Outer Continental Shelf National Center of Expertise (OCSNCOE)
OCS-Related Accidents, Investigations and Safety Alerts
This page consolidates information pertaining to OCS-related accidents, investigations and safety alerts/lessons learned. Use the tabs above to view the following categories:
1) U.S. Coast Guard Investigations;
2) National Transportation Safety Board (NTSB) Marine Accident Reports and Marine Accident Briefings;
3) USCG Safety Alerts and Lessons Learned (with access to additional USCG and Bureau of Safety and Environmental Enforcement (BSEE) alerts);
4) DEEPWATER HORIZON/Macondo Well Blowout, April 20, 2010; and
5) FPS AUGER Lifeboat 6, June 30, 2019.
U.S. Coast Guard Investigation Reports for OCS-Related Casualties
The U.S. Coast Guard prepares and publishes reports of investigation that present the findings of fact, results of analysis, conclusions, and recommendations of the Coast Guard's investigation of marine casualties, outer continental shelf (OCS) casualties, and commercial diving casualties. This page lists USCG reports that are OCS-related, ordered from newest to oldest (by accident date). Additional investigation and casualty analysis reports are available on the Office of Investigations & Casualty Analysis (CG-INV) Marine Casualty Reports page.
Click on the accident date to open the document (opens in a new window).
NTSB Marine Accident Reports (MARs) and Marine Accident Briefs (MABs)
National Transportation Safety Board Accident Reports "provide details about the accident, analysis of the factual data, conclusions and the probable cause of the accident, and the related safety recommendations". This page lists NTSB Marine Accident Reports that are OCS-related, ordered from newest to oldest (by accident report number). Additional accident reports and information are available on the NTSB's Accidents Reports page.
Click on the report number to open the document (opens in a new window).
Overturning of the Liftboat KRISTIN FAYE
Summary: On September 8, 2019, about 1015 local time, the liftboat Kristin Faye overturned while preparing to conduct work alongside a platform in the Gulf of Mexico, in Main Pass Block 64, located about 18 miles east of Venice, Louisiana. All three crewmembers abandoned the vessel and were rescued. One person suffered minor injuries during the evacuation. An estimated 120 gallons of diesel fuel were released. The vessel was declared a constructive total loss at an estimated $750,000.
Fire aboard OSV GRAND SUN
Summary: On October 8, 2018, about 0215 local time, the offshore supply vessel Grand Sun was transiting the Chandeleur Sound in the Gulf of Mexico, about 15 miles from the Chandeleur Islands, Louisiana, when the vessel caught on fire. The four crewmembers aboard attempted to fight the fire but were unsuccessful. They remained on the stern of the vessel until they were rescued by the US Coast Guard. The fire burned itself out, and the vessel was later towed to port. No pollution or injuries were reported. The vessel, valued at $1.6 million, was deemed a constructive total loss.
Overturning of the Liftboat RAM XVIII
Summary: On November 18, 2018, about 0200 local time, the liftboat Ram XVIII overturned in the Gulf of Mexico, in West Delta block 68, located about 15 miles south-southeast of Grand Isle, Louisiana. Five crewmembers and ten offshore workers abandoned the vessel and were rescued. Three personnel suffered minor injuries during the evacuation. An estimated 1,000 gallons of hydraulic oil were released. The vessel was declared a constructive total loss at an estimated $1,140,000.
Collision of OSV GLORIA MAY and Fishing Vessel CAPT LE
Summary: The offshore supply vessel Gloria May collided with the uninspected fishing vessel Capt Le in the Gulf of Mexico about 2040 on the evening of August 24, 2014. As a result of the collision, the hull of the Capt Le was breached and the vessel flooded and sank; the bow of the Gloria May suffered minor damage. Three crewmembers from the Capt Le abandoned their sinking vessel into a liferaft and were recovered by the crew of the Gloria May. No injuries resulted from the accident. Total damage was estimated at $225,000.
Collision between Passenger Vessel DIAMOND EDGE and Liftboat B.W. HALEY
Summary: On March 2, 2015, at 1027 local time, the passenger vessel Diamond Edge and the liftboat-configured offshore supply vessel B.W. Haley collided while under way in dense fog about 55 miles south-southwest of Lafayette, Louisiana. As a result of the collision, the hull of the Diamond Edge was breached and the vessel partially sank. There were no significant injuries or pollution reported. Estimated damage exceeded $1.75 million for both vessels combined.
