Hi ANgus,

I found two hits in the National Archives UK that might be your man:

BT 372/52/74 R126104 MACINNES A 26/12/1905 SKYE
BT 372/52/101 R126249 MACINNES M 24/09/1917 SKYE

These relate to the Registry of Shipping and Seamen: Central Register of Seamen: Seamen's Records ('Pouches').

Not knowing his DOB makes it a bit tricky, but it he was born in 1905 he could still have seen service aboard a boat by wartime and been torpedoed late in the war.

Onward through the fog.

-Daniel