[craig223]

After the longest winter in my life, splashdown date was tuesday for some prop testing. As some of you know, I bought a 223 last December and got to go out twice before winterization. The boat saw a top speed of 68.7[email protected] in December with a Hydromotive 4-blade 23P and about 50 gallons of gas. The motor is a Merc 454/425 with a little bigger Ultradyne cam and Gil exhaust. I'm thinking about 460 to 470 HP. The Mercury website suggested a Mirage Plus 25P so I bought one to try. Here is the results. Any help would be welcomed

All speeds are GPS- about 3.5 less than the speedo reads

25 Mirage Plus

3000 RPM = 40.7
3500 =49.8
4000 =58.6
4400 WOT =64.2

23 P Hydromotive 4 blade

3000 RPM =35.1
3500 =43.7
4000 =52.4
4500 =61.3
5000 WOT =64.7

Both tests were done with a full tank of gas (79 gallons) and just me onboard (200 lbs.) plus a cooler

 

[Speedwake]

Do you attribute the faster speeds in December to colder, denser air?


- jeff

 

[craig223]

It was about 65 degrees with about 50 gallons of gas as opposed to 98 degrees yesterday and 79 gallons.
I lost 200 RPM's and 4 MPH. The only mods over the winter was the addition of a drive shower.

 

[Speedwake]

I put a drive shower on mine Saturday. It was a mess drilling 3/4" holes though 1/2' thick stainless steel on the hydraulic steering plate that's bolted to the outdrive. It's all for the best though.

 

[Canada Jeff]

It looks like that Mirage would work nice for you if you had it labed or if you went down a pitch bringing your RPMs up to 5000 or so. rule of thumb merc uses is one pitch up or down changes your RPM 250 to 300. I ran a mirage on my last boat and thought it worked great. You should be able to trade that prop if you just got it.

 

[craig223]

That means that a 23 Mirage Plus would put me at 4900-5000 and labbing it would give me 5200 right?

 

[Canada Jeff]

That sounds right to me. I wouldn't lab it though. I'd keep the stock Mirage 23p and turn 5000. You never know you could hit a day when the water is like glass and you have a chance to trim out farther getting the boat out more, then you'll find yourself turning 5200. Thats the sweet sound! Also lab fin props don't take the abuse a stock will. Hitting some thing like a stick with a lab fin could mark the cutting edge just a bit, then you fix that little mark and so on and so on. The stockers are a little more forgiving, not to mention cheaper. Thats just my opinion! Good luck