Replacement Prop

[Anacletus]

I have a 1986 Cobalt Condurre 223 and I’m looking for a stainless replacement prop. Stamped on the current prop is 992005 which I find to be a Michigan Wheel Vortex. Can I use the same specs, just in stainless? Looking for the best mix of speed, performance and economy; if you can have all three. Thanks.

[Elkhunter2372]

Anacletus, since no one else has chimed in, I'll throw in my $.02...what you have currently is a 21 pitch, right hand spin, aluminum, 3 blade prop. You can certainly go to a stainless steel prop, same specs, same pitch. Or you can play around a little. My previous Monterey was a 19.5 foot bowrider with a 5.7 Merc. I pulled kids on tubes, wakeboards, water skis and just ran up and down the lake. I got a tremendous amount of prop slip when I would hook up to our 4 man tube, especially with 4 adults on it. I played around with different props and finally settled on a 21 pitch High Five....a stainless steel 5 blade prop. I lost some top end, but the hole shot was amazing. One of my local boat dealers would allow you to purchase a prop, take it to the lake and try it, and if you didn't like it then you could bring it back and return it for full credit towards a different prop. Props are somewhat of a "buy what you like" item....so with all of the above being said....you said you are looking for best mix of speed, performance and economy. We probably need some more information from you.

Do you have a lot of underwater hazards like tree stumps, submerged rock islands, etc.? If so, an aluminum prop is much more forgiving if you hit something with it...the blades flex more than stainless and will typically bend or break....stainless has less flex, thus better performance but isn't very forgiving if you hit something with it. The center rubber hub system if you have it typically is designed to strip out first and save the drive itself, but not always.

What is your engine running at for wide open throttle with the current prop? What does the specs say for your engine is the allowable top end of that wide open throttle? My R3 has the Volvo 350 which has a wide open throttle spec of 5800 rpms. It is propped with the dual prop FH6 prop set. So in order to test whether this is the correct prop set for my boat, I would open it up to wide open, let the rpms max out and see where they are. If I can't get to 5800 rpms then it means I have "too much" prop....the engine cant turn enough water to allow it to free up and get there. Look at it as a stick shift car or truck and you are lugging the engine in too high of a gear for the demand you are placing on it...now, on the other side if you do wide open throttle and immediately hit the rpm max for your engine specs, then you don't have enough prop....meaning you could go up to a 23 pitch 3 blade or more. Now, if you increase blades, typically you will have to lower pitch. A 4 blade will push more water than a 3 blade of equal pitch...a 5 blade will push even more. I actually carried 2 props in my Monterey...a 21 pitch 5 blade stainless that was my "lower elevation" prop....and the same prop but in a 19 pitch for "higher elevation".

My suggestion would be to research your engine first...find the specs on it and see what wide open rpm max is supposed to be. Then take the boat to the lake on a calm morning where you can safely open it up and get a good run in....see what it does. If you immediately hit the rpm max...then you know you can add either more pitch or same pitch but more blades. If it is under the rpm max....then you already have too much prop, and need to go with a lower pitch prop.

Regardless, you will find give or takes on any changes you make...if you have a mercruiser drive, the Mercury website has a prop selector tool that you can "ballpark" based on engine, boat size, weight, altitude, etc. It's usually pretty close in my experience. At minimum after checking your specs and doing a run....buy a stainless prop of same pitch and blades and try it...I've played with Stilleto, Vengeance, High Five, Enertia and Rev 4 before settling on my High Five. If you don't already have a spare prop, this is a good excuse to have one. The mercury prop selector will also allow you to put in kind of what you want...best performance, good overall, etc. You might also check with your local dealership(s) and see if any of them have a buy and try program. Pic below is my old High Five. Hope this helps!

[Big Block Power]

Great write up. Now get in your boat and see what your wot is!
This is your prop you currently have.