Allision of OSV CONNOR BORDELON with Unmanned Platform South Timbalier 271A
Summary: On January 23, 2015, at 0432 central standard time, the offshore supply vessel Connor Bordelon struck the unmanned natural gas platform South Timbalier 271A, which was located about 5.25 miles south of the jetty channel entrance at the vessel’s home port of Port Fourchon, Louisiana. The allision caused the pipelines attached to the platform to rupture and the natural gas and oil inside the pipelines to ignite. After the allision, the pipelines were shut down, and three good Samaritan vessels in the area applied water to put out the fire. The allision also caused a breach in the Connor Bordelon’s hull below the waterline, and the vessel began taking on water. The captain contacted the US Coast Guard to report the accident, and the Coast Guard released the Connor Bordelon from the accident area and allowed it to continue to Port Fourchon while the crew addressed the flooding. None of the 24 persons aboard the vessel were injured.
Allision of OSV TRISTAN JANICE with Natural Gas Platform
Summary: About 0712 local time on February 18, 2014, the US-registered offshore supply vessel Tristan Janice allided with a natural gas production platform in the northern Gulf of Mexico, about 54 miles south-southwest of Houma, Louisiana. No one was injured and no water pollution resulted from the allision. However, the vessel and the platform sustained about $545,000 in total damage, and a substantial amount of natural gas escaped into the atmosphere from a ruptured supply pipe.
Subsea Pipeline Damage by Tug and Barge VALIANT/EVERGLADES
Summary: The articulated tug and barge (ATB) unit Valiant/Everglades lost propulsion and drifted to within about 20 yards of the East Cameron (EC) 321A production platform in the Gulf of Mexico, forcing the shutdown of the platform and evacuation of its 35 crewmembers about 0600 on November 17, 2014. The captain of the Valiant ordered the anchor dropped to slow the vessel until propulsion was restored, and in the process of backing away, the anchor ruptured a subsea pipeline, causing an estimated $2 million in damage and the release of a total of about 249,800 mcf of natural gas. Neither the platform nor the vessel was damaged, and no one was injured.
Fire on Board Saturation Diving Support Vessel OCEAN PATRIOT
Summary: A fire that broke out in the forward machinery space of the saturation diving support vessel Ocean Patriot while under way in the Gulf of Mexico on the evening of November 28, 2013, was brought under control by the vessel’s fixed fire suppression system without serious injury, and no pollution resulted from the accident. Damage to the Ocean Patriot was estimated to be $9.8 million.
Allision and Sinking of Offshore Supply Vessel CELESTE ANN
Summary: The offshore supply vessel Celeste Ann was receiving passengers from West Delta oil platform 73 about 20 nautical miles southeast of Grand Isle, Louisiana, when the vessel allided with the platform about 0836 on June 14, 2013. The allision punctured the hull, and the Celeste Ann subsequently flooded and sank. All passengers and crew evacuated to another vessel, and no one was injured.
Sinking of Offshore Supply Vessel RICKY B
Summary: On May 30, 2013, at 0702 central daylight time, the offshore supply vessel Ricky B sank in the Gulf of Mexico about 24 nm south of Marsh Island, Louisiana, while being towed. The three crewmembers had abandoned the Ricky B earlier and boarded a good samaritan vessel, from which they were subsequently transferred to a nearby manned oil platform. No one was injured. The Ricky B was later refloated. Its damage was estimated to be $520,000.
Fire On Board and Sinking of Liftboat MAKO
Summary: About 0503 on January 16, 2012, the US liftboat Mako caught fire while supporting oil drilling operations about 6 miles off the coast of Nigeria, Africa. No one on board was injured, but the Mako was a total loss in the accident.
Collision of Oil Tanker FR8 PRIDE with MODU ROWAN EXL I
Summary: On May 2, 2012, at 0718, the oil tanker FR8 Pride collided with the mobile offshore drilling unit (MODU) Rowan EXL I in Aransas Pass, Corpus Christi, Texas. No one was injured in the collision, but the two vessels sustained an estimated $16–17 million in damage.
Liftboat TRINITY II, Personnel Abandonment and Loss of Life
Excerpt from abstract: This report discusses the September 8, 2011, accident involving the U.S. Liftboat Trinity II. Ten persons were on board. Because of severe weather and boarding seas associated with Hurricane Nate, the elevated liftboat’s stern jacking leg failed and the onboard personnel abandoned the vessel. Four of them died.
ROWAN GORILLA I, Capsizing and Sinking
Excerpt from abstract: This report explains the sinking of the mobile offshore drilling unit ROWAN GORILLA I on December 15, 1988, in the North Atlantic Ocean. The safety issues discussed are the vessel's design and stability, vessel towing, weather, lifesaving equipment stowage, survival capsule design, survival training, and manning and licensing requirements.
