In case y'all missed it, you now have yet another maritime work song function that falls outside the scope of the shanty. Command & control (conn.)

“...one always gazes at the compass, and chants a kind of sweet song, which shows that all is going well, and in the same tone he chants to him that holdeth the tiller of the rudder, to which quarter the rudder itself ought to be moved:...” [Fabri]

“CUNA, (p. 63.) a sea term; quas. cun a’. To cun a vessel, is, to give directions to the steersman; for which purpose, a person is employed, who chaunts, from time to time, his directions, in a high tone of voice.” [Leyden]

“SONG. The call of soundings by the leadsman in the channels....” [Smyth]

Lyr Add: Mark Twain (Harry Belafonte)
(^Not to be taken seriously.)

See image of Qar's tomb [links above.]
The proreta on the prow of Qar's funerary barge is holding a long pole, Gr. kontus. If the water is too deep for the pole to reach bottom he measures with the lead line but cannot help steer &c.

Also:
Quant pole
contour line
Conn (nautical)