By Thomas P.

Facing one of the best well-designed ribs which is indeed characterized by its fast hull, and two of the best-designed propellers it was impossible to resist the temptation.
We tested the Hydromotive 15 ½" x 19" (lab finished) and the Eco Enertia 16" x 17" in a Technohull SEADNA 999 on the transom of which a Verado 350hp was mounted.

Hydromotive vs Eco Enertia

The purpose of this test was not, of course, the comparison of the two propellers, which have absolutely nothing in common between them.

We just wanted to see the behavior of the above combination rib - engine when it is working with two such different propellers.

We should note that the tests took place with the rib loaded with 400 litters of fuel and a crew of three persons.

Τest results

Hydromotive vs Eco Enertia

Observations

Looking at the table above we can easily see that:

  • Hydromotive gave us higher planning speed
  • Hydromotive gave us higher speeds over the whole speed range, even with the same fuel consumption. However Eco Enertia gave us higher final speed because it turns 400 rpm more than Hydromotive at WOT
  • Both propellers showed approximately the same slip numbers, which were remarkably high
  • Eco Enertia gave us faster accelerations
  • The throttle response, which is not particularly noticeable, is about the same for both propellers
  • The slow accelerations and the high slip numbers show us that the rib moves marginally with 350 hp on its transom. The low speeds we observed until 4000 rpm with both propellers also show that. However, the exceptional final speeds which we recorded with both propellers are noteworthy.

Below we provide detailed measurements of both propellers

Hydromotive 15 1/2” x 19”pdf

 

Eco Enertia 16” x 17”pdf

 

It is really worth trying a 19" pitch Eco Enertia in the above combination boat-engine, which will allow the engine to spin up to 6000 rpm with the specific loads. Then indeed we will be able to get more useful comparative conclusions.

When of course we run with fewer loads, then the 19" pitch Eco Enertia will allow the engine to reach 6400 rpm, giving us even higher top speed.

Hydromotive vs Eco Enertia

...keep Ribbing!