🔍 Key Concepts

• How LNG (liquefied natural gas) carriers use boil‑off gas (BOG) during normal operations • Whether it is acceptable on gas carriers to vent flammable gas to atmosphere in normal service • Typical use of cargo boil‑off as a fuel source on steam turbine LNG carriers

💭 Think About

• Think about what shipboard system can safely and economically use a steady flow of flammable gas during the entire voyage. • Ask yourself: is it practical to recompress and reliquefy all boil‑off on every LNG carrier, or is there a simpler routine use for that gas? • Consider which choice would match both safety (no gas clouds on deck) and energy efficiency (not wasting fuel).

✅ Before You Answer

• Eliminate any option that would routinely discharge flammable gas to atmosphere in normal operation. • Consider whether nitrogen is normally mixed with cargo gas on LNG carriers or if the cargo must remain very pure. • Recall that traditional LNG carriers have large steam plants—how might they fuel their boilers during the voyage?