If a mobile offshore drilling rig has four hand portable fire extinguishers that can be recharged by personnel on the unit, how many spare charges must be carried?

Correct Answer: Option B — 2

Under 46 CFR 108.496, mobile offshore drilling units must carry spare charges for hand portable fire extinguishers that can be recharged on board. For units equipped with up to 10 rechargeable extinguishers, a minimum of 50 percent spare charges (two spares for four extinguishers) must be maintained on board.