The pump crank turns easily, and after a few turns water can be heard gushing through the pipes. Atella pulls out his leather case of thieves' tools, but the pump itself has no latch or lock to pick open and none of the tools are hefty enough to break open the barrel of the pump.
A quick search nearby reveals a long metal handspike, perfectly suited for use as a crowbar. With D'Artagnon's help, Atella manages to pop a few rivets on the metals bands holding the barrel staves in. Levering out several f the wooden slats opens up the whole side of the pump, and releases a sluice of stinking bilge water.
In the faint torchlight, D'Artagnon and Atella discover a small, black bundle lashed tightly to the plunger in such a spot as to not affect the motion of the pump.