In the forward bilge there were 2 large cylinders filled with water welded directly to the inside of the hull. Trying to figure out what purpose these served. Given some dates are stamped on the units are early 1940s during the time Fifer was used for the war effort a probably source is military.
Mystery cylinders removed
Speaker cone? 2 wires connect to the coil in the middle of the cone.
2 units removed from hull, this is roughly 1/3 of the way back from the bow
Possible control box? Admiralty Part Number 5860
*Admiralty Pattern Numbers were numeric part numbers the British Admiralty used to name various pieces of naval equipment.
Source: http://www.dreadnoughtproject.org/tfs/index.php/Admiralty_Pattern_Number
Anyone know what these 2 units are all about?
Fifer Yacht 1939 
Hello. This is no doubt the housing for sonar gear employed aboard Fifer during WW TWO when she was seconded to the Royal Canadian Navy as a submarine hunter. Apparently she was just some miles to the North of Estevan Point when a Japanese submarine surfaced and lobbed a few shells at the lighthouse. Other than scaring the wits out of the light keeper the shells did little damage.
John Manning
Captain aboard Fifer during her time with owner Melvin Belli during the 1980’s