Patent ID: 7210503

Claim:
A system of preventing water from penetrating into an intermediate section of a pipeline when laying the pipeline on a seabed by means of a pipelay vessel, the intermediate section extending from near the pipelay vessel to near the seabed, comprising a first plug that is capable of sealing the inside of the pipeline and is displaced in the pipeline intermediate section so as to maintain a position in proximity to said pipelay vessel, and in the event of water flowing into said pipeline, said first plug can be locked in a sealing manner whereby water is prevented from filling the said pipeline intermediate section and a second plug that is capable of sealing the inside of the pipeline and is displaced in the pipeline intermediate section so as to maintain a position in proximity to said seabed, and in the event of water flowing into said pipeline said second plug can be locked in a sealing manner whereby water is prevented from filling the said pipeline intermediate section, and wherein a first water sensor carried by said first plug responds to actuate said first plug if water is sensed within the pipeline between said first plug and said pipelay vessel and a second water sensor carried by said second plug responds to actuate said second plug if water is sensed within the pipeline between said second plug and said seabed.