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Vensura prop on E-Tec 175HP
kamie	#1  Posted on 10/21/09 - 7:11 PM
Member Personal Page Project Albums Posts: 2975 Comments: 3 Joined: 11/04/05	Well, it was a bit chilly, but dead calm on the river yesterday, so I opened up the E-Tec with my 19P Vensura Prop. I have removed the stern seat but added an extra battery, so net she is about 50# lighter than last year, gas tank was full. The air temp was in the low 60's and the water temp was about 55. Average of two runs at WOT 5625 RPM and 46.5MPH I need to do the runs again to see if I can get the lower RPM's with fuel flow off the engine as my Navman is not registering fuel flow. I have been running this prop all summer and been very happy with the performance. I think I could get higher top end if I removed the bottom paint, which I may try to do come spring. Not sure what else would help at this point. The bottom paint is easily taking 5MPH or more given it's sad state. Here is the thread from last year. Prop Testing 175HP E-Tec
MW	#2  Posted on 10/22/09 - 3:23 AM
Member Personal Page Posts: 1827 Comments: 10 Joined: 01/08/06	I dunno Kam, 46.5 mph is "Singin Along" pretty nice ! Matt
Finnegan	#3  Posted on 10/22/09 - 11:06 AM
Member Posts: 1926 Comments: 16 Joined: 05/02/08	A 19" prop on that gear ratio should be running closer to 50 MPH. Did you ever remove those 2 x 4's from the hull bottom? You must have a lot of drag or slip.
Tom W Clark	#4  Posted on 10/22/09 - 11:59 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	The 19" VenSura/Offshore tends to run like a 17" pitch propeller. That is the just nature of this propeller design. It also needs to be run fully submerged; it will not tolerate a high motor mounting height and surfacing blade tips.
kamie	#5  Posted on 10/22/09 - 1:42 PM
Member Personal Page Project Albums Posts: 2975 Comments: 3 Joined: 11/04/05	Finnegan, the 2x4's are off. the only thing not off is the bottom paint. Tom the prop may in fact be running a bit high. The cavitation plate is completely out of the water at speed. I was going to dry dropping the outboard down a 1/4 inch and see how she ran, assuming I get another flat day on the river. I am happy that with the right prop, she runs above 43MPH which is what the old Merc was stuck at. If I look at buckda's numbers with twin 90's he is running 49MPH and while you could add up the differences at least we are in the same ball park.
Derwd24	#6  Posted on 10/22/09 - 3:06 PM
Member Posts: 1607 Comments: 9 Joined: 05/09/07	Great info in both threads Kamie! I'm going to try a 4 blade prop next season on our Etec and have narrowed it down to the Vensura or Cyclone. Did you notice the AV plate height with the previous 3 blade prop? Am wondering if the 4 blade is giving you more stern lift and that's why it's running a bit high? Dave - 1983 Outrage 22
Finnegan	#7  Posted on 10/22/09 - 4:01 PM
Member Posts: 1926 Comments: 16 Joined: 05/02/08	I have extensive experience with the Offshore/Vensura, also in 19" pitch, on my 21 Ribside with 1988 Merc small bore 150. I completely disagree with Tom's findings, except that it can't take the tansom mounting height that a Laser II can. Needs to run about 1/2 lower. On mine, I ran and tested 4 props for considerable lengths of time. 1. Mercury 19" Black Max aluminum. A surprisingly good prop for an aluminum, but no bow lift gave the boat a rougher ride. Top Speed 45 MPH GPS I didn't expect that. 2. Mercury 19" Offshore/Vensura. A great prop, gave the boat a much better ride because of the lift, but same top speed as the aluminum - 45 MPH. 3. Mercury 19" Laser II, best ride, higher mounting possibility (engine was on jackplate) top speed 47 MPH. 4. Mercury 21" Rev-4. Not really meant for a ribside, but I use these on my 25, so I tried it out. Best top speed at 47.5 MPH, but too much stern lift, and engine could only turn it to 4800 RPM. All others turned 5500. A scary ride! Too much prop for the lightweight banana hull. I finally settled on the 19" Laser II, which is now running on the same engine, on my classic 19 Outrage, same performance as on the 21. I sold the 19 Vensura, and I think Jim McP actually has this prop on his Optimax 150/ribside, and is running over 50 MPH with it. For the 175 E-tec on an 18 Outrage, I would think a 19" or 21" Laser II would be the best for top speed, but otherwise the Vensura is a great prop for that hull. I think an 18 with a 175HP engine should do over 50. My new twin 90 Mercs on my 18 are running somewhere around 53 with 24" Laser II's and 2.33 gears. Edited by Finnegan on 10/22/09 - 4:04 PM
kamie	#8  Posted on 10/22/09 - 4:02 PM
Member Personal Page Project Albums Posts: 2975 Comments: 3 Joined: 11/04/05	The AV plate was in the same spot, since it's on a bracket. I should drop the bracket back down and play with the height. if I calc the slip it's 14.54% which I take to mean that the prop is probably not as efficient as it could be.
