Brian Bedford of Artisan has written a similar song "I'll sail no more" which might be an alternative. I'm sure a search will find you a copy of it on CD. Plenty of opportunities for harmony, as you'd expect from Artisan.

If I've accepted a booking for a general gig, I do my stuff, no requests. If the gig is a special occasion, and I get asked in advance for a particular song, I'll give it a go. I do not do requests off the cuff (I'm neither that versatile nor experienced enough), but for a particular event I will select some material not in my usual repertoire to suit the occasion.