Complex sentence: After sea trials and going to F.o.s.t she was deployed to go to the Falklands during her passage HMS Northumberland had to divert into rough weather to save a Fishing Trawler.
Split into simpler sentences: After sea trials and going to F.O.S.T. she was deployed to the Falklands. During her passage HMS Northumberland had to divert into rough weather to effect the rescue of a fishing trawler.