Derwd24	#9  Posted on 10/22/09 - 4:20 PM
Member Posts: 1607 Comments: 9 Joined: 05/09/07	Do you mean same spot in relation to the hull or the water at speed? Theoretically if prop A provides more stern lift than prop B, the AV plate would look higher at speed in relation to the water with prop A, all else being equal. Curious to see if you noticed any difference in relation to the plate height above the water with the different props? Dave - 1983 Outrage 22
Joe Kriz	#10  Posted on 10/22/09 - 4:29 PM
Site Owner Personal Page Personal Album Photo Albums Project Albums Posts: 11447 Comments: 452 Joined: 03/18/05	What's the specs on the Renegade Offshore 4 blade prop as compared to the Vensura or the Laser II ????? I used a 14 1/ 2 x 17 Pitch - Renegade Offshore 4 Blade Prop on the Johnson 175 hp on my Outrage 22' Cuddy and showed 40 to 41 mph via GPS.... The Outrage 22' and especially the Cuddy model is much heavier than an Outrage 18'... I don't think my Renegade had any plug system. It was just a standard 4 blade prop from what I remember. I don't see these props listed for sale anywhere so they must have discontinued them.
Tom W Clark	#11  Posted on 10/22/09 - 4:47 PM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	I completely disagree with Tom's findings... chuckle Larry -- I don't where you disagree with anything I've said here. In fact, you're agreeing with me.
Tom W Clark	#12  Posted on 10/22/09 - 4:48 PM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Joe, What specs are you looking for?
kamie	#13  Posted on 10/22/09 - 5:07 PM
Member Personal Page Project Albums Posts: 2975 Comments: 3 Joined: 11/04/05	Dave, I would have to run them again, since I haven't had the Laser II on the boat for all summer, I'm not 100% sure I haven't moved the engine on the bracket.
Joe Kriz	#14  Posted on 10/22/09 - 5:11 PM
Site Owner Personal Page Personal Album Photo Albums Project Albums Posts: 11447 Comments: 452 Joined: 03/18/05	Hi Tom, Not looking for specs for myself but rather stating what the Renegade Offshore 4 blade did on my prior Outrage 22' Cuddy with a 1998 175 hp Johnson on it. Similar motor to kamie's 175 E-Tec except older technology of course. I was quite pleased with the overall performance of the 175 and the prop. The motor was mounted 2 holes up and still had a good hole shot and good top end speed for the size of the motor on the 22' hull. I don't think any other prop could have improved the performance by much if any... I think people might be going too far in trying to fine tune their motor for one type of boating. Unless you are a racer and want only top speed. Mine was used for smooth water and rough water so there also has to be a happy medium. We can't have it all in one prop or one motor height. 1. Good hole shot 2. Best top end speed 3. Rough water (this has to do with motor height) 4. Smooth water (also motor height) 5. Bow lifting 6. Water skiiing 7. etc... And then there are the set back brackets which changes everything.... Lots of variables not even counting the boat itself with or without bottom paint... etc... I know we all want to get the best performance and economy out of any engine and that is what we should shoot for. Recommended range of RPM's for WOT and a happy medium between good hole shot and top end speed or either one of your choice depending on your needs.
