Rev 4 to Enertia

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B-Faithful

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Today I finally put an Enertia 17 on my boat. I had been running a 17" Rev 4 which I absolutely loved but didn't like the fact that my max rmps had me in the low 5000's (5100-5300 depending upon load, etc.). The 225 Opti manual states a max operating range of 5000-5750 and recommends being in the top half of that. I feared extended use of the 17" Rev 4 would hurt the longevity of my motor. I had also earlier purchased a Rev 4 15" that was way too small of wheel. I burned no fuel and went no where with the prop . It was definitely the wrong prop.

Being that Merc had hyped the Enertia prop as able to plane at lower speeds, higher rpms due to thinner blades, faster top end, etc, I wanted to give one a go so I bought one. Anyhow, without official graphics to show my speed, fuel burn, etc. I thought I would post my thoughts and views of the two props. Keep in mind this is my inital experience with the Enertia as I just took a short ride with the prop earlier today. The conditions were not ideal as it was blowing 20-25knots out of the north. However, i ran some in a protected creek and put my nose out into the bay for a bit.

1. Around the docks -- Rev 4 bites a lot better. As soon as I would hit the boat in gear the prop would start biting. The Enertia is not bad, it just requires a little more juice to maneuver the boat.

2. getting on plane -- I don't want to call it hole-shot as I am not a "gun it" type guy. This is hard to say. Both props put the boat on plane adequately and I couldn't really tell if one would put it on plane more quickly or not

3. maintaining plane at slower speeds -- much to my surprise, the Enertia was able to hold a slower speed on plane than the 4 blade prop despite its smaller diameter. The Rev 4 would bog and ventilate if I dropped the speed too low between plowing and barely on plane. With the enertia I could go from plowing to planing and back again slowly without ventilation.

4. Ventilation -- While the Enertia allowed me to drop my speed slower, the Rev 4 wins this one hands down. I could trim the motor WAY up with the Rev 4 and it wouldn't lose bite. I also could go through some moderate turns with the engine way up and it wouldn't lose bite. The Enertia was A LOT better than the Mirage and Black Max I had run in the past but running through a narrow channel with windy turns I had to tuck the motor in some more to keep the bite. I also couldn't raise the motor near the height that I did the rev 4 without losing bite. I don't believe ventilation will be an issue with the Enertia, i just have to keep the motor trimmed down more than the Rev 4.

5. Cruising -- this is the meat and potatoes for me as I rarely run WOT (just do to gauge prop load on engine). To me this is a tough call and will require more time running. I generally cruise the boat right at 4000rpms. In the protected creek where I keep the boat the Rev 4 would go 28-29mph with a regular load burning just over 10gph. However that would push quickly to 11gph in a chop to maintain the same rpm. In the creek, the Enertia had me at 27-28 mph depending on what direction I was running at 4000rpms but I was burning just on the low 9gph's. Today I had over 100gal of fuel regular gear (minus fishing gear) and two of us on board. When we ran out to the moderately choppy bay today, the boat ran 26-27 into the head sea still burning under 10gph. The lower fuel burn at a given rpm shows that the engine is under less load. Something I am happy about.

6. trim/run angle -- As far as trim goes, the Rev 4 wins hands down. I can really notice the bow come up with the raising of the engine and feel it go down with tucking in. However, I believe that the boat may have a more "natural" run angle with the Enertia. This is tough to explain but I believe every boat has a natural run angle and it takes learning the boat and its trim to find that. I felt that while I couldn't feel the affects of the motor trim with Enertia compared to the rev 4 that it was more where the hull wanted to run despite the trim. I don't meant to make it sound like the trim of the motor had very little affect on the run angle of the boat but it did in comparison to the very "bitey" Rev 4.

7. WOT -- This is an odd one and I believe it has a lot to do with the style hull I run. With the Rev 4 I would hit 40-41 easily at 5100-5250. I have even hit 42 mph when I had her trimmed perfectly. With the Enertia, I was hitting over 5500 (I think around 5580 not blowing out) and running 39 point something. I couldn't get the gps to hit 40mph even though I had it at 39.8 on a couple of shots. I am not sure if it has a lot to do with the wind but I was in a protected creek where I ran about the same speed in both directions on several runs. I believe a lot has to do with the hull and the ability to raise bow up more with the rev 4. My hull has a very deep v entry with a very shallow transom (10-12degrees of deadrise). The ability to really raise the bow with the rev 4 I believe enabled me to gain a few extra MPH. When doing this, the boat would porpoise some. With the Enertia, I couldn't raise the motor as high and the boat felt as if it was running more level creating more surface area in the water. The boat wasnt porpoising at all where I had the enteria trimmed.

I didnt really listen for "clunking" when going in and out of gear to comment on that and didnt think that the blades of the looked thinner than the rev 4. It did feel noticably lighter. Howeve the diameter of the Enteria is less and it is also a blade less than the Rev 4. The Enertia does appear to have good blade surface for a 3 blader though.

Again, these are just my initial reactions to runnig the prop for 20-30 minutes tonight (Was rushed to get home for dinner if that says anything)..... Nothing scientific or set in stone as far as my experience or opinions go as I need more time on the water with it.
 
Thanks for the info.

My boat is alittle heavier and bigger but the info really helps out.

1.)Are you going to switch to the Enertia or stick with the Rev4?

2.)How different are the numbers between Mirage Plus and Enertia?


3.) Also can you give me the WOT rpm/mph for all of the props you tired for a good comparision?

Mirage Plus 17pitch RPM MPH
Rev 4 17 pitch
Enertia 17 pitch
Any other prop you tried

I think that would give a good picture to see at once.


