Not a mandatory safety device, just a good one. Throw lines can be purchased from well stocked chandlers
, safety equipment suppliers and on-line resources.
Versions are available that either clip to your belt or for fixing in an appropriate location in your boat.
They consist of a coil of high visibility floating rope contained in a bag, with a loop attached to it.
To deploy, you put your hand through the loop hold on to it and throw the bag at the person who need rescuing.
They are a compact addition to a life ring system and due to their portable nature can be especially useful for those walking on the bank or working around locks who may need to assist another crew member but cannot reach the on-board systems.
Prices start from around £20 for a 12m model.