REVOLUTION4 versus VENSURA - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Performance
  REVOLUTION4 versus VENSURA

search | FAQ | profile | register | author help

Author Topic:   REVOLUTION4 versus VENSURA

pineapplepig posted 08-27-2006 06:23 PM ET (US)
I am currently spinning Mercury Revolution4 19-inch pitch propellers at only 5,550-RPM on twin small bore 200 E-TEC mtoors. Would switching to a Vensura be a better bet for these engines? Would I have to go up to a 21-inch pitch as the blades are much smaller?
jimh posted 08-28-2006 08:09 AM ET (US)
It may be helpful to know what boat is being discussed for this application.
Tom W Clark posted 08-28-2006 10:22 AM ET (US)
Yes, a pair of 21" Offshore/Vensuras will turn approximately the same RPM as a pair of 19" Revolution 4s.
pineapplepig posted 08-28-2006 02:10 PM ET (US)
In this instance not a Whaler. Whilst I do run an Outrage 19, this is a 245 Edgewater with a not dissimilar hull design given that Whaler and Edgewater were designed by the same man.
jimh posted 08-28-2006 08:45 PM ET (US)
If the application is a big boat, the REVOLUTION4 propellers will probably have lower SLIP and work more efficiently than the smaller diameter VENSURA propellers. I think this is part of the reasoning behind the recommendation that Mercury gives regarding the VENSURA propeller that it is intended for lower horsepower motors (135- to 175-HP).
My experience with the REVOLUTION4 is quite limited, but I found the propeller to be a very large and very heavy propeller. It seemed to overwhelm the outboard gear case. However, it had very good performance; it had no trouble hanging on to its grip without cavitation, and its SLIP was low.
I also think that you need to select a propeller that is tweaked for the speed range in which you tend to operate. As the pitch goes higher, the propeller is tweaked for higher speeds. Thus a 21-inch propeller is probably intended to give optimum performance at a higher speed (than the speed at which a 19-inch propeller is intended to give optimum performance).
If you put on the 21-inch pitch propeller, you may find that the fuel economy is not as good at the lower speeds you might be using. However, that is subject to testing, for sure, and you might find that running higher pitch propellers allows the engines to run at lower engine speed for a particular boat speed, thus boasting fuel economy. It depends on the engines and how much torque they have and their gear ratio. And on the propeller design, of course.
If you do make the comparison, it would be interesting to hear of the results.
pineapplepig posted 08-29-2006 04:22 AM ET (US)
Thanks Jimh, I think what you say is spot on. I am getting virtually no slip with the Rev 4 and running 34MPH @ 3,500 revs and getting 2.4mpg which is very good for 400 HP and would be where the bulk of my running would be. Interestingly it is about the same MPG as the same boat with Vensuras running twin F150's but they are running @4000. What I have actually decided to do is try a pair of 3 blade Merc Enertias 21's as an alternative as that way I may see a substantial different set of figures and a different feel. I will post some figures but it will not be for a while.
andygere posted 08-29-2006 11:22 AM ET (US)
Pineapplepig,
Any problems with hard shifting or gearcase thunking running the Rev4 props on your small block E-
TECs? I'm considering a Rev4 on my Outrage 22 Cuddy/E-TEC 200, but was concerned about Jimh's experince (noted above) with this prop.
pineapplepig posted 08-29-2006 01:19 PM ET (US)
To be absolutely honest, I am yet to get my hands on the boat-all the info is coming back from my dealer who has been doing extensive sea trials which I have been monitoring closely. I did specifically ask him about the 'clunk' shifting, and he said he did not remark particularly on it. He did say you had to be positive putting it into gear. He also tried a BRP Cyclone and felt the Rev 4 was all in all a great prop, and the best of the two and gave terrific lift and great overall feel. What I have learnt is that it is a very efficient prop but I would be tempted to try the Vensura as well in your case, although mid range cruise might not be so efficient.

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: REVOLUTION4 versus VENSURA
pineapplepig	posted 08-27-2006 06:23 PM ET (US) I am currently spinning Mercury Revolution4 19-inch pitch propellers at only 5,550-RPM on twin small bore 200 E-TEC mtoors. Would switching to a Vensura be a better bet for these engines? Would I have to go up to a 21-inch pitch as the blades are much smaller?
jimh	posted 08-28-2006 08:09 AM ET (US) It may be helpful to know what boat is being discussed for this application.
Tom W Clark	posted 08-28-2006 10:22 AM ET (US) Yes, a pair of 21" Offshore/Vensuras will turn approximately the same RPM as a pair of 19" Revolution 4s.
pineapplepig	posted 08-28-2006 02:10 PM ET (US) In this instance not a Whaler. Whilst I do run an Outrage 19, this is a 245 Edgewater with a not dissimilar hull design given that Whaler and Edgewater were designed by the same man.
jimh	posted 08-28-2006 08:45 PM ET (US) If the application is a big boat, the REVOLUTION4 propellers will probably have lower SLIP and work more efficiently than the smaller diameter VENSURA propellers. I think this is part of the reasoning behind the recommendation that Mercury gives regarding the VENSURA propeller that it is intended for lower horsepower motors (135- to 175-HP). My experience with the REVOLUTION4 is quite limited, but I found the propeller to be a very large and very heavy propeller. It seemed to overwhelm the outboard gear case. However, it had very good performance; it had no trouble hanging on to its grip without cavitation, and its SLIP was low. I also think that you need to select a propeller that is tweaked for the speed range in which you tend to operate. As the pitch goes higher, the propeller is tweaked for higher speeds. Thus a 21-inch propeller is probably intended to give optimum performance at a higher speed (than the speed at which a 19-inch propeller is intended to give optimum performance). If you put on the 21-inch pitch propeller, you may find that the fuel economy is not as good at the lower speeds you might be using. However, that is subject to testing, for sure, and you might find that running higher pitch propellers allows the engines to run at lower engine speed for a particular boat speed, thus boasting fuel economy. It depends on the engines and how much torque they have and their gear ratio. And on the propeller design, of course. If you do make the comparison, it would be interesting to hear of the results.
pineapplepig	posted 08-29-2006 04:22 AM ET (US) Thanks Jimh, I think what you say is spot on. I am getting virtually no slip with the Rev 4 and running 34MPH @ 3,500 revs and getting 2.4mpg which is very good for 400 HP and would be where the bulk of my running would be. Interestingly it is about the same MPG as the same boat with Vensuras running twin F150's but they are running @4000. What I have actually decided to do is try a pair of 3 blade Merc Enertias 21's as an alternative as that way I may see a substantial different set of figures and a different feel. I will post some figures but it will not be for a while.
andygere	posted 08-29-2006 11:22 AM ET (US) Pineapplepig, Any problems with hard shifting or gearcase thunking running the Rev4 props on your small block E- TECs? I'm considering a Rev4 on my Outrage 22 Cuddy/E-TEC 200, but was concerned about Jimh's experince (noted above) with this prop.
pineapplepig	posted 08-29-2006 01:19 PM ET (US) To be absolutely honest, I am yet to get my hands on the boat-all the info is coming back from my dealer who has been doing extensive sea trials which I have been monitoring closely. I did specifically ask him about the 'clunk' shifting, and he said he did not remark particularly on it. He did say you had to be positive putting it into gear. He also tried a BRP Cyclone and felt the Rev 4 was all in all a great prop, and the best of the two and gave terrific lift and great overall feel. What I have learnt is that it is a very efficient prop but I would be tempted to try the Vensura as well in your case, although mid range cruise might not be so efficient.