The vessel sank off the coast of Guernsey on the night of 16 January 1974 with the loss of all the crew.
They are commemorated on a memorial at the headland.
‘This tragedy affected not only those on board who lost their lives, but also all other incredible men and women who tried their best to save them,’ said Father Joe Thompson in his sermon at Saturday morning’s service.
‘Maritime disasters similar to the sinking of Prosperity continue to happen, so it’s fitting today that we also hold up all those who brave the weather to go out and rescue strangers they do not know from the clutches of this beautiful yet cruel mistress.
‘Today we remember the crew who died on the Prosperity, and we pray that their families may know that Guernsey does not forget. We pray that they may have some comfort from us gathered here today.’
Among those who attended the service was former harbour master Tim Spencer who recalled meeting the owner of the Prosperity after the tragedy. He said it was good that people still gathered to remember the crew.
‘It was a great, great tragedy,’ he said.