More than 200 invited guests were half way through the second hymn shortly before midday when the call came in.
A 19-foot motorboat with two people on board suffering from hypothermia was in distress in strong winds and high waves.
Realising that the crew, who were already kitted up aboard the new Atlantic 85 rigid inflatable, had to launch, the Dean, the Very Rev Bob Key, quickly changed the order of the service and blessed the boat.
