2003 Dauntless 220 Re-power with Mercury 225 ProXS

[Gluis]

I re-powered my 2003 220 DAUNTLESS with a Mercury 225-HP ProXS engine. I want to get:

• the best acceleration,
• the best fuel economy at mid-throttle,
• the best acceleration at full-throttle from a standing start, and
• the best full throttle boat speed.

The initial set-up was the engine mounted at lowest possible position.

Propeller = ENERTIA 19 pitch
RPM = barely accelerated to 5,550 which was below the [suggested optimum] engine speed
MPH = 50 (easily)
MPG = Terrible

The next change was to raise the engine to be mounted two-holes-up as Boston Whaler recommended.

Propeller = ENERTIA 19 pitch
RPM = 5,950
MPH = 50

Next test was a new propeller
Propeller = [ENERTIA] ECO 17-pitch
RPM = 5,800
MPH = 49

The tests were done on different days. There might have been a marginal improvement had the [ENERTIA] ECO been tested on the same day [as the ENERTIA was tested].

Next change was to raise the engine up two-holes more and re-test [Apparently engine is now mounted four-holes-up]

Propeller = ENERTIA 19 pitch
RPM = [added] 350
Propeller ventilated and lost grip; acceleration at full-throttle from standing start improved, top speed improved, fuel economy improved.


Propeller = [ENERTIA] ECO 17-pitch
Acceleration at full-throttle from a standing start improved slightly
MPG = improved
MPH = decreased slightly
Calculated value of SLIP was lower.


Overall the biggest differences I found:

• I had to really work for that 49-MPH [top boat speed reading] with the [ENERTIA] ECO [17-pitch]
• [with the ENERTIA 19-pitch] the 50-MPH [top boat speed] came easily.

The [ENERTIA] ECO 17 has bow lift. Bow lift is a big positive for me; I spend time maneuvering large swells and rough seas in the Pacific Northwest. The boat could make a U-turn at 40-MPH without loss of grip. At slow speed dock maneuvers the [ENERTIA] ECO 17 was better than the ENERTIA 19.

Next propeller to test will be a MIRAGEplus The diameter of the MIRAGEplus will be midway [between the diameters of the ENERTIA 19 and the [ENERTIA] ECO 17.]

Then I will test a. REVOLUTION4 17 pitch.

ASIDE
This forum has provided me a wealth of knowledge over the years. I hope some of my personal experience [may] help someone else.

[fno]

I would not be surprised to see the MIRAGEplus give you the best overall performance. The REVOLUTION4 will be a step down if speed is your need.

[jimh]

As I recall, the ENERTIA ECO propeller was developed by Mercury Marine in response to owners of the Mercury Marine VERADO supercharged engines and a request for improved fuel economy. The design of the ENERTIA ECO was presumably developed more or less specifically for use on the VERADO engines of 250-HP to 300-HP. The objective was to maintain the performance of the ENERTIA while simultaneously improving fuel economy.

Test results which tended to show significant improvement by changing to the ENERTIA ECO often used the REVOLUTION4 propeller as the benchmark. However, as often noted, there were already other propellers, such as a MIRAGEplus three-bladed propeller, that could also exhibit significantly better fuel economy than a REVOLUTION4.

Threads discussing the ENERTIA ECO at the time of its introduction add further comments. See the old forum archives at

Mercury MIRACLE Propeller
https://continuouswave.com/ubb/Forum4/HTML/008144.html

ENERTIA ECO Propeller Announced
https://continuouswave.com/ubb/Forum4/HTML/007946.html

Another problem with the ENERTIA ECO is its diameter: 16-inches. This may be too large for many outboard engine propeller apertures to allow use.

Also from the old forum archives is an outstanding thread in which the MIRAGEplus is compared to the ENERTIA propeller.

ENERTIA v. MIRAGE
https://continuouswave.com/ubb/Forum4/HTML/006785.html