What is this block?

[JimConlin]

A friend has acquired this, What do we know about it?
A565C495-5F4C-460F-B564-27897D7ECD79.jpg

[Canoeyawl]

Looks "Herreshoffie"

[sp_clark]

It's elegant, beautiful in fact!

[Peerie Maa]

If it wasn't for the shackle I would have guessed it maybe wasn't even nautical. It's common here to have clothes line supported both ends by pulleys like that mounted on wrought iron arms on the outside of you house. you reach out the window, peg the clothes pull the line along abit . peg the next item.
Or flag pole kit?

We have those as well, but they are usually galvanized cast steel and painted white, not polished bronze.

[Peerie Maa]

This is marketed as a Herreshoff Yacht Pulley

[ShorelineJohn]

Sure would be fun to make a casting of it.
Not that I have skills like Jim Ledger, but it sure would be fun trying.
Maybe I'll try something like that this winter.

[JimConlin]

This is marketed as a Herreshoff Yacht Pulley

Marketed by whom?

[Peerie Maa]

Marketed by whom?

Several outlets. Google is your friend.

[rbgarr]

Herreshoff designed it to be a lighter version of their standard block that had enclosed bronze cheeks.

[JamesCaird]

We referred to them as "skeleton blocks".

[lupussonic]

Beautiful...

Design, engineering, casting knowledge...aesthetics...patina.. stunning.

Do NOT polish it!

[HCR]

Forgive me for being late to the discussion, but just for the record this is most definitely NOT a Herreshoff-designed or -made block. All the drawings for Herreshoff blocks can be seen on the MIT website. There is not a single drawing for such a "skeleton block" --- as intriguing as this block may be.

There are many "Herreshoff blocks" on the internet but few of them were really made by Herreshoff or are true to the original design. The same applies to "Herreshoff cleats".

[SKIP KILPATRICK]

The Herreshoff Yacht Pulley I can understan how the sheets run.

My mind's eye is struggling with how the sheets would run in that skeleton block in the OP.

I cannot see how they would be free running. The pully appears to be captured all the way aroiund.

[Dave Hadfield]

It's definitely not the block you want banging on your deck, or against a wooden spar.

[earling2]

Beautiful but that bronze pin looks like it would collapse under a decent sheet load, to me.

[holzbt]

Sometimes referred to as "Cage" blocks. They were intended to help minimize weight aloft.