papajoe74
Well-Known Member
I ordered a 24LSB with a 200 Yamaha. I just put in a vertical lift and am trying to figure out where the best balance point will be. I know it will be toward the back.any body have an idea how to figure it out?
Center of gravity
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CLDave
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It's going to be different for every boat, but it's relatively easy to do this on the lift by getting it as close as you can, and then raising the boat up just a bit so the cables are starting to lift - and then checking the tension of the cables to feel if they're uniform. You can tell by "wiggling" the cable how much stress is on them.
You'll be farther forward than you think.
You'll be farther forward than you think.
Timdelta
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I talked to a senior engineer at the company and he shared the following info, concerning my QFB 25. His reply is in the quotation marks below.
My lift guy said it’s always around the helm area on all boats, so that may be a good starting point.
“Tim,
Try testing to the above example.
A good general number is 35% of the length of the outboard tubes. Measure the outer tube in feet, not marketing boat names. CG is within 5% plus or minus. (25 R, Single example 25'-4" x .35= 8.9 feet forward of the endcap) (Twin 27 models, 27'-0" x .35= 9.5 feet forward of the transom)
For lifts, boat CG may not be enough to base support on. A big live load on the bow of the boat will throw the CG way off.
For splitting hairs.....
10' single is closer to 40%
Twins are closer to 30%
Small boats are found at both extremes.
To know exactly, set up the boat with specific engine(s) fuel batteries and whatever else people and load wise. Weight the four corners with race car scales and crunch the numbers.
Strong points are at the tube section welds.
When not supported well there, check to make sure there is no deflection on the tube when bunks are lifting the boat & boat with live load.
Lifts that use stringers to support the deck (no tube bunks) can be as short as 55% boat length if live load is kept at a minimum.
Xxxxxxof Product Engineering”
Sent from my iPhone
My lift guy said it’s always around the helm area on all boats, so that may be a good starting point.
“Tim,
Try testing to the above example.
A good general number is 35% of the length of the outboard tubes. Measure the outer tube in feet, not marketing boat names. CG is within 5% plus or minus. (25 R, Single example 25'-4" x .35= 8.9 feet forward of the endcap) (Twin 27 models, 27'-0" x .35= 9.5 feet forward of the transom)
For lifts, boat CG may not be enough to base support on. A big live load on the bow of the boat will throw the CG way off.
For splitting hairs.....
10' single is closer to 40%
Twins are closer to 30%
Small boats are found at both extremes.
To know exactly, set up the boat with specific engine(s) fuel batteries and whatever else people and load wise. Weight the four corners with race car scales and crunch the numbers.
Strong points are at the tube section welds.
When not supported well there, check to make sure there is no deflection on the tube when bunks are lifting the boat & boat with live load.
Lifts that use stringers to support the deck (no tube bunks) can be as short as 55% boat length if live load is kept at a minimum.
Xxxxxxof Product Engineering”
Sent from my iPhone
papajoe74
Well-Known Member
Thanks Timdelta and CLDave. very good info.