Four sheeve block tackle problem

[DavidTocher]

I know there is a clever way to pass the rope through a pair of three sheeve blocks with the axles at right angles which avoids the ropes rubbing.

I found a Haltrac block assemblies which has; four sheeves on each block, a becket below the middle sheeves and a jammer on one of the middle sheeves.
Does anyone know if a similar reeving exists for the Haltrac? If so, what is it?

 

[cliff]

[ QUOTE ]
I know there is a clever way to pass the rope through a pair of three sheeve blocks with the axles at right angles which avoids the ropes rubbing.

I found a Haltrac block assemblies which has; four sheeves on each block, a becket below the middle sheeves and a jammer on one of the middle sheeves.
Does anyone know if a similar reeving exists for the Haltrac? If so, what is it?

[/ QUOTE ]

Does this help?

If not try here
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“Artificial intelligence is no match for natural stupidity”
Skype id:cliffillupo

 

[SCGrandma]

Haltrac

I wonder if anyone has an instruction sheet for an item I just found in a box of misc. tools of my dad's. He passed away 12 yrs. ago. The tool I found has the name Haltrac England on it. What is it used for and how does it work? It has 4 ropes and is about a foot from one side to the other and I would like to know how to use it. The rope is abt 1/2 in. dia. My dad was not into boating so I am thinking perhaps he used it for something else. What.....I don't know.Help!

 

[ExcaliburII]

I don't know if Haltrac still exist, but they used to make lightweight engine lifting hoists for the amateur/hobby market.

I've still got two of mine in the garage from circa 35 years ago. IIRC they had a SWL of 1/2 ton each, and the rope diameter was about 3/16" (no pansy metric stuff in those days ) using a pair of 4-sheave blocks. They were used to hoik the engine/transmission assembly in & out of my rally minis more times than I can possibly remember and survived a substantial amount of abuse on bigger things, too. They had a sort of self-limiting overload feature in that the used engine oil would get squeezed out of the saturated rope when overloaded and you couldn't grip it well enough to pull any harder.

I don't know what SCG's device is, but if it's got 4 x 1/2" dia ropes maybe it's some sort of lifting beam for adjusting the angle of lift of a suspended load. A picture might help to identify it better.

I can't see cliff's pictures and his link doesn't work for me, so I can't tell if that has answered the OP's query. If not, I will dig out my old hoists and describe the reeving if that would help.

 

[AntarcticPilot]

I know there is a clever way to pass the rope through a pair of three sheeve blocks with the axles at right angles which avoids the ropes rubbing.

I found a Haltrac block assemblies which has; four sheeves on each block, a becket below the middle sheeves and a jammer on one of the middle sheeves.
Does anyone know if a similar reeving exists for the Haltrac? If so, what is it?

I don't have it to hand, but Ashley's Book of Knots contains ways of reeving practically any combination of blocks you want, and quite a lot you've never thought of!

Just checked online: page 531 has exactly what you need.

Ashley's Book of Knots is something no sailor should be without.

 

[rogerthebodger]

In one of PBO's books it shows how to set up a 3 pulley block system.

The trick is to start with the blocks at 90 degrees to one an other and start with the center pulley

 

[Stork_III]

Try the Harken site here, http://www.harken.co.uk/rigtips/Reeving_Diagrams_8-1.php