During the height of the Cold War if I remember correctly the R.N. in the 1950's had a programme of dispersing coastal wrecks with explosives to flatten them preventing Midget Submarines hiding in their shadow especially those wrecks near Ports and Anchorages.

One Wreck they didn't flatten was the explosive filled Richard Montgomery, apparently it has been decided by the the Authorities that her Masts need removing due to concerns about corrosion on both Masts and Deck putting pressure on the rest of the Wreck due to Tide flow, the 2million pound Contract has been awarded to Briggs Marine under R.N. Supervision I understand, I don't think the Brave Divers will be looking for the Silver Dollar(s) under the Mast(s)
Tin Helmets are available in Army Surplus Stores in Southend as well as a number of inflatables for a possible tidal wave although Southend has been crossed off the holiday destination for the time being by many I suspect