Tom W Clark	#15  Posted on 10/22/09 - 6:09 PM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Joe, I have not personally tried the four blade Renegade so I cannot comment on its performance but I do have extensive personal experience with every other model of propeller mentioned in this thread as well as over a dozen others.. In my experience very, very few boat owners try to tune their boat performance for only one thing with the propeller(s); nearly all of us desire good all-around performance. When a Whaler owner does target just one aspect of a boat's performance, it is always somebody trying to see how fast their Whaler can go. Beyond that, there are areas where one may trade one aspect for another. Personally, with my Revenge 25 Walk Through, I've tried to achieve the best possible fuel economy because the boat is a gas hog. I have managed to do this while maintaining a top speed within 2 MPH of the very fastest propellers tested. While it is fun to see how fast our boats can go, once that is accomplished, who cares? I never run my boat at WOT unless I am testing a pair of props. Hole shot is something that is very important to the competitive bass fisherman, but that is not the typical Whaler owner, so again, who cares? My boat will leap on plane if I give it full throttle, regardless of the propeller used. I NEVER do that; my passengers get angry ;-) And I agree that (apart from water skiing) hole shot is not important to the typical Whaler owner. What is important to the typical Whaler owner is how the boat feels while underway. A propeller can make a HUGE difference in this regard, and it is not easy to quantify or qualify, but one knows when it's right. Fuel economy is much easier to quantify by measuring the speed and the rate of fuel consumption. On my own boat a simple switch to better propellers improved my fuel economy by 15 percent, and that's about $200-$300 of fuel savings per season right there. And that is on top of a 2 MPH higher top speed, better grip and a smoother wide as well.
Derwd24	#16  Posted on 10/23/09 - 10:51 AM
Member Posts: 1607 Comments: 9 Joined: 05/09/07	I'm hoping to make it past the 3 MPG mark at optimum cruise with a 4 blade prop. 200 HO has plenty of power for hole shot and decent top end overall, but I've got to believe this engine can do better on fuel economy. Dave - 1983 Outrage 22
Tom W Clark	#17  Posted on 10/23/09 - 11:02 AM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Dave, Start a thread to discuss propping your Outrage 22 and we'll discuss it.
kamie	#18  Posted on 10/23/09 - 4:01 PM
Member Personal Page Project Albums Posts: 2975 Comments: 3 Joined: 11/04/05	does anyone know anything about the Merc Alpha-4 prop?
Tom W Clark	#19  Posted on 10/23/09 - 4:23 PM
Member Personal Page Posts: 4280 Comments: 7 Joined: 09/30/05	Yes, it's cheap crap. The Mercury Alpha 4 looks for all the world like an aluminum version of the VenSura, but here is no comparison in the performance of these two models. The one really excellent application I have found for the VenSura/Offshore is on a classic Bertram 25 with a pair of MerCruiser 3.0 liter sterndrives with regular Alpha 1 drives. This boat was designed in 1961 and back then outboards and sterndrives were designed to run with their AV plates well below the surface of the water. You do not (easily) change the vertical mounting of the sterndrive on your transom. I have a friend with such a boat and when he repowered a few years ago, they put Alpha 4 aluminum four blade propellers on the boat. My friend asked me if I could help improve the performance of his boat so we tested the Alpha 4s for some baseline data. We then tested 17" and 19" Revolution 4s. The 17's were not quite enough pitch, the 19's worked well but did not allow quite enough RPM as well as making the handing a little heavy in turns. We tried the 19" VenSuras and BINGO, the boat handled like a dream and top speed went to 39.4 MPH vs 36.0 MPH for the 18" Alpha 4's and 37.4 MPH and 38.2 MPH for the 19" and 17" Rev 4's, respectively.
kamie	#20  Posted on 10/23/09 - 4:31 PM
Member Personal Page Project Albums Posts: 2975 Comments: 3 Joined: 11/04/05	if you find anyone that needs one, i have a 20p. I got it as part of the deal when I got the 19p Vensura.