aboard a warship; on a warship
Refers to being on or related to the deck or interior of a military vessel. Often used in compounds like 艦上機 (carrier-based aircraft).
艦上での生活は厳しい規律に縛られている。
Life aboard a warship is bound by strict discipline.
艦上機が甲板から発艦した。
A carrier-based aircraft took off from the deck.
carrier-based aircraft
carrier-borne attack aircraft
Compound of 艦 (warship) and 上 (on, above).