Prop gurus!

[Ctyson9]

I have a 16/56 edge/Waco aluminum duck/fishing boat with a 40hp Etec... I'm running a 13.25x17 BRP SST prop... At WOT I'm running around 5750RPMs WOT and GPS speed of 35 mph.. I just don't feel like this prop performs the way I'd like, it doesn't seem to bite great on corners and also feels like I should be able to trim higher without bouncing therefore im missing out on a little speed...My question is, if I don't need to go up in pitch since my rpms seem fairly good is there a different brand prop that would give me better performance?
Thanks

 

[jestor68]

Re: Prop gurus!

The next step up in a BRP prop would be a Viper 13-7/8 X 17. The viper is a more aggressive design and is considered a "bow lifter", whereas your standard SSP prop is basically the same design as the aluminum prop; just in SS.

The Viper 17" would do a better job of holding the bow up, as well as perform better(less ventilation)in turns.

Due to the more aggressive design, you will probably drop a hundred or so rpm, but as long as you stay at 5500rpm +, you'll be OK; as that's where your motor's HP is rated at.

 

[Ctyson9]

Re: Prop gurus!

Will I lose any speed with the viper? So There aren't any after market props that would do better on top end and turns than a BRP?

Thanks

 

[Ctyson9]

Re: Prop gurus!

Anybody else got a suggestion on prop manufacturer for performance? Turning Point, powertech, etc...

Thanks!

 

[jestor68]

Re: Prop gurus!

Will I lose any speed with the viper? So There aren't any after market props that would do better on top end and turns than a BRP?

Thanks

The Viper should perform better than the SSP; over all, including top speed.

 

[Ctyson9]

Re: Prop gurus!

Awesome!! Just didn't know if that big of a diameter would do better? Well a viper it is then! Thanks for the input jestor!!

 

[Ctyson9]

Re: Prop gurus!

Viper should be here today. I'm gonna try and take the boat out with it on.. I'll let you know the results!

 

[Ctyson9]

Re: Prop gurus!

Well I ran the viper... 33mph WOT,, 6,018 RPMs with it trimmed as high as I could get it without bouncing!! I never dreamed that!! This was by myself with 2 batteries and trolling motor... I'm guessing my SSP 17 pitch would b higher than that, cause I ran it with the same gear I just mentioned but with 2 people and it was running 5650 RPMs,, my dealer where I bought the boat and motor had told me they propped the SSP out and it was running 5700rpms.. I'm guessing they where way off? I didn't have the tachometer when I had run the SSP by myself before so I was just estimating since I ran 5650 with 2 guys I just figured there numbers from the the dealer where pretty close that's why I said 5750rpms in my first post(I'm an idiot!) so now I'm sending the 17 viper back, so I guess I need a 19 now? What's ur thoughts jestor? Oh and the 35mph I mentioned in my first post was done with one battery ,by myself and no trolling motor,,,

 

[jestor68]

Re: Prop gurus!

Well, the 6000 rpm with a light load is spot on , but unexpected.

What about other performance factors, like hole shot, holding in turns, etc? Is straight line speed all you're interested in? A prop that ventilates easily in turns isn't good performance.

What sort of tach? How are measuring speed? If that rpm reading is accurate, a Raker 18 pitch may be in order.

 

[jestor68]

Re: Prop gurus!

When I calculated slip before, I used the wrong(2.06) gear ratio. Using the correct(2.67) gear ratio, matters are different.

According to the slip calculator, you should only be able to go 34 mph with a 17 SSP @ 5650 rpm. You stated speed represents no slip, which is not likely with that hull. Using the same 8% slip, that comes out to 31 mph.

The 17 Viper @ 6000 rpm shows theoretical speed of 36 mph, and 33 mph with a 8% slip. Those numbers sound realistic.

Since this is a kind of step by step process, the next logical step would be the Raker 18 pitch.

Considering the type of boat you have(fairly flat;8 degree dead rise bottom) The Raker may only give you an additional mph or two. But in terms of over all performance, it'll beat the others.

 

[Ctyson9]

Re: Prop gurus!

I'm using a works connection tach, GPS speed, hole shot is still excellent the viper seemed to be smoother and hold turns without ventilating also,,, just the high RPMs is what had me concerned.... I'm not sure of the speed at the 5650rpms with the SSP as I didn't have the GPS that day? Yes I'd like to have the bestof both worlds, straight line speed and good turning performance,,, do you think the viper 19 would work?

 

[Ctyson9]

Re: Prop gurus!

What kind of performance could I expect with a 19 viper or a 18 raker?

 

[Ctyson9]

Re: Prop gurus!

Just seen the end of your last post jestor68,,, just don't want to get a raker 18 and during hunting season when I'm by myself with one battery and no trolling motor to put me over the rev limit? But if you think that's the one I will need and not put me over the rev ill look into it.... Just hate to keep buying these expensive props then try and resale them if they don't work? Which I know that's part of finding the correct prop

 

[Ctyson9]

Re: Prop gurus!

Also this is a light hull... .90 gauge aluminum

 

[jestor68]

Re: Prop gurus!

What kind of performance could I expect with a 19 viper or a 18 raker?

Since your motor is able to turn the Viper well(to 6000 rpm), I'd say it's time to step up to the ultimate BRP prop; which is the Raker. I'm not sure if they make the Raker II for your motor. I believe it's for the larger motors.

It's the most aggressive BRP prop for your motor and will out perform the others. An added benefit of it's aggressive design is the ability to raise the motor higher on the transom to reduce drag and pick up more speed without sacrificing turning performance.

The calculator shows to expect a couple of mph increase if you don't change your set up. But raising the motor a hole(or two) will add a couple more. I have seen 5-6 mph gains by playing with the set up.

If the vender where you got the Viper will swap it out, I'd go all the way and get the Raker.

 

[jestor68]

Re: Prop gurus!

Also this is a light hull... .90 gauge aluminum

It's not that light. Bare hull is 388lbs. With motor it's 637. With a couple people/gear/12 gals gas you're pushing 1300-1400lbs.

 

[Ctyson9]

Re: Prop gurus!

18 pitch on the raker right? I don't have a jack plate to raise the motor, I have a cmc BA130 breakaway plate, also have power trim...

 

[jestor68]

Re: Prop gurus!

18 pitch on the raker right? I don't have a jack plate to raise the motor, I have a cmc BA130 breakaway plate, also have power trim...

I would try the Raker in the current set up first. That's going to give up a boost in performance.

If you decide to play with the motor height, simply unbolt it where ever it's bolted on and raise it one hole and bolt back on. You shouldn't even have to remove the lower bolts; just loosen them and remove the upper bolts to raise it one hole.

 

[Ctyson9]

Re: Prop gurus!

Thanks

 

[JC21]

Re: Prop gurus!

Hey if you don't mind posting how did the raker work for you? I run an etec 50 tiller on a 1648 wareagle fairly similar to your set up. Currently I'm running a 19 pitch solas Rubex aluminum. I too am looking to go stainless. I don't believe to much in those prop calculators for hulls like ours. I'm running 38-39 mph at 56-5700 Rpms which shows a negative slip but ive had my tach checked and its working right and had multiple people test gps speeds it don't matter if its just me or 3 of us and duck hunting gear it plains quickly and tops out the same. I'd just like to know which prop worked best for you so I have an idea where to start.