what is this part of life jacket?

[tim_ber]

It appears to be a plastic toggle attached to a piece of string, housed in an elastic enclosure. Elastic enclosure is attached to webbing under bladder.
Hopefully the photos help. When not inflated, the toggle is not accessible.
There is a grab strap and whistle and light aqnd hood, and two pull cords for two gas bottles, so I have no idea what this is for.
Any ideas?

 

[Mariner69]

It is so you can link together in the water with others in their life jackets.

 

[OGITD]

Possibly!?

For tying yourselves together during extended periods in the water, as it also makes it easier for visual location from the air (pre EPIRBs)?

 

[tim_ber]

Right oh, thanks.

Makes sense especially as it is an old jacket.

Why don't modern jackets have them I wonder? Just for the price of a bit of string and plastic.

 

[WilliamUK]

Just for the price of a bit of string and plastic.

Cynical Me thinks you've answered your own question there.
Everything is made to a price... if the bit of string and plastic takes it over that price, it won't be added.
Less-but-still-cynical Me thinks adding up the price of thousands of bits of string, plastic and the time needed to position and fit them would take a rather large chunk of profit out of the margin or add a little to the retail price in a market where most things are priced at £something.95 or .99 to make the price appear lower. I think many would look at a £49.95 jacket and question the sense in paying £52.95 for something that does the exact same job and "won't really be needed anyway".