Compensating for Added Engine Weight

[BassettBW]

If I move battery to the center console from the transom, will it compensate for increased engine weight on the transom?

ASIDE: My 1989 Montauk [ALWAYS MENTION THE TWO DIGIT OR THREE DIGIT LENGTH DESIGNATOR WHEN DESCRIBING A PARTICULAR BOSTON WHALER MODEL] has a Johnson 110-HP engine that is said to a dry weigh of 300-lbs. A Mercury 90-HP FOURSTROKE engine has a dry weight of 359-lbs.

[Jefecinco]

Moving the battery forward will not change the weight. It can change the center of gravity.

[BassettBW]

Q1: does [an increase in the engine weight of] 60- to 70-lbs make much difference when considering a repower?

I know this has been discussed here for years but seems like every year the modern engines get lighter. I am asking:

Q2: does [an increase in engine weight by 70-lbs] really matter?

[Phil T]

You are correct. Moving the battery to the center console (cut the shelf so it rests on the deck) will ofset the added weight in the stern.

The boat can handle the added weight.

[jimh]

If I move battery to the center console from the transom, will it compensate for increased engine weight on the transom?

Moving weight to amidships will affect the static and dynamic trim on the boat. The increased engine weight remains as a negative influence on performance. If you want to compensate for increased engine weight, you must remove weight elsewhere in the boat.

All weight added affects performance.

You are welcome to talk yourself into believing that you can add weight without any effect on the boat performance.

Q2: does [an increase in engine weight by 70-lbs] really matter?

The effect adding of 70-lbs depends on the total boat weight. If a boat already weighs 7,000-lbs, then an increase of 70-lbs will likely not be noticed. If a boat weighs 700-lbs, adding 70-lbs will be noticeable.

You can also consider that 70-lbs is about 12-gallons of gasoline fuel. If the fuel tank volume capacity is 12-gallons or more, the boat weight would tend to vary by about 70-lbs as the fuel in the fuel tank was consumed by the engine.