Source : Webster's Revised Unabridged Dictionary (1913)

Volunteer navy \Vol`un*teer" na"vy\
   A navy of vessels fitted out and manned by volunteers who
   sail under the flag of the regular navy and subject to naval
   discipline. Prussia in 1870, in the Franco-German war,
   organized such a navy, which was commanded by merchant seamen
   with temporary commissions, with the claim (in which England
   acquiesced) that it did not come within the meaning of the
   term privateer.