The submarine 'Thetis' sank 13 miles of the coast of Anglesey in 1939 during sea trials. 99 men lost their lives and only four survived. The wreck was then beached at Traeth Bychan and subsequently towed back to Camel Lairds at Birkenhead. She was renamed 'Thunderbolt' but was lost in action in the Mediterranean during 1943.

This dipstick and oil filler cap was removed from the submarine whilst undergoing refitting work at Camel Lairds.

These items are on loan from Eifion Hughes, Moelfre.

Source: Moelfre Seawatch Centre