Hi Hammers – nice engraved coin you have there. Personally I think it may be worth a little more as it refers to an actual historical event which happened on the same year as the coin itself. here If you can find out how your grandfather came by the coin and discover the story behind the coin this will add more value,1916 in the scheme of things is not that far back. Engraved coins are becoming more popular and I would imagine if you put that on ebay today you might get around £100 – more you can provide a history and if someone was particularly interested in Maritime history. However as anything fashionable, do this in 5 years time you may get substantially more or less.