Repowering with twin g2 300s

[Skycapt]

Hello again!
The boat in question is a 2007 Jeanneau CC925 Walk Around Sport Fisher, 32 ft (31.8ft), at 5,500 lbs empty weight (usually runs at 8,000 lbs), stepped hull (Michael Peters design) with twin 2007 DF300s (25”, 16X21.5 props, aeration right at the keel). It tops at 65MPH (57knots), goes on plane at 18 MPH (hole shot speed)and falls from the plane at 15 MPH.
I am looking into repowering and I could not ignore the G2s with all the technical innovations and performance they feature plus the looks.
Information based on experience on these engines outside the US is quite limited and I am reverting to this forum for possible expert advice and answers to few questions that I have so to make rather intelligent decisions.
I have been dealing with four strokes through out my boating life and not without problems (engine failures-twice-on water resets and hard resets to erase fault codes, manufacturer mandatory repairs, part recalls etc).
The most frustrating time was during the last engine failure, with good motor “swimming” at WOT and the bad one tilted fully up, the boat was “plowing” the almost calm water at 14 MPH and for a mere 3 to 4 MPH It could not get on the plane so to cover the 32 mile track to the dock in one hour and not in three hours that it took at the end.
As you may understand, the relevant video with the G2 150 and the Yamaha 200 on the same boat with the one planning and the other “plowing” made me SUSPECT that if the day of the failure, the remaining (the good) engine had been a G2 300HP the boat would have cruised at 27MPH to 30MPH.
Is my suspicion correct???

[Skycapt]

In continuation of the previous post I would like to clarify
the following:
The “suspicion” that was expressed was based on few thoughts.
The boat roughly balanced and at rest on the water holds an almost level attitude that is very close to the “step” attitude. When the throttle(s) are placed at WOT, the prop and hence the stern “digs” through the water thus increases the boat attitude and consequently the drag of the hull. At this point, if the engine does not have enough horsepower for the prop to produce adequate thrust to push the boat over the displaced water created “step”, the boat will “plow” the sea for the rest of the day. Therefore, when the stern is at the lowest point (maximum “digging”), the boat is at the maximum attitude (aiming towards the sky), in my case and theoretically speaking, a 300HP motor, no matter the brand, is not enough to “beat” the drag.
So, I am thinking that maybe, just maybe, the extra “kick” of the G2 at the early stages of the RPM and acceleration might make the difference between planning and plowing. Here it is what I mean:
The G2 torque builds faster with an increased margin at lower RPM than the four stroke, higher displacement DF300. The result will be this “kick” that everybody is talking about.
It is very possible that the increased “KICK” (torque) as the engine starts accelerating and building RPM, “pushes” the hull over the step ie hole shot speed is achieved, before the prop and the stern reach the depth they are digging for and the boat reaches its maximum up attitude and therefore, the maximum drag value.
In other words, the early rapidly increasing extra torque to produce an equally increasing horsepower so the resulting thrust at the prop to be always higher than the developing drag producing enough acceleration for the boat to reach the over the step speed (hole shot speed) before the the drag maxed out point where the boat sits on its “bottom”.
Other things being equal, the compelling factor here is the comparison of the torque curves of the G2 300 and the DF300 (is similar to the F300 torque curve).
Again, the boat is a fast swimmer, 31,8’ X 10,3’ with a max power rating of 600HP.

[BluewaterBill]

Your boat has a much better chance of getting up on plane by a single Evinrude E-TEC G2 than with a  4-stroke due to its tremendous low-end  and mid-range torque.

You may want to visit www.etecownersgroup.com as they have a large world wide membership and may have some who are familiar with your boat and its characteristics.

[flsalt]

I'm no tecnical expert on the mater, just a new G2 owner. I repowered a 22 chris craft  walk around cuddy originally 200hp yamaha salt water series 2stroke wot 42mph. The G2  (200HO) just blows it away. No smoke, hole shots incredible and top end 50mph. I run the boat out the inlet drag baits for four hours and back to the dock most days on 5gals of gas my oil consumption is around 60 to 1 I believe. Im at about 110 hrs. I had the screens/water pickups changed to the next larger size as it did over heat after about 50 hrs, fixed the problem.