Hi, Rita.
Although I will be at the Getaway (hurrah!) with the Shellback Chorus and have a wonderful time singing shanties and sea songs with them, my first and abiding love is for Irish traditional (unaccompanied) songs, and associated songs from the English and Scottish traditions.

I would be very happy to take part in or lead a workshop-type-singaround along these lines, perhaps with the help of a couple of other Shellbacks, providing of course that these didn't interfere with Shellback commitments. Perhaps a ballad workshop, with input of ballads from the different traditions from both sides of the Atlantic?

As you suspect, Shellbacks are a talented bunch in a number of fields, including (off the top of my head) English music-hall songs and humorous songs as well as non-maritime chorus songs. Anywhere a few Shellbacks gather is a focus for rousing chorus/harmony singing- so be warned!

While I wouldn't presume to volunteer anybody else, I will mention that you're looking for volunteers :0)