consort ship; accompanying vessel
A ship that sails together with another, often for escort, support, or companionship. Nautical term.
boarding a ship together; joint boarding
The act of two or more people boarding the same vessel together. Somewhat literary or formal.
They set off on a journey, boarding the ship together.
A consort ship accompanied the fleet for resupply.
Standard kanji spelling for both senses; 友 suggests companionship or togetherness.
Alternate spelling using 伴 (accompany); less common but still encountered.
Compound of 友 (とも, 'friend, companion') + 船 (ふね, 'ship, boat'), with rendaku voicing ふね → ぶね. The spelling 伴船 uses 伴 (とも, 'accompany') with the same reading.