I'm a bit puzzled where Oldham comes into this, if she was in Blackpool.
If she was in Oldham, might she have
not been a member of the Blackpool Lifesavers Club (that existed: see
http://website.lineone.net/~moyes.pr/lifesavers/area_reports.html, but that website doesn't appear to have been updated for years and the
www.blackpoollifesavers.org.uk website is no longer accessible) but someone who just happened to save a life at Blackpool while she was on holiday there?
I'm not trying to be disruptive, but thinking around it more, and you don't actually say
how you "found out that my great grandmother, Nellie Smith was a lifesaver in Blackpool in the early 1900's".
Aha. I've just noticed you've said she was born in Bardlsey in 1888. If this is the Nellie Smith who's the daughter of Thomas & Hannah, she's in Crompton, north of Oldham on the 1891 and 1901 censuses. Now I understand the Oldham connection.
Do you know if the family moved to Blackpool? (they could be looked up in trade directories of the time)
I had a quick look for the family in the Outward Passenger Lists on Ancestry but couldn't spot them, though I think it's still too early for the UK passenger lists to give the address they were leaving in the UK.
If she saved lives in Blackpool, I'd have thought that this would be have been mentioned in the local paper, the Gazette (
http://www.blackpoolgazette.co.uk). Sadly, like many local newspapers, I don't think they have any online archive, and I don't think they're on Findmypast's British Newspaper Collection. But a letter to them, particularly if you give them copies of your photos of Nellie and can provide dates, might pique a journalist's interest or they might just publish your query in full to pass it on to their readers. I know I'm a bit cynical, but local papers are always looking for stories, and a female lifesaver in the early 1900s would, I reckon, be just as "newsworthy" then as it is now.