You can add a fake ammobox to any object.
Just place an ammobox on the map and name it ammobox and in the init put this hideobject true
In the boats init put this
this addaction ["CRRC-Gear","ammobox.sqf",[], 6, true, true, "", "(_this distance (_target))<2 and !(player in _target)"];
and for the code it's just this
_Player = _this select 1;
ammobox setpos position _player;
_Player action ["Gear", ammobox];