In early August 2017 Crowley Maritime Corp.’s ocean class tugboats and 455-series high-deck strength barges were involved in the successful tow-out and installation of Hess’ Stampede tension-leg platform (TLP) in the deep waters of the US Gulf.
Demonstrating both nearshore and offshore capabilities, six Crowley vessels worked together alongside other third-party assets to deliver the oversized, overweight platform, tendons and other equipment from the Kiewit facility in Ingleside, Texas, to the site of the Stampede floating production facility, about 150 miles offshore in 3,400ft of water.
In the first stage, Crowley’s ocean class tugboat Ocean Wind and the 455-series barges 455-3, 455-5 and 455-7 worked together with other contracted vessels to deliver from Kiewit to the offshore site many 300ft sections of nine 3,400ft tendons that would secure the TLP to the seabed.
From there, the company’s Ocean Sun and Ocean Sky, along with several third-party tugs, towed the TLP through the Ingleside Channel to offshore waters. After a scheduled brief stop at a holding location, the convoy of vessels began the second stage of the tow in offshore waters.
Ocean Sun, Ocean Sky and two third-party anchor-handling tugs safely towed the Stampede hull for four days before reaching the project site.
Upon arrival, Crowley’s tugboats began the third phase of work, positioning and stabilizing the platform using the tugs’ dynamic positioning capabilities while the TLP was secured to the tendons.
Crowley positioned the tugs in a stationary star pattern and used their tow wires to hold the platform steady in the middle. After Hess and its installation contractor, Heerema, completed installation and the platform was made storm safe, Crowley’s assets were demobilised and returned to nearshore waters.