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View Full Version : Gas Mileage and Trim plates


vision
10-10-2007, 08:56 AM
Anyone have trim tabs on an X Star and does it improve your gas mileage? I realize that you do not want the tabs in action while boarding. But for the 30% of the time that we are not boarding but just cruising, would trim plates significantly alter fuel efficiency by getting the boat to plane faster?

Maristar210
10-10-2007, 09:36 AM
I would not think theere would be much of a difference in mileage.

Jesus_Freak
10-10-2007, 11:46 PM
The lifting force required to move the rear of the boat vertically upwards does not come for free, even if the trim system is hydrodynamically well-designed. Fuel will be consumed to apply this force, just as in jet fuel is consumed to lift an aircraft. Maybe the net result is indeed better mileage. Interesting thought...Anyone?

MYMC
10-11-2007, 10:37 AM
The lifting force required to move the rear of the boat vertically upwards does not come for free, even if the trim system is hydrodynamically well-designed. Fuel will be consumed to apply this force, just as in jet fuel is consumed to lift an aircraft. Maybe the net result is indeed better mileage. Interesting thought...Anyone?
I guess I didnt realize X-Stars had a problem getting to plane.

G-man
10-11-2007, 10:45 AM
If you want gas milage don't use ballast. Gas is just one of those given expenses it takes to play

Leroy
10-11-2007, 11:46 AM
I can't imagine this changing gas mileage positive. I think some of the fundamentals to mileage are: boat weight, surface area in contact with water, drag (how smooth is the hull), your driving style (looks at GPH vs speed table), engine HP, etc If anything the tab just creates more drag.

MYMC
10-11-2007, 12:12 PM
I can't imagine this changing gas mileage positive. I think some of the fundamentals to mileage are: boat weight, surface area in contact with water, drag (how smooth is the hull), your driving style (looks at GPH vs speed table), engine HP, etc If anything the tab just creates more drag.
Well said...

Jesus_Freak
10-12-2007, 04:25 AM
...If anything the tab just creates more drag.

If the boat rides differently with some device installed, that changes the shape/depth (possibly reduces the area) of the part of the hull surface in contact with the water. Because of this I didnt think the answer was obvious. I dont know jack about this hull or trim tabs; I was only commenting from a general technical standpoint.

Leroy
10-12-2007, 08:23 AM
Jesus Freak; I'm definitely not a fluid dynamics engineer, but I practice in the evening......I guess the easier answer is if it improved gas mileage MYMC, BAWs and every other dealer and Mastercraft would have already let us know! :)

vision
10-12-2007, 02:32 PM
I will see if I can find the reference. But on certain cruise ships they use trim plates to to improve gas mileage over the long haul. The question is whether there would be a practical difference on short trips on a small (but heavily weighted) boat. You expend energy to displace water with the plates, but you reduce overall friction with the water over time by changing the position of the boat which is where the fuel economy occurs.

Jesus_Freak
10-17-2007, 06:06 AM
...I guess the easier answer is if it improved gas mileage MYMC, BAWs and every other dealer and Mastercraft would have already let us know! :)

Agreed. We would normally think this. Just a few months ago, however, MYMC and I discovered an "issue" related to performance that even Mastercraft didnt know. Nobody is perfect, right?

Leroy
10-17-2007, 07:46 AM
I would say some people are exceptional!

Agreed. We would normally think this. Just a few months ago, however, MYMC and I discovered an "issue" related to performance that even Mastercraft didnt know. Nobody is perfect, right?