Jerry-

You initially asked if sea music groups have similar issues with harmonizing. Ours does, and the discussion certainly sounds familiar. However, some scholars maintain that traditional shantying (the works songs at sea) never involved harmonizing in the chorus or refrain, with the possible exception of black sailors. Like all generalizations this one may not survive the test of time, but we may require a time machine to conduct the test. Lord knows that work about ship was difficult enough without extended discussion of who was on someone else's note!

My group, Roll & Go, prefers to harmonize on the chorus or refrain, and sometimes with a single person harmonizing on part of a four line verse with the lead singer. There is also usually one person echoeing the melody in a different octave. The harmonizers sometimes pass by one another on a shared note but we try to avoid parallel harmony. We also sometimes take off from a shared melody note on land one one at the end of a line. I'm not sure how one would more technically describe that but there are a couple of members within our group who actually know what they are doing.

With a new song we generally evaluate each member's harmony attempts with the lead by playing guitar chords. Then we either record the successful ones or attempt to remember what works...

Cheerily,
Charley Noble