SPOTD: Seven Waves’ New High Capacity Pipelay Tower

subsea 7 seven waves pipelay vessel
Image via Huisman’s Facebook page

Last October, Subsea 7’s new pipelay vessel Seven Waves, arrived at Huisman Schiedam to receive its 550 metric ton flex-lay system and 400 metric ton active heave compensated offshore mast crane.  These systems have now been installed and pictured above in the undated photo.

The 145.9 meter LR-classed vessel was delivered from IHC Offshore & Marine’s shipyard in May of 2013, has accommodations for 120, and carries two Hercules work-class ROVs.  She is flagged in the Isle of Man and is scheduled to be delivered in 2014.

The DP-2 equipped vessel has over 18MW of power via six 3,840kW Wartsila diesel engines.

Her pipelay systems include two underdeck storage carousels, with a capacity for 2,500t and 1,500t of product. A vertical (tiltable) lay system (550t top tension capacity) is permanently installed for deployment of a range of flexible products with a diameter from 100 to 630mm. The lay tower can operate at up to 10° and is fitted with two tensioners, each of 275t capacity which can be retracted clear of the firing line, and with two wire centralizers.  The tower is tiltable to allow connection of flexible risers to rigid pipelines which are retrieved from the seabed.

Two A&R winches are fitted of 600t and 200t, both with 2,500m of wire. The moonpool is designed to hang off products up to 600t and is fitted with a mechanism to allow the product to be rotated under full load.

The Seven Waves is the fifth vessel to be built by IHC Merwede for Subsea 7.  The other ships include:

  • Seven Ocean (pipelaying)
  • Seven Seas (pipelaying and construction)
  • Seven Atlantic (diving support)
  • Seven Pacific (pipelaying)

Once delivered, Seven Waves will head to Brazil where she will support Petrobras’ deepwater oil field development work.