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ContinuousWave: Post-Classic Whalers
295 Conquest Prop test
|Author||Topic: 295 Conquest Prop test|
posted 01-04-2006 10:55 AM ET (US)
I have been running the stock 3 blade 17 pitch Merc Mirages on my conquest with OPti 225's. I recently bought a set of Revolution 4's in 17 pitch to try on the boat. What a diference!!! The boat was actually faster on the top end and was able to stay on plane much lower in the RPM range. With the Mirages I was only able to see 38 knots WOT, with the Rev 4's I saw 40 knots with 5 people on board and the curtains up!!! I am not easily impressed with prop changes but I have to admit that I was plaesantly surprised.
posted 01-04-2006 04:59 PM ET (US)
Sounds great. For others who may like the information in the future, could you post the prop diameter and speed vs. RPM if you have that info. By the way, I thought you sold your Conquest. Is this another boat?
posted 01-04-2006 07:33 PM ET (US)
The buyer failed to produce the cash so I am still with the Conquest. I am about to repower with F250 Yamahas and change the Generator to diesel I just have to survey the fuel storage logistics. I will take more detailed notes in the coming weeks on prop diameter and rpm's etc.
posted 01-04-2006 08:17 PM ET (US)
You'll be real happy with the 4 Strokes. You may need to go to a 19" Rev 4 though. I can turn my 17" Rev 4 6000 with my 225s. I got about the same improvement when I changed from Mirage props. I run about a knot slower than you, but my bottom paint is fairly rough.
Kemp Lindsey / Boise,ID
posted 01-05-2006 03:17 PM ET (US)
dhlaw, I am repowering my Outrage 28 with Yamaha F250s. I also had 17" mirage 3 blade props and have never been satisfied with the performance most particularly the inability to plane at lower speeds. I haven't chosen the props for the Yamahas yet but I am inclined to move to 4 blade units. We'll see when the work is done. Pricey move but I do like the boat.
posted 01-05-2006 04:19 PM ET (US)
Dave -- the Mirage 17P has a 15 1/2 inch diameter and the Revolution 4 17P has a 14 5/8 inch diameter. Blade shape is quite different. The Rev 4 is quite a bit heavier as well.
I saw improvements switching from a pair of 17 Mirages to a pair of 17 Revolution 4s below about 32 MPH. My top speed dropped by about 2 MPH, WOT RPM were down about 200 to 300 and peak fuel economy declined just slightly but it was more uniform throughout the cruising speed band due to the better cruising traction provided by these propellers. Subjectively, the slow plane handling, the overall ride and docking control were much improved over what they were with the Mirages. To sum it up, performance below 30-32 MPH was much improved but performance above 30-32 MPH was not.
The Rev 4s top speed increase on the 295 Conquest suggests that the Mirages were slipping alot and really weren't enough propeller to carry the Conquest load.
posted 01-05-2006 05:13 PM ET (US)
Peter - I am beginning to think your experience with the Mirage vs Rev-4 is not typical, as my own experiences are the same as others are reporting here - more top end, tremendous hull lift, better acceleration, and lower RPM mid range cruising and planing. It could be the Whaler 27 hull and WD "trim tab effect" just don't respond to the prop as well. Who knows. My 25 Outrage became a whole different animal when I installed them.
For all arouond offshore boating, the Rev-4 has got to be one of the best propellers on the market today. I am seeing them all over the place, on all types of offshore hulls and all engine brands
posted 01-05-2006 06:58 PM ET (US)
Larry -- My experience is exactly how Mercury characterized the Rev 4 versus the Mirage, that is...a loss of a couple of MPH and a few hundred RPM. It's also consistent with results I've seen reported by many others who have run both props. Rather, I think my experience is quite typical, not atypical. Your experience may not be typical considering your 25 Outrage configuration is not typical.
My 27 Whaler WD has no "trim tab" effect. The Whaler Drive should really be viewed as a hull extension. The keel of the V of the hull is carried all the way to the end of the Whaler Drive although there is a step at the boat transom/Whaler Drive interface so the keel line actually does step up a few inches for the most rearward 3 feet. The 27's WD has built-in trim tabs. The boat rides like a 29' 7" boat, not like a 26' 7" boat with 3 foot trim tabs extended somewhat.
I've run a number of different three blade propellers and on calm water, and above the 30 to 32 MPH threshold they all perform better than the Rev 4s. The Rev 4s, like most 4 blade propellers, really shine in conditions requiring traction like rough water when you are trying to maintain a slow plane. Top speed is clearly not its strong attribute.
posted 01-06-2006 10:00 PM ET (US)
Are your 225's four strokes? which boat? a 295?
I am running stock 3 blade 17's on my CQ 275 w/ Yam F200's. I am curious about 4 blade props to help on the <30mph range, but the dealer is telling me the boat planes extremely with the 4 blades making it harder for the boat to build rpms.
Capt. Tully Mars
posted 01-06-2006 11:02 PM ET (US)
Mine is a Conquest 28/295. The motors are Mercury/Yamaha 225 4 strokes. The Rev 4s accelerate quicker than the Mirage 3 blades. The main thing I like is that you can hold plane as slow as 17 KTS and if you come off plane a little power and you're right back up. With the Mirage you would fall off plane climbing a swell at about 20 Knots and then it would be slow getting back on plane. The props don't break loose in rough water like the 3 blades. With full fuel I cruise at 4400 to 4600 Rpm which comes out 23-25 Knots.
posted 01-07-2006 04:27 PM ET (US)
Peter, my Whaler ran about 5 mph faster top end with same pitch Rev 4-s over Mirage Plus. The difference in the two props was condiderable. I know some others that have reported the same thing. Only on the huge cube stern drive go-fasts does Mercury indicate the Mirage Plus is a faster prop than a Rev-4. I think in my case the boat gains the extra speed due to the total hull lift I get from the Rev-4s. The Mirage did not do this. And on that big ol' bow heavy 27 Whaler WD of yours, with engines way back there on that bracket, the Rev-4's may not be able to lift it enough to gain the extra speed. The Mirage is billed as a prop for boats with "big power" and high top end potential, and those old 225 Ficht's may not fit the bill on a boat rated for 600 HP. You need a pair of pair of 275 Verados to get some more weight in the stern!
