Weigh in (Pic)

[Bill Perkins]

Here’s one for those who like workshop lash ups .

http://www.imagestation.com/picture/sraid148/pe355acd6af104615e77750a71b0959a5/f60f0c5a.jpg

The heart of my system was a spring scale made by the Hanson Co. of Shubuta , Mississippi . It can register up to 200 lb. and is called , for some reason , “The Viking “ . The Viking’s got hold of the fall from my inverted luff tackle , gaining a 4 to 1 advantage on the tackle’s lower hook .This is hooked to the cable of a come along , the runner block at it’s lifting hook giving an advantage of 2 on the doubled sling , for a total advantage of 8 back at the Viking‘s end . " Not for legal trade ."

The setup was convenient in that I could get things quite tight with the tackle before making fast to the hook of the scale . I then stepped off the boat and lifted it with the come along ( a pipe cheater over the handle allowed me to stay out of harms way) .Allowing for some friction at the sheaves I came up with an estimated lift of from 1000 to 1200 lb. This didn’t lift the whole boat , but I was able to deduce a total estimate that I’m comfortable using as a guide when I shop for a trailer . I’ll get an accurate direct reading when I finish and get the boat on her trailer .

[ 12-01-2004, 06:21 PM: Message edited by: Bill Perkins ]

[PaulC]

Red Green would be proud, although I think I would have stopped with something nameplated at 200 pounds when trying to lift something weighing 5 or 6 times that. That's a pretty good stretch of the engineers 1.5 to 2 times safety factor. It was a good idea to use the pipe to allow yourself some distance if it fell. Snapped cables and parts do have a nasty way of whipping, so even more distance would be better. Be careful!

Edited to add: Oops, didn't read far enough to see that the point was weighing it. Presumed it was another link in the lifting "chain". Sorry...

[ 12-01-2004, 07:53 PM: Message edited by: PaulC ]

[Bruce Hooke]

That's pretty clever, and unless I am much mistaken the load on the spring scale was never more than 200# because it was on the "light" side of the tackle.

[Paul Scheuer]

If you're up for an experiment, you could try another method that would take the pulley friction out fo the picture. Then see if it's any more acurate.

Hang one end of a beam by your big chain.

Position your hook 1/10 th of the way from the chain point with anothjer hefty chain.

Hook your "fish scale" 10/10 ths of way out.

Hoist the load clear with the tackle, or whatever.

Your load will be 10X the fish scale weight.

(you'll also be clear of the action while you read the scale).