Blow out preventers chaps.
They are the big rubber bag and seals that hold back the pressure in the event of a oil/gas/water kick.
WUZ must be on a semi-submersible where the BOPs are set on the sea bed and in the event of big waves where the mechanical slip joint can't cope with the heave they disconnect the pipe from the BOPs and wait the storm out. the fun bit is connecting back up again.