boat house lift question..

[flashback]

I have recently moved my boat to watts bar to a boat house that has a cradle lift. the boat that was in there before was a 19 ft. bass boat that might have weighed 1800 lbs. my boat is a 21 ft scorpion that weighs about 3600 lbs.. the lift motor and gears are rated at 4500 lbs.. this system is very simple, the worm gear turns a much larger gear that is attached to a 2 inch pipe going down the center of the boat house. as the pipe turns, the cables (4 cables one on each corner) go thru a 4 inch sheave and across to the pipe then wind up around the pipe to lift the boat.. the cables are 1/4 inch galvanized steel..most of the weight is on the 2 rear cables with very little on the front cables..since i know the capacity of the gear system is 4500 lbs, and capable of lifting the boat, I need to know if the rest of the system would be as equally as strong... I know you folks can't really make an accurate reccommendation, but any experience would really help. thanks Flash

 

[mattttt25]

Re: boat house lift question..

gauge of pipe and diameter of steel cables?

 

[flashback]

Re: boat house lift question..

Hi Matt, the pipe is 3/16 inch thick and the cable is 1/4 galvanized steel.. the 4 upright posts are 4 inch steel 1/4 thick and the framework is 3 inch steel 3/16 inch thick. the 4 sheaves at each corner are 4 inches in diameter with a 5/16 inch axle pin.. there is also some 2 inch steel that is welded across the frame that has a bushing welded to it that the pipe rides in. these cross members are placed near the area of pipe that the wire spools on..I don't have a digital camera or I could post a pic.. but I hope this makes it a little more clear.. thanks

 

[Bob_VT]

Re: boat house lift question..

Technically a single piece of 1/4" steel cable will do the trick (usually about 6500 lb breaking strength and you should only use up to the 70% mark). Four cables and what you described sounds good. I'm no pro on it but I have worked with cable and wire rope.

 

[flashback]

Re: boat house lift question..

Hi bob, thanks for the info, I guess from what you say the cable is good, I have picked up the boat with it, and it works, I guess my concern is will the rest of the system be adequate. I do need to re-work the cradle so it fits my boat. That being said, the two stern cables carry a lot more than the 2 bow cables. but for it to wind evenly, they all need to be the same size..