What's the right prop?

[MokiCruiser]

Recently I posted a question about the merits of a kicker and got great advice. Now I have gone and purchased a used kicker and could use a bit of advice as to the right prop to use. I bought a 97 Evinrude longshaft 15 HP 2 stroke. The prop is a little bent and so rather than getting it fixed I thought it would be better to get the right prop for my use. It will be going onto my 1976 Sea Ray deep V cuddy. Weight will be somewhere around 3800 lbs. I bought this for a back up security blanket out on the ocean. I might be using it for trolling but that is the secondary use ..... first and foremost I bought it to hopefully get me to safety in an emergency. My main motor is a 302 that will get my boat to slightly over 40 mph. Which of course means that I can get myself quite aways from shore in short order ..... what I am concerned with is getting back when that 302 wont go.

So those are the particulars of what I have, here is the question. Since I am looking for the most "push" for the money, so to speak ..... and I know nothing about props mind you, in plain English what kind of prop would give me the most amount of help getting that 3800 pounds of fiberglass back home.

Thanks again in advance.

 

[mpsyamaha]

Re: What's the right prop?

well you obviously want the engine to operate within its recommended wot range. if you get a baseline with the prop you have now it would help to get an idea of what is ideal.... if the prop is only slightly bent.

 

[elkhunter338]

Re: What's the right prop?

I have some very helpfull advise. My old kicker was a 2001 15hp 2stroke johnson, same as evinrude. I put a tach on the motor and 4 blade 9.25x9 solas prop.
It was on a 21foot starcraft cuddy cabin boat. Boat + trailer weight is 4,000lbs on the axles, so I estimate boat weight is 3800-4200 with 4 people on board. I run the boat in the pacific ocean and have it there for safety and kicker to keep me off the rocks if my main motor quits.

with the 4 blade 9.25x9pitch the motor runs 4500 rpms wot (500 rpms below spec.) spec. is 5000-6000 rpms. and it would push the boat 5mph in the ocean (gps speed).
I also run the motor on a 14ft. Klamath and at 4000 feet elevation and 2 people it runs 5500rpms. So the prop is great for my use.
Solas makes a 10x7 4blade for the 15hp motor which would probaly get the motor in 5,000 rpm range.
I bought my prop at cabelas for less than $100.

 

[MokiCruiser]

Re: What's the right prop?

Thank you for the input ..... and Elkhunter 338, your application sounds very much like my intent. I live in Oregon and will do most of my ocean excursions also in the Pacific out of Winchester Bay, Florence and Newport Oregon. I will look into those props you mentioned.

 

[MokiCruiser]

Re: What's the right prop?

Boy am I dumb ...... I was just reading another prop question and I see that some props have the ears just a bit bent back to make them weedless. In my initial question I said that my prop on the motor I bought was bent a bit. Looking at it now I see that it was an intentional bend on the tips ..... what I have is a weedless prop I think. Since I am looking for the most bang (push) for the buck as a kicker on my 3800 lb boat I really need to change this I think.

 

[elkhunter338]

Re: What's the right prop?

sounds good I would go with the 10x7 4 blade solas or the 10x5 4 blade.
like I said I use the 10x7 4 blade and get 4500 rpms. So the 10x5 should get you 5000ish rpm if you choose. I think speed will not change much. I fish out of newport several times each summer. The 15hp will keep you out of trouble, but crossing the bar on a 15 is not recommended. I did on day, but I had the coast guard follow me just incase.
The coast guard will drag you in accross the bar if needed.
Good luck.