"In the 1930s a fisherman caught in his net an old almost unrecognizable Francis Patent lifeboat that probably came from

http://www.youtube.com/watch?v=rUO0Dmip7o0

The Harpoon sounding machine is a brass depth log that works by counting the revolutions of a rotor as the log is lowered to the seabed. There are two dials, one reading from 0 to 30 fathoms, the other from 0 to 150 fathoms. The rotor is free to rotate as the log is lowered, but when the line is drawn up again a locking piece drops down and holds it in place. The log has a piece of rope attached to it and is held in its original wooden box, which has a set of printed instructions inside the lid.

Also found to be useful in performance of the "octupus loosening" (translation from Tongon), a song performed underwater in a circle of 8 to lure the aquatic delicacy towards it's human enemy. (Taken from diaries of '41)

octopus: a local delicacy. to lure, underwater (in a circle of 8) or, alternatively, a jews harp may be substituted

(n.b. note "the uncommon smallness and delicacy of their singers"- elusion to cannibalism, perhaps)