My 2006 Carver 44 CMY is equipped with Volvo Penta D6-370 HP diesel engines and I wanted to find out what if any impact the weight of my 530 Lb Highfield dinghy and full aux. tanks had on the performance of my boat. Don't forget the YETI full of beer.

I was on a trip this summer up to the North Channel for two weeks and had an opportunity to run her on plane a fair amount. I left Killarney with full saddle and aux. tanks and my dinghy on the swim platform down to Parry Sound in open water. I ran her for 4 1/2 hours at 90% of WOT as recommended in the manual (3240 RPM's). I was running at 19.5 MPH, which I thought was a little low. In discussions with my fellow boaters I began to question whether or not my Turbo's were boosting up enough. In addition I also wondered if the weight of the dinghy and the fuel was impairing the performance of my boat. Still, 19.5 miles per hour on a 34,000 Lb +- boats is not bad.

This weekend I took the boat out with the Admiral and left the dinghy at the dock to see how the boat performed without it and to get some turbo readings from the EVC displays on the helm. I had 5/8's of fuel in my saddle tanks and about 3/8's fuel in my aux. tanks.

Here is the data from the exercise;

RPM's, Boost Port (psi), Boost Stbd (psi), IGPH, Speed (MPH)
1000, 0.3, 0.0, ?, 6,
1500, 1.2, 0.9, 3.43, 8.3,
2000, 4.1, 3.8, 8.05, 10.2,
2500, 12, 11, 14.4, 12.2,
3000, 21, 20, 21.5, 17.6,
3200, 23, 23, 25.4, 20.3,
3240, 24, 24, 26.2, 21.2, 90% of WOT
3600, 29, 30 (3630), ?, 26.2, WOT
(It appears that the structure of the chart looses spacing when submitted)

For the purpose of this exercise I used Canadian Gallons(IGPH) and Miles Per Hour(MPH)

As you can see I was able to achieve 3600 RPM's on the Port engine and 3630 RPM's on the Starboard engine at WOT. I did not capture the fuel burn at WOT, just forgot to I guess. When loaded up it can be a challenge to achieve 3600 RPM's at WOT with all the weight on the aft end.

I have to research the boost levels I achieved to see if they are within an acceptable range, but both engines were comparable except they were a bit off at the lower RPM's. From what I have read so far the levels seem within an acceptable range. It is also very clear to me that the weight of fuel and the dinghy does impact the speed that I am able to achieve while on plane. However, I only lost 1.7 MPH with full fuel and the dinghy, compared to the fuel on board at the time of the exercise.

When I purchased the boat in 2017I was able to attain 3600 RPM's at WOT and was traveling at 29.5 MPH. I was also able to attain approx. 23 MPH at 3200 RPM's at this time. At sea trial the water tanks were bone dry, fuel in the saddle tanks were just south of 1/2, the aux were about 1/4 full and no dinghy.

It is clear that fuel and the weight of the dinghy play a big roll in the speed and performance of this boat on plane. However, I believe it is within an acceptable range when on a long haul trip. It is worth the speed drop to have the luxury of the dinghy on board. When I purchased the dinghy I had the chord on my trim tabs extended 2" to compensate for the additional weight on the aft. I do believe that this assists in lifting the aft up and out of the water more.

I also believe that a big factor is the weight of the cockpit, swim platform and the aux tanks aft of the props which are situated in front of the transom. There is a lot hanging off the back of this boat.

I hope the results of this exercise assist some of you with any questions about performance of your 44 CMY and/or your Volvo D6-370 HP diesel engines.

I welcome questions and comments, as this is what this forum is all about.

Greg