1997 Outrage 20 with 175 HP ETEC; Seven Propellers

Optimizing the performance of Boston Whaler boats
jcush87
Posts: 20
Joined: Sun Nov 08, 2015 7:19 pm

1997 Outrage 20 with 175 HP ETEC; Seven Propellers

Postby jcush87 » Fri Aug 28, 2020 12:27 pm

When I re-powered my [1997 OUTRAGE 20] boat in 2011 [with an E-TEC 175-HP engine], I went through quite a few propellers to obtain the optimum performance characteristics. I think some of this information may have been on the old forum, but I thought posting this performance data here may end up helping someone.

My criteria were:
  • reaching optimum RPM for my ETEC - 5500-5700 RPM
  • Handling at cruise, at low speed, at reverse, ability to hold the bow properly
  • MPG
  • WOT speed

I happily settled on the Mercury ENERTIA 15--it has been excellent all-round propeler. I liked the BRP REBEL as well but [the E-TEC 175 engine] didn't reach optimum RPM. I kept the Mercury MIRAGEplus 15 as a backup. The BRP SST performed well also. The BRP VIPER propellers did not feel very good, and had a significant lack of reverse thrust.

The boat was lightly loaded, roughly 1/3-FULL tank of fuel, 400-lbs crew, maybe another 350-lbs of equipment counting batteries oil tank.

Data was averaged up-current/upwind and down-current/doenwind.

Temperature was in the upper 80's, water was saltwater, waves were less than 6-inches.

Bimini top was down.

Engine mounting was all the way up.

Viper 19 test data may have been recorded at two-holes-up.

No fin added on gear case. Trim tabs retracted

1997 Outrage 20 E-TEC 175

ENERTIA 15			
RPM MPH MPG % Slip
3500 23.8 3.8 12
4000 29.9 3.7 3
5675 42.7 2.6 2

REBEL 15
3400 25.8 3.9 1
4000 31.0 3.6 -1

MIRAGEplus 15
3200 23.5 3.6 4
4000 30.0 3.5 2
5350 38.0 7
5325 40.8 2.6 0

MIRAGEplus 17
3800 29.0 3.6 7
5200 41.0 4

OMC SST 17
3600 27.6 3.8 12
4000 29.9 3.6 14
5500 44.1 8

VIPER 16
3500 21.5 3.6 25
4000 28.3 3.6 14
5500 41.0 2.6 9

VIPER 19
3600 29.9 4.1 15
4000 33.0 3.6 15
4900 42.0 2.6 12

User avatar
Phil T
Posts: 2602
Joined: Thu Oct 22, 2015 6:08 pm
Location: Was Maine. Temporarily Kentucky

Re: 1997 Outrage 20 with 175 HP ETEC; Seven Propellers

Postby Phil T » Fri Aug 28, 2020 1:09 pm

Why not select the SST 17"? What were the characteristics that eliminated it given it provided the best WOT speed by a measureable amount?
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
Posts: 11670
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: 1997 Outrage 20 with 175 HP ETEC; Seven Propellers

Postby jimh » Fri Aug 28, 2020 1:32 pm

I would like to try an ENERTIA propeller, but I don't want to buy one to test it--they are at a premium price point.

I have tried a REBEL 17 and a MIRAGEplus 17 on my E-TEC, a 225-HP, and I found the outcomes were identical, with the REBEL giving a slight edge in fuel economy.

Thanks for posting the test data. To see information like this is always useful and interesting.

jcush87
Posts: 20
Joined: Sun Nov 08, 2015 7:19 pm

Re: 1997 Outrage 20 with 175 HP ETEC; Seven Propellers

Postby jcush87 » Mon Aug 31, 2020 7:54 am

Phil T, fair question! The SST 17 I tried was borrowed from someone and while it performed very well, I decided to keep looking.
The SST 17 wasn't available new, so anything I bought had the risk of being damaged (there were non is saw that were "like new" either)
With a fairly light load, it just touched the beginning of the optimum RPM range. I knew with a full diving or fishing load it wouldn't be quite there. Also the SST was a pressed hub design rather than the user serviceable modern design with a hub kit.

In the end the Enertia provided more positive control, less prone to ventilation in turns, and if i recall correctly slightly better hole shot. The only downside I have seen to the Enertia propeller is that it is so massive (no matter what Mercury wants you to believe) is that sometimes coasting down in speed while in forward and quickly putting it in reverse can actually stall the engine. Once this was known, I was able to adapt my driving style by pausing for about a second between forward and reverse. I'm also confident that in an emergency where I needed to switch to reverse and provide instant throttle input it would manage this fine as well.

I also noticed I had some data misplaced above. should read:
REBEL 15
3400 25.8 3.9 1
4000 31.0 3.6 -1
5325 40.8 2.6 0

MIRAGEplus 15
3200 23.5 3.6 4
4000 30.0 3.5 2
5350 38.0 7