Boat Lift Center of Gravity ....
#1
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Boat Lift Center of Gravity ....
I am trying to make some adjustments on my lift before we build the roof system this weekend ... Rear beam is about midship of motors ....Front Beam is about 18" ahead of Windshield. It seems the rear is doing more work than the front . I called Formual and they tell me center of Gravity is 8'5" from point where Transom meets the Keel ....Any feed back on where that front beam should be ? Keep in Mind I will not move the bunks but rather move the beam under the bunks to the rear ....I know the rear is going to always bare more weight but I think I can get it closer ....
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Location: Saint Petersburg Fl
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Re: Boat Lift Center of Gravity ....
Mike, Post some more details about the boat and I can tell exactly how much weight is where.
* what does boat weigh
* location of the rear beam
* distance between beams
* length of boat
* what does boat weigh
* location of the rear beam
* distance between beams
* length of boat
#3
Re: Boat Lift Center of Gravity ....
CG is easy to determine. When had a tool to measure the tension on the cables but it's pretty easy to get close just by hand. Our lifts were always double cable, meaning the cable runs from the top to a pully on the beam and back to the top. You could squeeze the two parts together, feeling the tension. Just make the front and the back the same. CG of the boat should be the center of the lift. There is probably 5' from the rear beam to the transom and probably 25' of the bow hanging off my boat.
So it doesn't matter if the beams are 10' apart or 20' apart, the CG of the boat must be in the middle of the two beams.
So it doesn't matter if the beams are 10' apart or 20' apart, the CG of the boat must be in the middle of the two beams.
#4
Re: Boat Lift Center of Gravity ....
When I did my boat lift I called Hustler and they told be the back of the front seat was center of My 388 Hustler. Wrong!!
I back my in and had to use the exesting poles. my front cables are alot tighter than the rear.Its as far back as I can go.I also made it where the fron is higher than the rear , they look funney nose down.
I would do as mr_velocity sound s like a good idear.
Rob
I back my in and had to use the exesting poles. my front cables are alot tighter than the rear.Its as far back as I can go.I also made it where the fron is higher than the rear , they look funney nose down.
I would do as mr_velocity sound s like a good idear.
Rob
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#5
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Re: Boat Lift Center of Gravity ....
311 Formula weighs about 7800 dry ...so I would say 9000 LB
The rear beam is 18" from the Transom
The front Beam is 14'6" from rear beam or 16' from transom
Boat is 31'1" Transom to bow ... 33'1" with platform ....
Formula sez CG is 8'5" from Transom ...
Using velocity's "Formula"
from the CG (101") the rear beam is 83" (18" from Transom)
the front beam is 91" from CG .... So I need to move front beam rearward 8" ...making each beam 83 inches from CG ..
Rear beam would be 18" (existing location..not moved) from transom then 83" to CG ......Then 83" to front beam ( moved 8" to rear) ..... So i am only 8" off ???
Only question in my mind is where should the rear beam be ? I just picked 18" when we set it up .. about mid point of Motors .....
Also the bunks are 20' ...the extend about 4" past transom ..all this moving would not affect the bunks ...Also the front 5' of bunks curve up following the hull ....I tried to make it the same as Eagle trailer Bunks .....
The rear beam is 18" from the Transom
The front Beam is 14'6" from rear beam or 16' from transom
Boat is 31'1" Transom to bow ... 33'1" with platform ....
Formula sez CG is 8'5" from Transom ...
Using velocity's "Formula"
from the CG (101") the rear beam is 83" (18" from Transom)
the front beam is 91" from CG .... So I need to move front beam rearward 8" ...making each beam 83 inches from CG ..
Rear beam would be 18" (existing location..not moved) from transom then 83" to CG ......Then 83" to front beam ( moved 8" to rear) ..... So i am only 8" off ???
Only question in my mind is where should the rear beam be ? I just picked 18" when we set it up .. about mid point of Motors .....
Also the bunks are 20' ...the extend about 4" past transom ..all this moving would not affect the bunks ...Also the front 5' of bunks curve up following the hull ....I tried to make it the same as Eagle trailer Bunks .....
Originally Posted by mneal
Mike, Post some more details about the boat and I can tell exactly how much weight is where.
* what does boat weigh
* location of the rear beam
* distance between beams
* length of boat
* what does boat weigh
* location of the rear beam
* distance between beams
* length of boat
Last edited by offthefront; 03-18-2005 at 09:19 PM.
#6
Re: Boat Lift Center of Gravity ....
I work for Wiggins Lift, we build the marina forklifts for dry stack operations, We have been trying to deal with the OEM's for years on getting thier CG info straight and none of them get it right EVER.
#8
Re: Boat Lift Center of Gravity ....
Placing the rear beams really depends on how massive your bunks are. Since you are using a "boat house" lift you can place the beams anywhere. So I would move the rear beam as close to the transom as you can. The #1 concern when setting up a lift is to suppor the transom as much as possible to avoid hooking the boat. 18" from the transom is the best I have ever seen.
The last 8" probably isn't that big of a deal.
The last 8" probably isn't that big of a deal.
#9
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Re: Boat Lift Center of Gravity ....
I might slide front beam back about 12" .... I still think that because rear beam is 18" from edge of Transom that it bares more than 1/2 the load ... cpl of pics .....