My guess would be Weight and Draft
W.
The Hero of Submarine D-2 - 1916 was released on: USA: 13 March 1916
The Beatles' version of "Yellow Submarine" is performed in the key of D flat major.
W = Wood D = Diamond W W W W D W W W W (as in a crafting table)
W*D=w*d
who what when were why w,w,w,w,w :D
Submarine D-1 - 1937 is rated/received certificates of: Australia:G Finland:S USA:Approved (PCA #3498) USA:TV-G (TV rating)
Water Displacement
DdD dWd DdD written as W surrounded by D or d letters then W = West so the answer is a name: West Indies (West in D's)
D. W. Davis died on 1959-08-05.
D. W. Davis was born on 1873-04-23.
Raymond W. Jenkins has written: 'Infrastructure requirements for a marine minerals processing industry' -- subject(s): Infrastructure (Economics), Manganese mines and mining, Submarine, Submarine Manganese mines and mining