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Author Topic:   4 Blades
dogface posted 08-21-2002 11:07 PM ET (US)   Profile for dogface   Send Email to dogface  
Put 4 blades on my Conquest. Rev 4s at 17 pitch. They are incredible, on plane faster and a top speed of 42.5 with fuel cells topped off, Cindy and myself. Thanks to Skip at Gulf Coast Marine in Homossassa for setting me up with a pair to try.
msc posted 08-22-2002 01:10 PM ET (US)     Profile for msc  Send Email to msc     
Dog, what size is your conquest? What size are your engines?
dogface posted 08-22-2002 08:26 PM ET (US)     Profile for dogface  Send Email to dogface     
28 Conquest when I bought it, now a 295. Twin 225 Optis. The 3 Blade props with the motors slipped too much and had a hard time getting on plane. The boat responds noticably better.
lhg posted 08-22-2002 08:43 PM ET (US)     Profile for lhg    
Mercury recommends the 4 bladed Offshore Performance line of props for your boat, not the Revolution go-fast props, which are for Stern drives, and only offered in 19-23" pitch. With 17" props, you must have the "Offshore" props? But as you say, I hear they are excellent for heavier boats requiring lots of hull lift.
tully_mars posted 08-22-2002 08:47 PM ET (US)     Profile for tully_mars  Send Email to tully_mars     
What's your max RPM now? And what pitch were your 3 blade props? How much did your diameter change? I'm thinking of going to 4's myself on a 23' Conquest.

Tully Mars

BMR posted 08-22-2002 10:32 PM ET (US)     Profile for BMR    
I have also heard of people going to the Revolution 4 propellers on heavier boats. They have a larger blade area than an offshore and should carry a load better because of this. I think there is a 17" pitch available as well as the sizes noted in one of the other replies.
dogface posted 08-23-2002 03:17 AM ET (US)     Profile for dogface  Send Email to dogface     
The 3 blades were also 17 pitch so I was a bit leery but the boat came up to 5400 RPM nicely. The difference is dramatic. Cant remember the diameter. The amount of slip was obvious with the 3 blades. The motors seem to handle the new props fine.
msc posted 08-23-2002 10:16 AM ET (US)     Profile for msc  Send Email to msc     
Dogface, thanks for the info. I'm running 3 blades (15[14.5] x 17). I have a lot of slip when coming up on plane and have given much thought to 4 blades. When I questioned the dealer they said they tried them but went back to 3. It seems counter intuitive to use 3 blades with 28 whalers with their weight and horsepower. I'm going to try 4 blades.
diveorfish posted 08-27-2002 05:03 PM ET (US)     Profile for diveorfish  Send Email to diveorfish     
Since we are on the topic of props, I hope it's okay to expand this the subject a bit to include smaller Whalers like 23 Outrages or 23 Conquests running twin 135 Optimaxs, to be exact. Currently, I am running twin 135s and have a 14 x 17 pitch SS props on my 23 OR. I was thinking that moving up to a 19-pitch prop would give me a little more top end and better fuel economy without sacrificing adequate acceleration. Of course I could be completely wrong. It just seems like my engines have a way too easy of a time getting to the highest rpm range. Also, would a 4 bladed prop be worth consideration for smaller Whalers like mine? For a newbie like me, knowing the pros and cons of these various prop configurations would be most helpful?
lhg posted 08-27-2002 06:22 PM ET (US)     Profile for lhg    
The propeller section on Mercury's website is pretty good for descriptions and applications of their various prop designs. You're probably running Mirage props, and it could be that the 4 bladed Offshore would work for you. Excess RPM's determine whether you need more pitch or not. You do not want Vengeance or aluminum props on your boat.
bsmotril posted 08-27-2002 10:25 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
I have twin opti 135s on a conquest 23. I would be interested in trying a pair of Stilleto or similar props with lesser diameter than the Mirage 17s I have now. The Mirage seems like a bit of overkill on a Whaler. I have a hardtop on mine, and it will easily bump the rev limiters with 3 aboard and 1/2 fuel. The previous boat I owned had a single Merc 175 with a 17" Mirage. I tried a 4 bladed Merc 17" offshore for a while. The hole shot was much better, but all speeds were 2-4 mph lower than the Mirage for any given RPM. The 4 blade did a better job of holding the boat on plane at a lower speed. I wished I had an 18 or 19 inch 4 blade offshore to try in place of the 17"Mirage as that would probably have gotten me in the ball park where I wanted to be. Alas I sold that boat and bought a Whaler before I got it dialed in. The one thing that was really amazing was the smoothness of the 4 blade versus the Mirage. It made the boat seem turbine powered with minimal vibration.
JoeyP posted 08-28-2002 12:49 PM ET (US)     Profile for JoeyP  Send Email to JoeyP     
I'd like to try a pair on my 275 Conquest with twin 200 Opti's. The problem is finding a dealer who has a pair to test. I researched these props this past winter and contacted BW. They told me they hadn't tested them on any of the Conquests as of yet. I guess they were leaving it to the consumer to test first. These Rev 4's caught my attention because they claim to improve out of the hole performance on heavier boats powered by larger outboards.
dogface posted 08-28-2002 02:49 PM ET (US)     Profile for dogface  Send Email to dogface     
Skip at Gulf Coast Marine hooked me up with a pair to try and purchase if I like. Skip is my Ace Mercury man out of Homossassa. I had talked to Skip last winter about my concerns with prop slip and waisted energy with the 3 blades. He gave me a call in the Spring and told me he was working with Whalers Merc man John (cant remember last name) and they also had the same concerns I did about getting on plane and the general uneasyness I had with the 3 bladed props. Skip called me and said he had em so I arranged to have him install them during yearly maintanence. Tried em, loved em, bought em,,, kudos to Skip at Gulf Coast for his diligence.
JoeyP posted 08-28-2002 05:35 PM ET (US)     Profile for JoeyP  Send Email to JoeyP     
Sounds like a good deal Dave. I'll have to try my dealer here in Jersey to see if can get a try at them. I would imagine they cost a good buck. I know the bow rise on these conquests are initially high when throttling up out of the hole.

Dave, did you lose any top end speed?

dogface posted 08-29-2002 08:10 AM ET (US)     Profile for dogface  Send Email to dogface     
only lost 2 MPH at WOT.
VMG posted 08-29-2002 10:16 AM ET (US)     Profile for VMG  Send Email to VMG     
Diveorfish and bsmotril -- Am interested in knowing height your engines are mounted at -- #1 or #2. I've got OR 23 w/twin Yam 150 EFIs that I think I can get some more out of if I raise them one notch.
bsmotril posted 08-29-2002 06:57 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
My motors are mounted as low as you can get. There is less than an inch clearance between the top edge of the mounting bracket and the top of the transom.
diveorfish posted 09-04-2002 01:39 PM ET (US)     Profile for diveorfish  Send Email to diveorfish     
VMG: sorry it topok so long to respond by my engines are on #2 or second from the top.
VMG posted 09-05-2002 01:38 PM ET (US)     Profile for VMG  Send Email to VMG     

My suspicion has been that my engines are running a little low in the water -- mostly an eyeball impression based on where the lower units are once the boat's on-plane. Too much water splashing around back there --looks like I can raise them one number and still keep the plate wet.


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