Valerie Burton, Chair of the Maritime History Research Unit at the Memorial University in St John's, Newfoundland, gave this talk at The (UK) National Archives on 8 December 2011. She is knowledgeable and speaks clearly.
I wish I could recommend the podcast more enthusiastically. But despite her mentioning the problem faced by people listening to the podcast of not having the visual aids used in the room she ended up not making adequate allowance. The impression I got was of a lot of good content not particularly well organized, a comment made more generally by students on her page at RateMyProfessors.
The problem was exacerbated by the inaudibility of some passages, something I've commented on frequently. You'd think TNA could have done something about it by now out of simple courtesy to listeners. In person in the room it's not an issue as most speakers don't need the sound system; but one wonders if anyone from TNA ever checks to experience the frustration to which they are subjecting podcast listeners.
Link to the podcast through http://www.nationalarchives.gov.uk/podcasts/nineteenth-century-merchant-seafarers-records.htm but you may do as well perusing the Maritime History Archive website at www.mun.ca/mha/mlc.