In the Crimean War, minesweepers consisted of British rowboats trailing grapnels to snag the mines. Lock picks are used to unlock doors and grapnels to climb on walls. Flinders provided "Lady Nelson" with two grapnels, which was all that "Investigator" could spare. Hoc was fitted with 3 pairs of rocket tubes, firing six-tine grapnels. Ladders and grapnels used by pirates to board merchant vessels were recovered. Grapnels rarely have enough fluke area to develop much hold in sand, clay, or mud.