I am currently swinging a 15pitch Mirage Plus and getting 5350rpm out of my tired Optimax 225hp. I have been thinking about switching over to a 15pitch REV 4 for more stern lift or maybe a 15pitch Enertia for more RPM. I can stay on plane at 3000rpm after I added dolfins to the cav plate (20mph). At WOT 5350, I am just a shade under 40mph.

Thanks
bertamcan2.jpg
 
Definitely stick with the prop that gets you 200-to-no-more-than-300 RPMs off maximum WOT.

To do otherwise, will surely hasten the demise of your motor.
 
I do not think you researched those props enough! :lol:
 
My boat is alittle heavier and bigger but the info really helps out.

1.)Are you going to switch to the Enertia or stick with the Rev4?
Enertia, less load on the motor. Motor longevity trumps performance in my book. Also there are areas in which the Enertia performs better

2.)How different are the numbers between Mirage Plus and Enertia?
I cannot remember, I ran it long ago but dont remember much difference from the AL black max I had been running at the time. The prop ventilated if not trimmed down in a chop. The Enertia was made to take the place of the Mirage plus. Despite its smaller diameter it supposively has more blade surface area than the mirage plus. See article here:
http://www.boatingmag.com/article.asp?s ... rint_page=
y


3.) Also can you give me the WOT rpm/mph for all of the props you tired for a good comparision?
You are relying on bad memory and varying sea conditions... The only props I have run regularly were a 17" black max and Rev 4 17" and only tested the others shortly

Mirage Plus 17pitch-right under 40mph but blowing out at around 5400
Rev 4 17 pitch -- 5100-5300 ~41-42mph
Enertia 17 pitch -- 5580 ~40 mph
Any other prop you tried
17" black max ~38mph blowing out at 5700
I also tried a 19" black max but dont recall -- too much pitch


I think that would give a good picture to see at once.


I am currently swinging a 15pitch Mirage Plus and getting 5350rpm out of my tired Optimax 225hp. I have been thinking about switching over to a 15pitch REV 4 for more stern lift or maybe a 15pitch Enertia for more RPM. I can stay on plane at 3000rpm after I added dolfins to the cav plate (20mph). At WOT 5350, I am just a shade under 40mph.

I would guess and probably try the 15 Re4 first for your boat. It that doesnt work out I may try a 16" Enertia (Enertia comes in all pitches)


Keep in mind, i am purely guessing and probably shouldnt. However I cannot help myself because it is fun. (it is amazing how much difference a prop can make in the way a boat runs-- too bad it is soo $$ to test without someone like propgods.com around me :shock: )

The prop I would like to test next is the Tempest 17" but I am not going to do it..
 
I'm currently swinging a 17p Mirage plus, but my 225 OX66 will only run to 5000 rpm with this prop (not that I get the chance to run WOT very often). Other than the lack of WOT rpm's, this prop gives me great performance around the dock and at cruise speeds.

The Enertia sounds interesting and I'm thinking that a 16x16 might get me closer to 5500 at WOT, but I'm a bit leery about loosing the low speed and mid-range performance I'm enjoying now.

Since I rarely ever see WOT, I wonder if I should even care about a few hundred rpms on the top end.
 
I don't run WOT either. However it gives a good indication of load on the motor through the rpm band. If a boat cannot turn a prop the recommended rpms at wot, most likely the load on motor at cruisee is higher than recommended too. If the load is too great, it can cause excessive carbon build up and increased combustion chamber temps. Both shorten the life of the motor.

The example of this is looking at my cruise of 4000rpms. With the rev 4 I burn between 10 and 11gph swinging that prop at 4000 rpms and can only muster in the low 5000's at wot. With the enertia I am burning a full gph less at 4000 but can turn over 5500. While a gph may not sound like much, it is still at least 10% less at the given rpm. While I ran faster at that given rpm with th rev4, I can see there is less load on the motor with the enertia. In other words buy being able to hit the recommended rpms at wot I am more comfortable with the strain on the motor throughout the rpm band.

Just my school of thought.
 
Did you raise the motor after installing the Rev 4? If not, I'm not sure you're gettin all the performance out of it.
 
I am very much on the high side if anything. The Opti just sports a 1.75;1 gear ratio vs the yam 4 stroke 2.0:1. That is probably the main reason for not being able to "optimally" turn the 17" rev 4.
 
Hi B Man,

Good to hear your getting closer to the 6K on the yamaha.

Not sure if you sold the Rev 4 yet - I'd still like to take it off your hands.

Cheers,
wp.
 
Wicho, I tenatively have it sold to a local guy who is going to give me cash for it. However, he hasnt responded to my last few emails so I have a list of others who wanted it. If I dont hear from the local guy in the next few days, I will let you know.
 
I ran the boat some more today. The more I run the boat, The more I like the prop. It was a calm day but I was able to run ~4150 at 28.3mph burning 10.3gph. If I slowed to 3950 She burned 9.0gph running around 26.8-27mph. Running at 4400rpms had her running over 31mph at 11.8gph. WOT she ran 41mph at 5500 burning 20.8-21gph. The prop still requires a little more juice around the docks to get her to move but I can bog the boat without losing bite. It also really jumps on plane with this prop. Despite the 14.5" diameter, the prop really has a lot of blade surface for a 3 blader. I do keep the motor tucked down to ~5.5 on the trim guage vs the 6.5 I used to run with the rev 4.

Of course I wrote nothing down when I was out there so this is purely based on my poor memory :lol:
 
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