Finding Right Prop - Merc Revolution 4, Stiletto BP 2, Turbo Ultima 4 ???

[tpenfield]

I have been doing lots (and lots) of research regarding a new propeller for my Formula 24 ft cuddy, and I wanted to get any first hand knowledge or expertise before I make a purchase. I currently run a 3-blade and I have been shopping for a 4 blade (stainless steel).

Boat = Formula F-242 SS, 24 degree deadrise, Mercruiser 7.4L (330 hp), Bravo 1, 4800 lbs. dry, 96 gallon fuel tank.

Current Prop = Mercury/Quicksilver Mirage (old version), 14.75" dia. x 21 " pitch x 3 blades

WOT = 4300 RPM, 43 MPH (mfg spec is 4400 - 4600 rpm, so it is a bit on the low side)

Usage = Cruising & occasional water sports.

I'd like to improve the hole shot, minimum planing speed and mid-range performance. Top end is not too much of a concern, but I would not want to have it suffer too much. I'd like to see if I can get the RPM's up in the 4500 range.

I have been trying to find something with a 20" or 19" pitch and have considered the following props:

Mercury Revolution 4 - 14.625" dia. x 19" pitch x 4 blades (expensive, and popular, New goes for $500+, and used is $250 - $350)

Stiletto Bay Pro II - 14.25" dia x 20" pitch x 4 blades (can get new for around $300, used market is sparse)

Turbo Ultima 4 - 14.24 " dia x 20" pitch x 4 blades (can get new for around $300, used market is sparse)

I have also checked out a few of the PowerTech props, and Turning Point props.

I have been shopping eBay for used props, figuring that if I am wrong about the prop, I can re-sell it for similar money as I paid for it. The Merc Rev 4's are a hot item and tough to get/win on eBay, but there seems to be a steady flow of them coming up for auction. The other bands are few and far between, but the cost of them new is much lower.

I am leaning towards getting a new Stiletto BP II. There seems to be 2 versions of Stiletto props (built-in hubs and replaceable hubs) the versions have different part numbers (ex #15420 vs. #805420). There seems to be some discrepancies on the published diameters for the props. (some sources say 14.0 " and others say 14.25". I called Precision Propeller Industries, Inc and asked about the props, they told me that they were both 14.25" (???) Can anyone clarify that further? I'm concerned about going too far down in diameter.

Any comments about these props or advice as to which may be better over the other. TIA.

 

[John_S]

Re: Finding Right Prop - Merc Revolution 4, Stiletto BP 2, Turbo Ultima 4 ???

Given your location, I got to believe there is a prop shop that you could work with that will allow to try different props and dial it in for your boat and load. Yes, probably a little more expensive, but you will get exactly what you want.

I can't comment on any of the specific characteristics of the props you are considering and/or how those characteristics may benefit or detract from your particular boat. In general terms, I think you need to drop down another inch of pitch. Adding a blade and dropping one inch of pitch, will probably have you at or close to your current wot rpm. Again, thats in general. Cupping on those props could mean you need drop more pitch.

Again, working with a prop shop, you could get dialed in within a day or two, and then enjoy the rest of the season, instead of spending allot of time on ebay. Time on the water, hard to quantify the $.