I have a William Donaldson serving as a deck hand on the Portknockie registered fishing boat BLUEBELL official number 115534 - year of birth 1892. He appears to have served on two half yearly agreements for the whole of 1915. All those aboard were from Portknockie.
I also have a William George Donaldson b. 28 April 1892, Portknockie, serving in the Merchant Navy in December 1918. His CR 10 card also has a mugshot photo of him.
Regards
Hugh