMs. No problem.
Once I went to leave the no wake zone, I barreled down on it to get out of the hole and on plane, and the RPMs went through the roof, and the boat went nowhere. If I eased into it, I could get the RPMs up to about 4000 before it started spinning again.
Does this mean the hub is spun?

 

[Okieboatguy]

Re: 3 blade 19P to 4 blade 17P... thoughts?

Yes, That is a spun prop.....
To verify, you place a scratch mark on the hub of the prop that makes contact with your shaft and a second one in line with the first on the prop itself. If you then gun it ant it is all gas and no go, raise it and see if the lines have moved away from each other, that will verify if it is spun. I had one last year that did the same, however mine was a new out of box Quick Silver, that was on the shelf for 3 years until I bought it at a "Good" price. It cost me $60 bucks to get it re-hubbed.

 

[jkimball]

Re: 3 blade 19P to 4 blade 17P... thoughts?

Yes, That is a spun prop.....
To verify, you place a scratch mark on the hub of the prop that makes contact with your shaft and a second one in line with the first on the prop itself. If you then gun it ant it is all gas and no go, raise it and see if the lines have moved away from each other, that will verify if it is spun. I had one last year that did the same, however mine was a new out of box Quick Silver, that was on the shelf for 3 years until I bought it at a "Good" price. It cost me $60 bucks to get it re-hubbed.

So, I ended up getting it rehubbed for $46 & the seller refunded me $50 towards the cost. So all in all I feel everything came out ok.
I still haven't put the prop on the boat, it won't be out of the shop until Monday, once I get it I'm going to put it on and go get the boat wet. I hope it all works out.
What do you think I'll experience with going from a worn 14x19 Aluminum with a bent tip to a 13 3/8 x 17 Stainless?
The Stainless is heavy as hell, but the blade edges are really thin, and it has some cupping.
My current performance is 5100 ~ RPM @ 39-41 MPH fully trimmed (with a hydrofoil) Maybe I can lose the foil with the smaller pitch prop?

 

[CaliBoatBoy]

Re: 3 blade 19P to 4 blade 17P... thoughts?

I just put on a 14.5 x 17 pitch Solas Amita on my boat. Wellcraft 4.3 V6 with an Alpha One. My other prop is a SS 19" 3 blade. It was just OK for skiing, wakeboarding, tubing, etc.

Hole shot is unreal now. It's a different boat! Ripped my but (220 lbs) out of the water like I was a child. Plane is less than 3 sec. Lost about 5 mph on top end (big whoop) RPM can easily be exceeded so BE VERY CAREFUL.

LOVE this prop and if this is the low end and they only get better with SS 4 blade, I am geeked!

 

[jkimball]

Re: 3 blade 19P to 4 blade 17P... thoughts?

I just put on a 14.5 x 17 pitch Solas Amita on my boat. Wellcraft 4.3 V6 with an Alpha One. My other prop is a SS 19" 3 blade. It was just OK for skiing, wakeboarding, tubing, etc.

Hole shot is unreal now. It's a different boat! Ripped my but (220 lbs) out of the water like I was a child. Plane is less than 3 sec. Lost about 5 mph on top end (big whoop) RPM can easily be exceeded so BE VERY CAREFUL.

LOVE this prop and if this is the low end and they only get better with SS 4 blade, I am geeked!

So, I finally got the SS 17" prop back from getting a new hub, Man it's like a whole new boat!!!
This thing is ridiculous! The holeshot is unbelievable!!! Mid-range power is awesome, and all of my speeds at all RPMs remained about the same or 1 MPH over. The only difference being that my WOT increased to about 5500 which is the peak of my RPM range and I gained 4-5 MPH top end.

This leads me to think that my old 19" aluminum must have lost a lot of its original pitch and was really sucking hind ***.
This boat feels like a monster out of the hole now!

Also, there's really no vibration to note either.

I'm really curious to try my luck with a 4 blade 17" now that I kind of see where I'm at.