Selection of shell type and fuses depended on the target to be engaged. High Explosive was practically useless against heavy armour. Against light armour, Armour Piercing shells would likely just go in one side and out the other without exploding and doing much damage.
Against lightly armoured vessels (e.g. landing barges, tank landing ships or merchant ships), H.E shells would achieve the best result. Fuse 45P would likely burst against the plating while Fuse 45 or 44 would likely pierce the plating and explode inside the vessel.
Against heavily armoured vessels, an Armoured Piercing type shell (e.g. CPC shells) would achieve the best results.
CPC = ‘Common Percussion Capped’, fitted with a ballistic cap to increase ballistic characteristics of shell and hence range
Above: Shells for 6" BL Naval Guns, mounted in Suffolk Coast Emergency Batteries (with the exception of
Dunwich which had 4" guns)
Easton Wood Battery Fort Record Book, TNA