Regarding the Stewart's career, I've found an entry in the London Gazette number 30683 that HM Ships Myosotis, an Arabis Class Sloop and Bluebell, a Flower Class Sloop along with three armed trawlers, INA Williams, Reindeer II and Lucinda, received salvage money for the recovery of SS Alexandrian between the 9th and 11th Jan 1917. It sounds like quite a complex salvage operation to commend the attention of 5 ships.
The newspaper article on page one says that Stewart survived two torpedo attacks, perhaps this was one of them.