Basically, if a ship breaks down and has to be rescued/towed to a safe anchorage there can be a claim for salvage. Its a very complicated legal process but if all the criteria are met the insurers pay out an award based on things such as the value of the ship and its cargo.
The award is then divided up using a set formula and after Mr Brown gets his cut ( ) I get some money
I have done 15 salvages and have been paid for 7 which is a petty good average.