Hello All. I joined the RAF Marine Section in 1956. My first posting was 1110 MU Immingham dock. When I arrived there was a new TTL 2754  an aging 2553 two ST's The ST's later replaced by RSL's. Ihad the pleasure of going out on 2754 on two crash calls and also Target Towing duties. The later was when Neptune bombers who were meant to drop bombs across our wake equadistant of the target a float with scoops which shot plumes of water skyward. but what in fact happened was they would also machine gun the target. Which had to be repaired on a regular basis. A bonus though when it was over we would about turn and pick up many Cod fish that were floating on the surface. Never short of fresh fish.2754 had the 3 Napier Sea lions.When I was posted to RAF Calshot they were ding the Griffon engine change programe.  A further piece of interest is that I worked at one time for a man who Sold off many HSL's equipped with Napier Sea Lions. He offered a service of converting the Arrowhead 12 into a Straight 4 by removing all moving parts of the wing cylinders.also providing a compatable prop to suit