Curious hardware

[jusw]

I was given these two "tufnol" bits of kit and would like to know approximate age and what they were / are used for - the twin block is fairly obvious, but the other contraption?

The pulley in the centre is toothed and has a little silver cam that looks like it should engage, but doesn't!

On the left hand end of the picture is a spring loaded fitting presumably to act as some sort of shock absorber.

Anyone any ideas? I'm just curious.

JuSw

 

[Stork_III]

The "other contraption" is a rachet block or at least the toothed part is. Under load the silver lever moves towards the sheave and engages in the rack, allowing rotation only one way. Ie sheet can come in but not back. Release some tension rachet disengages.

 

[Pasarell]

I agree with Stork_III, it's a ratchet block that should freewheel when no load but lock up if tension kept on the free end. I first came across them in early 70's

 

[Cuan]

+1 it's a ratchet block, my dad had one on the main sheet of his Osprey back in the late 60's

 

[jusw]

A ratchet block makes sense, but I don't see how it works, the "pawl" doesn't move enough to engage in the teeth in the centre of the pulley - perhaps its broken or worn away? -

Can anyone sketch out the path the rope takes through the block?

JuSw

 

[Searush]

The pulley wheel should slide under the weight of tension on the main sheet until the ratchet engages. Once there, only slight pressure is needed to hold it engaged. Release the pressure completely & the rope will run freely.

It makes it much easier (less effort needed) to keep a sail sheeted hard on the wind.

If you don't want it, post it to me, it is a perfect contemporary fitting for my vintage GP14.

If the two blocks were together I expect they were part of a mainsheet system.

 

[knuterikt]

A ratchet block makes sense, but I don't see how it works, the "pawl" doesn't move enough to engage in the teeth in the centre of the pulley - perhaps its broken or worn away? -

Possible or a jammed spring

Can anyone sketch out the path the rope takes through the block?

JuSw

These two blocks does not look like a pair..

The ratchet block is a fiddle block with becket, it would normally be paired with a fiddle block w/o becket and ratchet.
Like this - bottom block is your ratchet block

You can replace the top block in this picture with your double block but it looks a bit out of place.

 

[ianat182]

Tufnol blocks of that vintage were made from about the 1950's by M.S Gibb, Main Marine and as you have there ,Lewmar(Lewis Marine); as mentioned ,they were the bee's knees for the GP14 and Firefly/Albacore/ and Int 14's. I have the same ratchet block type; the last time it was fitted was for an experiment in centre-mainsheeting in my vintage Merlin Rocket later replaced with a Seasure lightweight set of pulleys. If nothing else they are durable and reliable and I use a couple for my cruising chute sheets on the Tiger.

ianat182

 

[nigelmercier]

+1 it's a ratchet block, my dad had one on the main sheet of his Osprey back in the late 60's

I was just thinking, I'm sure I had one of these on the main sheet on my Fleetwind in the 70's. It was designed to lock up part way through a gybe.

 

[Salty John]

The first block is typically used for running backstay tensioning systems. You see modern equivalents from the big block manufacturers on Americas Cup boats - the yoke support with large diameter sheaves is the same now as it was when that tufnol block was made.

The other is, as has been said, a ratchet block.

 

[jimi43]

The ratchet block is used as shown by others who have posted but you will need to adjust it to get it to lock in the ratchet at the correct pressure.

You can do this by rotating the chrome eye attached to the spring (right hand side in your picture)....

At the moment you have it set to quite high pressure (spring 2/3 depressed)....as you rotate the eye bolt the thread slowly allows the wheel to move towards the ratchet arms and lowers the point at which it will engage.

Try winding it completely out so the spring is not depressed at all and at the same time rotate the wheel. You will notice at some point the ratchet engage and click.

Hope this helps.

By the way...I don't sail but I have one of these to open the dome on my telescope observatory! It is a wonderful bit of kit from about 50 years ago...still in service and like new. They don't make things like this any more...pure quality!

Cheers

Jimi