A curious fitting

[team karst]

It swivels. Is it also a breakaway device?

[Nicholson58]

It looks like devices I used in machine design. If so, it would have a stack of disk springs or a serious coil spring inside to accept impact tensions.

[team karst]

Ah, so maybe its extends with high loads. It came in ships spares on my sailcat.

[StuM]

It's a furling halyard swivel. Very similar to the one on the halyard for my furling screecher, but I can't identify that specific one.

[Wotname]

Swivel???
The thru bolts suggest it doesn't break way.

[tkeithlu]

Does not break away, although it and any other swivel can break. It is not a through bolt, but two bolts, so it can swivel. It absorbs shock through an internal compressive spring. Use it wherever you need that feature.

[Wotname]

Originally Posted by tkeithlu

Does not break away, although it and any other swivel can break. It is not a through bolt, but two bolts, so it can swivel. It absorbs shock through an internal compressive spring. Use it wherever you need that feature.

The thru bolts I was referring to are thru bolts; there are four of them. Then there are the two bolts you are referring to which as you say, are not thru bolts.