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Author Topic:   Conquest 23 w/ 225 Optimax Prop.
RonCT posted 09-09-2003 09:22 AM ET (US)   Profile for RonCT   Send Email to RonCT  
My other Whaler is a 2001 23' Conquest with a 225 Optimax. She came with a Mirage propeller and the only complaint I have about the boat is that it takes a good long while to get on plane - with lots of bow lift to boot.

Any suggestions on trying another propeller to reduce this problem? Mercury's web site shows a Revolution 4 (4-blade) that sounds interesting. Any advice is appreciated.

Email to ronjaneczko@sbcglobal if you like.

Peter posted 09-09-2003 10:23 AM ET (US)     Profile for Peter  Send Email to Peter     
Ron - it would help if you told us what the pitch of your Mirage propeller is.
jimp posted 09-09-2003 11:24 AM ET (US)     Profile for jimp  Send Email to jimp     
RonCT -

Good question. I just repowered my 1990 Revenge 22 W/T with a 2003 Merc Optimax 225 in May. The engine came with a 19" 3-blade aluminum prop and I had them throw in a 17" Revolution-4 4-blade stainless as part of the deal (of course I paid more!). Real interesting results:

19" aluminum 3-blade prop:
Cruise: 3750 rpm = 27.7 knots = 3.1 nautical mpg
Top 39 knots, decent acceleration.
WOT 5250 RPMs

17" stainless Revolution-4 4-blade prop
Cruise: 3800 rpm = 24 knots = 2.8 nmpg
Top 41 knots, great acceleration, my arms are 4" longer!
WOT 5500 RPM

I really like the 27.7 knot cruise and 3.1 nmpg, so my Revolution-4 is sitting in my baitwell as a spare. The dealer wanted $600 for the Revolution-4, but I found it on the internet for $440+$20 shipping.


Peter posted 09-09-2003 01:42 PM ET (US)     Profile for Peter  Send Email to Peter     
JimP's reports here illustrate an important point in selecting a propeller. What do you want out of your propeller? Good cruising or top speed. This is a question that is asked by Mercury's prop selector.

Yamaha advertises that its Saltwater Series propellers (what I have on my Yamaha 225/Revenge 22) is designed for cruising. If I wanted to squeeze out more top end then a different propeller would probably be desirable but I would be giving up some efficiency at cruise. Since I mostly run at cruising speeds and rarely WOT, the Saltwater Series propeller is a suitable choice.

lhg posted 09-09-2003 06:40 PM ET (US)     Profile for lhg    
For both of the boats mentioned above, I would think the 4-bladed "Offshore Performance" would be appropriate. It seems inconceivable to me that the Revolution, which is a speed prop, would be appropriate for a Revenge. A Mirage would be far superior to an standard aluminum on a 225 Optimax also.

However, if Whaler shipped a Mirage with the 23 Conquest, I would assume they would do this on the basis of their testing. It could be that the 225 is marginal HP for the boat, and twins are needed.

RonCT posted 09-12-2003 11:22 AM ET (US)     Profile for RonCT  Send Email to RonCT     
Thanks guys,

My 01 Conquest came with a 15 1/2" x 17" Mirage Plus on the 225 Optimax.

Maximum operating range is 5,750 RPM, though I cannot attain that. I understand going to 4 blades (Revolution 4) would give me more hole-shot and reduce maximum RPM by 50-100. So, if I got the same size R4 prop, I would get further away from maximum. The R4 comes in 14 5/8 x 17, which is slightly less diameter than stock 15 1/2". Does anyone know what the effect of that is (if any)? Or does everything only have to do with pitch?

Peter posted 09-12-2003 12:06 PM ET (US)     Profile for Peter  Send Email to Peter     
Ron - forgot to ask: (1) what is your WOT rpm when the boat is most typically loaded for you and (2) what is your WOT speed?
RonCT posted 09-15-2003 08:37 PM ET (US)     Profile for RonCT  Send Email to RonCT     
I'd have to run the boat again to get exact figures. I recall about 40 MPH at 5300 RPM, which is lower than I would expect. I'll try some runs on Wednesday (before I double up my lines in preparation for the storm - have to pull out the Sport 13 that I have moored in front of our cottage).
Peter posted 09-16-2003 07:31 AM ET (US)     Profile for Peter  Send Email to Peter     
Assuming your recollection is good on the numbers you post, your 225 might be a candidate for a 15 inch pitch propeller. My recollection is that the 23 Conquest is a fairly heavy boat possibly having a dry weight that could be 1000 lbs more than a 22 Revenge.

I think you should see if you can get someone to loan you the correct size stainless steel 15 inch pitch propeller and give that a try. See where your WOT rpm and speed are. It will certainly help the hole shot and will reduce the prolonged bow lift because it won't take as long to get on plane. It should put your WOT rpm at the upper end of the range near the 5700 mark.

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