The Mirage is not a new prop design, and I think these newer designs may run better now. Hence the "Enertia" and introduction of the Tempest Plus in counter rotation. It sounds like both of these are going to be faster props than the Mirage Plus in twin configuration.
posted 01-07-2006 10:38 PM ET (US)
Most interesting. It re-vitalizes my interest in 4 blades.
Right now my boat under 3600rpm (about 24mph) is the minimum plane. I would really like to get this lower of course for the rough water.
Since I almost never run wide open because of the massive fuel consumption I want to optimize my crusing fuel mileage.
Did anyone see cruising mileage increase with the 4 blades?
Right now I cruise at 30mph around 4200rpm. According the prop calculator I have very little slip in my current arrangement, but I still have a feeling 4 blades would help. I just haven't found the right path there.
Capt. Tully Mars
posted 01-08-2006 10:30 AM ET (US)
My 305 Conquest will hold a plane in big seas as low as 13-14 knots with Yama-Merc 225's and Rev 4's. Often 14 knots is the maximum comfortable cruise in rough seas. The alternative with three blade props would be to mush along at sub planing speeds, listening to the props cavitate when they are trying to haul the boat up a trough. The Rev 4's almost never cavitate even when mushing along at 10 knots.
The 305 is a different hull design than the 28-295 Conquest, the hull is full length rather than notched and will hold a plane at lower speeds.
Anyone running in heavy seas will instantly like the Rev-4's even if they loose a couple of mph and a bit of fuel economy and not regret their decision to drop $1000+ on a prop change.
I had a Mirage 3-bladed prop on my 23 Conquest and a single 225 Optimax. Minimum planing speed was 19 knots, much too fast for any kind of rough water. I believe the little Conquest would have planed at around 15 knots with a Rev 4, but Mercury didn't make one at that time with a low enough pitch.
posted 01-08-2006 02:30 PM ET (US)
Capt. Tully... -- I did not experience a cruising mileage increase switching from the Mirages to the Revolution 4s. However, I can maintain plane down to 14 MPH which was something that was impossible to do with the Mirages. The Rev 4s do not break free like the Mirages do in rough water. Overall cruising ride comfort in a chop is better because the Rev 4s are getting consistent traction, something the Mirages were not able to do probably because they were trying to lift the bow too much. I think anybody running a Conquest 260 or above with twin outboards would find the slower speed improvements coming from the Rev 4s far outweigh any loss of top speed.
posted 01-08-2006 05:03 PM ET (US)
DHlaw appears to be out fishing (good for him!)..... his boat is a beautiful 295 with twin Mercury Optimax engines FYI.
Peter: Thanks for adding the prop diameter info for those who read this later.
posted 01-09-2006 09:24 PM ET (US)
Guys, you all really want me to just rush out and get some Rev4s!!!
The description of mushing at half plane is exactly what happens with my boat in rough water. To be able to back down and stay on a plane I would think mileage would improve since you weren't always pushing the boat back on plane.
Ok, I want to just summarize some of the statements up top...
It seems most of the Conquest fellows here saw a minor speed increase (dhlaw, kglinz, and LHG) with Rev4s being the same pitch of 17" and a diameter decrease.
Ok, you guys are all running F225's, I am running True Blue (actually grey) Yamaha F200's though. My SST props are 17" also turning about 5800rpm at WOT. I guess if I did the same thing, went to a 17" Rev4 with a 14 5/8" or 14 1/2" diameter I might drop to about 5600 RPM at WOT. Would this be lugging the boat too much?
Or, do you think there is too little difference between the HP the motors, F200 vs. F225, to worry about much difference in performance. From what I have read the real HP difference between the engines is around 12 hp.
I have been wanting to hear this type of real world experience for a long time, I am really hoping for some of your great opinions.
Capt. Tully Mars
posted 01-09-2006 10:57 PM ET (US)
I don't think you would have less performance from a F200 considering your boat is a little lighter and narrower. I think I actually can turn the Rev 4s higher in RPM than the Mirages. This is probably because I trim the motors further out with the Rev 4s. I trim the motors out until I reach max speed, and to a point that the bow is very "light". Just slightly before a porpoise. I could never reach a point of trimming that far, bow up, with the Mirage props. The Mirages would break loose before reaching that trim angle. Of course when your talking trim, every boat is a little different. I've got 200 feet of chain in the bow locker, 5 AGM batteries at the transom, Air conditioning and a generator.
posted 01-10-2006 01:48 PM ET (US)
Kemp - I found the same thing when comparing Rev-4's to Mirage Plus - I could turn the 21" Rev-4's up higher, and get considerably faster top end than same pitch Mirage Plus. I credit this to the extra lift from the props.
Tully, I should say that I do not have a Conquest, but rather a relatively light weight Outrage 25, with a high HP to weight ratio from the twin 200 Merc EFI's (putting out a true 215 HP I have been told by a Merc engineer). So my own experiences and success with the Rev-4's may not be the same as others here.
I should say, also, that I recently saw a big US Coast Guard Safe Boat being re-powered from Honda 225's to 250 Verados, and Revoultion-4 props were being installed.
posted 01-11-2006 11:01 AM ET (US)
I saw a new Safeboat on a truck, with Verados on the hiway yesterday.
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