Prop for new motor

[Husker100]

I am getting a new motor for my boat and have been reading and trying to figure out where to start.
I have no idea from the other motor so have figured out weight for starters.
Hull and motor weighs 1400#
people and gear 750# maybe up to 900 on fishing trips to Canada etal.

This is a 08 mercury 115 4 stroke.I have plugged in the numbers for the prop selector at Merc and it comes up with a 13.125x16 vengeance in every category but mid speed cruising then it comes up with 13.125x17. I am not as interested with top speed as I am hole shot with the load and realize I need to get close to top of RPM range at WOT.
Do you think this would be a good place to start? I was also told that the part number for 17 pitch is no longer available.What if I need a 17? Are they not made anymore? Is there an aftermarket prop that is the same as the Vengeance?
I have been thinking of this for a couple months now.The place I am buying motor will work with me to find right prop so I can return it if it is not correct.Thanks for your help everyone..S

 

[HighTrim]

Re: Prop for new motor

The goal in prop selection is to determine what propeller style and size will maximize performance for your boat, while allowing your engine to operate in the recommended RPM range. The correct propeller will prevent the engine from over-revving, yet allow it to reach the minimum RPM where maximum horsepower is produced.

I would get the 16, test run with a light load and ensure you are at the top end of the WOT RPM range.

If your test results in your being able to over-rev the engine, you need to increase the pitch of the propeller. Increasing the pitch increment by 1" will result in approximately a 200 RPM drop.

It is imperative, however, that the wide open throttle RPM fall within the range specified by your engine manufacturer

 

[walleyehed]

Re: Prop for new motor

What altitude are you operating this rig at?
Husker100, are you located in NE.?

 

[Husker100]

Re: Prop for new motor

Yes, In Nebraska. Fish Kansas a lot and Canada too.

 

[walleyehed]

Re: Prop for new motor

OK, if you're at or below 1000ft the Merc prop selector is "close", but if you're like me and live in the western half or close to that, of the state, you'll need to drop atleast 1" and maybe 2 from what the prop selector recommends. I'm in the NW corner of KS and 2-3" drop is required for proper rpm.
If you feel you must stay with a Merc prop, that's your choice, but there are others that may be better suited to your application for half the price with the same or better quality.
You might list what boat you have as well.

 

[Husker100]

Re: Prop for new motor

I live in Southeast Nebraska so should be ok there.I have no problem with an aftermarket prop.Just don't know which one to use for this application.

This boat is a Tracker 17 magna. Aluminum single console.

 

[Husker100]

Re: Prop for new motor

Thanks for your replies Guys!
I am going to go with the Vengeance 16 to start out with.
If I do need to go to a 17 what after market prop would be relative to the vengeance or would I have to start over? I do not know why they dont make a 17 pitch Vengeance anymore.At least thats what I was told..Thanks again..S.

 

[walleyehed]

Re: Prop for new motor

The Vengeance is Mercs Step-up prop from aluminum.
Do as you wish, but if I were to prop it to run away from the Vengeance and have the same handling and Trolling speed and the same wot rpm, I'd go with a Stiletto on that style of boat......and half the price of the Merc Prop.

 

[Husker100]

Re: Prop for new motor

Thanks walleye.Like I said I have no other knowledge of prop brand to use other than the merc propfinder.
I have looked and can't find a 16 stiletto.I did find these on the internet.Problem is if this is the wrong prop if I can exchange or not.Do any of these aftermarket prop sites have a prop finder tool?

 

[walleyehed]

Re: Prop for new motor

Most aftermarket companies offer some sort of selection "Guide"...Precision's approach is to use the people that sell or deal with there props on a regular basis.
Some of the test data that I once had posted, listed about 40 props in this class...a change of boards and time, has displaced most of the prop testing threads I had.
I can tell you this much...the Stiletto is a great match for the size and style of boat you have.
The problem with the 16P is pitch varies as stamped from 1 brand to another...technology differs from 1 brand to another.
And, believe it or not, I have some stock props, for example, that don't just turn slower with more pitch, or just turn faster with less. I have a few (stock) SS props in a given pitch, that will run the same RPM, yet run a faster speed than some ss props in the next pitch size UP!
The technology usually results in higher fuel efficiency and these props are available OTC.
I wouldn't tell you not to buy the Vengeance..but if you do, I would like to see the numbers you get with the 16 and we can figure slip from there.
Yes, I've ran the Vengeance in several tests...none of which were 16P so I can't give you an exact # on how it will compare on your rig.
Years back as I was trying to learn as much as I could about what prop does what and why, a gent on this forum by the name of Dhadley suggested I try a certain prop....I thought.."How could that do so much better than what I have that it makes it worth trying?"
I found and ran the prop he suggested a few weeks later....I have never looked back..I dove in head-first into prop testing and learned from him AND the props as I went. It got so bad, I ran 2 summers just testing props-fished very little...it sticks in your blood...hard.
I would recommend you buy the prop you feel most comfortable with at this point. When you are ready to tweak the engine heigth here, maybe add some set-back there, we can add a bunch of performance for a couple of hours spent.
You may be plum happy with the Vengeance and not want to go any farther....it's an install and test thing....
Good luck!