shuts down they have been known to take all but a refrigerant repair crew for it off."
95% of the ships don't have refrigeration plants onboard, we maintain the cargo pressure (or NBO Natural Boil-off) onboard by using the cargo in the main/auxiliary engines. This might be steam turbine ships or the new generation DFE (Dual Fuel
The ships which has Reliquification Plants onboard has two units onboard, then there is a GCU (Gas Combustion Unit) which is a back-up. Lastly there is is the final option to vent - this is not taken lightly, but is only a last resort.
At no time is the ship crew allowed to leave - leaving a ship will again by a final resort when all is lost
There are different sizes of these ships ranging from 130,000m3 - 210,000m3.
The cargoes are carried at -160 deg Celsius (no typo, its -160).
As far as BLEVE's go - The next time you pass one of these ships, have a look at the masts on the ship. They are venting masts, when all has failed these masts will automatically open (mechanically, no need for power or signals/inputs) to firstly insure the cargo tanks
don't over-pressurise and secondly to vent excess gas to atmosphere. LNG (or methane) is the only gas which becomes "buoyant" when at ambient temperature and will "float" off. This means that the gas cannot accumulate in one area on deck
or at sea level.
If you see an cloud of LNG it will normally only be the outer layer that can explode due to LEL/UEL (Lower/Upper Explosive Limits). The cloud dissipates in seconds.
People far cleverer than us has made sure that every aspect of safety
has been looked at when constructing and managing these ships.
Even when we, the crew, mess up the ship will only allow us to "mess up" so far before the automatic system takes over (these cannot be overridden).
There has been groundings/collisions - there still hasn't been any failure of the containment systems.
Two giants collided: Hanjin Italy vs Al Gharrafa in Malacca Strait| SeaNews
LNG Carrier Grounded off Nigeria May Offload Cargo to Break Free - gCaptain
People are very afraid of these ships, because they don't know them. Some countries close the whole canal just to let us through without the risk of having an accident
, with other countries where seafarers have knowledge - its business as usual.