I am interested in the top speed of the 22 Whaler Drive with 300-HP. I also have a 22 Whaler Drive, but with 225-HP. My boat is not an OUTRAGE but a REVENGE, so the original hull weights are not the same; the REVENGE is heavier by 300-lbs. The OUTRAGE in this situation has a T-Top and twin engines, both adding extra weight. It is likely the OUTRAGE 22 Whaler Drive with twin engines weighs as least as much as my REVENGE 22 W-T Whaler Drive, and perhaps may be even heavier.
In many tests with many propellers, the top speed of my 22 Whaler Drive boat with 225-HP is between 41 and 44-MPH. Let's use a figure of 42.5-MPH as a reliable top speed.
The increase in speed that would be anticipated if the engine power were increased to 300 from 225-HP (while the total weight remains the same) is proportional to the the power ratio to the 0.5 exponent. Thus the estimated top speed for such a power increase would be:
MPH = 42.5 × (300/225)0.5
MPH = 49
The reported top speed at 47-MPH is slightly less than expected, but this is probably due to three factors tending to reduce speed:
- the additional drag of two gear cases with the twin engine rigging
- the additional air resistance of the T-Top
- weight variations between the two boats
The engine weight differs by about 300-lbs, that is, about 500-lbs for a single engine and about 800-lbs for twin engines. The hull weight favors the lighter OUTRAGE by 300-lbs. The two boats should have similar weights The addition of the T-Top might bring the hull weigh of the OUTRAGE to be greater. Certainly the air resistance of the T-Top has an influence.
Let's repeat the speed estimate calculation, but allow for the OUTRAGE 22 Whaler Drive boat with twins to be five-percent heavier, based on a difference of say 150-lbs in boats that weight about 4,300-lbs The math looks like this
MPH = 42.5 × (0.95 ×(300/225))0.5
MPH = 47.8
Now the predicted speed is very close to the reported speed.
I have given some (idle) thought to re-fitting my boat with twin E-TEC 140-HP engines. When I look at my pattern of use of my boat the last five years, I cannot justify investing in new engines. But I do find speculating and analyzing the possibilities to be fun.
I think the twin 150-HP E-TEC three-cylinder G2 engines are a great choice for fitting twins on a 22 Whaler Drive boat. As remarked above, at almost 800-lbs the two engines are probably close to presumed maximum weight for a Whaler Drive boat. I would be particularly conservative about total engine weight on a Whaler Drive boat when the boat is NOT in the water. With a Whaler Drive boat on a trailer, the drive is supporting all the engine weight without the benefit of the buoyancy force the Whaler Drive creates in the water.