Hydraulic Line Hauler - Block Pully Question

[Beltzington]

This is off topic but couldn't find a better place to post my question -

I was a fan of the Deadliest Catch until they made it a drama-queen competition but they are running a marathon over the holidays so ended up watching a few episodes. My question is:

How does the crab pot "block" work? I can't understand how it creates enough friction to pull several hundred feet of line and almost a ton of pot and crabs by simply draping the rope over the powered pulley. Searching the web I was only ably to find how it was built and how to use it but not how it works.

I am sure someone on this form has the answer.

Happy Holidays!

 

[DLTTrekkers]

The outside of the rope slides down to the smallest diameter and the rest of the turns friction against it. By keeping the loose end tight the work gets done .

 

[RNeumann]

It’s the deep V of the pulley and the other 2 idler pulleys are more than 180° “around the drive pulley. This creates way more friction than you would think. Plus the more weight that is added the more friction/tighter it gets.

 

[DLTTrekkers]

Can not be used on a V pulley

 

[DLTTrekkers]

He talkes about the fishing industry

 

[bcp]

some photos:

Line Haulers - Seawinch

Pot Haulers - Blue Ocean Tackle Blue Ocean Tackle

Quality Products Northwest Crab & Shrimp Pot Pullers - Light Commercia

Bruce

 

[Beltzington]

Appreciate the replies,

It surprises me that simple friction on a wet, possibly frozen line would work but I will take your word on it. Thinking it over it is basically an inverted wheel and the rope is the pavement.

Merry Xmas