I would have to agree with Orac re Stan Rogers' 'Last Watch on the Midland' as sung by Marillyn Middleton Pollack. My eyes are wet now just thinking about it.
Jez Lowe's 'Last of the Widows' usually gets to me, and there's a song called Red Falcon IIRC about a Fleetwood trawler sinking, I have heard it twice and been in tears both times.

Cavia_P