Project Tag: Stingray

Cresta & Rock Creek Dam Survey

PG& E contracted Global to perform surveys of four concrete chambers at two separate Dams; Rock Creek Dam and Cresta Dam both located on the North Fork of the Feather River in Northern California. The concrete basins are approximately 25 feet wide by 124 feet long. Global divers accessed the structures through a trash rack and 48-inch inlet; which added an additional obstacle. The total penetration through the pipe and into the deeper area was approximately 35 feet,plus the additional 124 feet to the end of the chamber,necessitated an in-water tender for every dive.

A probe and a scanning sonar were utilized to conduct the surveys and determine the depths of the built up sediment. At Rock Creek,a Steel Wire Rope was established inside one of the chambers approximately 5 feet off bottom. This enabled an MS 1000 sonar to be suspended in order to scan images of the chamber every 5 feet for the entire length.

Inside the same trash rack a 24” pipe was inspected utilizing an ROV; two gate valves had been previously discovered by PG & E engineers to be non-functioning. These 24-inch pipes bifurcated about 25 feet inside the center pier and split off to both chambers supplying water to keep the gates afloat. It was suspected that the pipes and the valves were full of sediment deposited from upstream.

A thorough report providing the data obtained from the sonar images and the probe measurement was provided to the client upon completion of the project.

Hydrogen Reactor Salvage

On December 9th,a 485 ton,140 foot long stainless steel reactor vessel rolled off a barge into approximately 60 feet of water off Cherry Point,WA. One end rested on the sea floor,with the other end,just breaking the surface. Immediately after the incident,Global provided an ROV to inspect the vessel for damage and asses its orientation on bottom. It was determined that there was no structural damage.

Global was contracted to develop,implement and manage the salvage. Over the next two weeks,working closely with the engineers and the owner,a detailed salvage plan was developed to safely lift the reactor from the water and deliver it back to the owner aboard a barge into cradles that were mounted to a transporter for offloading and movement to its final location. Two marine construction companies,General Construction and Manson Construction provided heavy lift derrick barges to lift the reactor and set it back onto the barge.

Divers were utilized to perform a thorough inspection of the structure as well as expose the lifting eye on the bottom edge of the vessel. When all of the plans had been approved and the required assets were in place,divers connected a 400 ton shackle to the lifting eye. The derrick barges,working in tandem at the direction of David DeVilbiss,Salvage Master for Global Diving & Salvage,Inc,lifted the reactor to the surface. It was raised out of the water,the barge positioned underneath and set into the cradles on the transporter.

The reactor is a integral piece of a refinery upgrade,assisting in the manufacture of low sulfur diesel fuel. The vessel was filled with nitrogen to prevent corrosion during transportation.

Kaho’olawe Beacon Recovery Operations

Provide ROV and crew including sonar and CP probe to inspect approximately 25 items (targets) in 450 FSW off of the Hawaiian Islands. The inspection will provide updated positioning and depth of the items and provide a record of their current condition.

FPSO Ship Husbandry

Global provided surface supplied dive team and Inspection Class ROV to conduct visual surveys of the FPSO buoy and components as well as perform light construction and ship husbandry on the hull of the BW Pioneer. Tooling included barnacle busters and high pressure water blasters to remove marine growth.

Lake Don Pedro Salvage

Global Diving & Salvage has been hired to locate a sunken vessel in Lake Don Pedro. The vessel sank in approximately 400 foot of water in steep underwater terrain. To locate the vessel Global will utilize Side scan sonar and an ROV equipped with scanning sonar. After locating the vessel a video inspection will be conducted to determine the vessel condition.

RMS Republic ROV Survey

On January 24,1909,three years before the Titanic tragedy,another “unsinkable” White Star Line vessel sank in 270 fsw of the Atlantic’s most treacherous water. The steam ship,RMS Republic (qualified as a Royal Mail Ship) collided with the SS Florida in a dense fog during the early morning of January 23rd. Over 1,500 passengers and crew were rescued but the vessel sank under tow on January 24,1909 fifty miles off the coast of Nantucket. For more than a century,rumors of the vessel’s precious cargo have persisted.

With the increase in available technology,interest in recovering the rumored treasure of the RMS Republic has grown. Global crews and equipment were mobilized to Groton,CT for an exploratory condition survey of the vessel. The gear was set up onboard the University of Connecticut (UConn) research vessel CONNECTICUT. After 13 hours and 118 miles of sailing,the research vessel established dynamic position above the wreck of the RMS REPUBLIC. Global’s ROV team deployed the Stingray ROV and conducted a video and sector scan survey of portions of the wreck. The results of the ROV survey,combined with other side scan and multibeam sonar surveys conducted,will be used to formulate a plan to access the vessel.