GLOMAR ARCTIC II, Explosion and Fire
Excerpt from abstract: On January 15, 1985, the U.S. semi-submersible mobile offshore drilling unit (MODU) GLOMAR ARCTIC II was conducting well testing operations 130 nautical miles east-southeast of Aberdeen, Scotland, in the North Sea. About 2030, the drilling unit experienced an explosion in the port pontoon pump room. The chief engineer and third assistant engineer were killed in the blast. Damage to the drilling vessel was estimated to be $2.3 million dollars.
ZAPATA LEXINGTON, Explosion and Fire
Excerpt from abstract: About 1230 on September 14, 1984, the U.S.-flag mobile offshore drilling unit (MODU) ZAPATA LEXINGTON suffered an explosion and fire while moored and conducting drilling operations in 1,465 feet of water in the Gulf of Mexico. The accident occurred while procedures were being employed to evacuate a gas bubble from the subsea blowout preventer stack on the sea floor. Instead, gas trapped in the blowout preventer entered the base of the marine riser, rose to the surface, and escaped into the atmosphere, expelling a large volume of drilling mud out of the riser. The gas infiltrated the areas above and below the drill floor at the base of the derrick and was ignited. The explosion and fire that followed resulted in the deaths of four persons and severe injuries to three persons. Sixty-four persons abandoned the MODU using two survival capsules and three inflatable liferafts. The gas fire burned itself out about 30 minutes after the rig was evacuated. The cost of repairs was estimated at $12 million.
GLOMAR JAVA SEA, Capsizing and Sinking
Excerpt from abstract: About 2355 on October 25, 1983, the 400-foot-long United Stated drillship GLOMAR JAVA SEA capsized and sank during Typhoon LEX in the South China Sea about 65 nautical miles south-southwest of Hainan Island, People's Republic of China. Of the 81 persons who were aboard, 35 bodies have been located, and the remaining 46 persons are missing and presumed dead. The GLOMAR JAVA SEA currently is resting on the bottom of the sea in an inverted position in about 315 feet of water; its estimated value was $35 million.
OCEAN RANGER, Capsizing and Sinking
Excerpt from abstract: About 0300 on February 15, 1982, the U.S. mobile offshore drilling unit OCEAN RANGER capsized and sank during a severe storm about 166 nautical miles east of St. John's, Newfoundland, Canada; 84 persons were aboard. Twenty-two bodies have been recovered, and the remaining 62 persons are missing and presumed dead. The OCEAN RANGER currently is resting in an inverted position in about 260 feet of water; its value was estimated at $125 million.
OCEAN EXPRESS, Capsizing and Sinking
Excerpt from abstract: About 1100 c.s.t. on April 14, 1976, the self-elevating drilling unit OCEAN EXPRESS departed a drilling site in the Gulf of Mexico under tow for a new drilling site about 33 nm away. The OCEAN EXPRESS arrived at the new drilling site about 2330, but was not set in place because of adverse seas. Three tugs held the OCEAN EXPRESS in position awaiting better weather, but the seas continued to increase. On April 15, 1976, one tug's starboard reduction gear failed, and another tug's towline broke. With only one effective tug remaining, the OCEAN EXPRESS turned broadside to the wind and seas, drifted, grounded, capsized, and sank about 2115. Thirteen persons drowned in a capsized survival capsule.
Safety Alerts and Lessons Learned
This page lists U.S. Coast Guard Safety Alerts and Lessons Learned that are OCS-related or pertain to systems that are onboard vessels and units that are conducting OCS activities, ordered from newest to oldest (by date). Additional safety alerts from the USCG and BSEE can be viewed at the following pages:
Office of Investigations and Casualty Analysis (CG-INV) Safety Alerts and Lessons Learned
Bureau of Safety and Environmental Enforcement Safety Alerts
Click on the safety alert number to open the document (opens in a new window).
DEEPWATER HORIZON - Macondo Well Blow-Out
The DEEPWATER HORIZON mobile offshore drilling unit (MODU) was performing drilling operations on the Macondo Well at Mississippi Canyon Block 252 on April 20, 2010 when a series of events led to an explosion and fire that tragically took 11 lives and injured 16 other personnel. Our condolences go out to the families and friends of the 11 men that lost their lives in this casualty.
DEEPWATER HORIZON was severely damaged and sank on April 22. The casualty resulted in the continuous flow of hydrocarbons into the Gulf of Mexico for 87 days before the well was capped, causing the largest oil spill in U.S. history, significant environmental damage to the Gulf of Mexico and personal and economic impact to communities all along the Gulf Coast.
This page serves to consolidate information related to the incident with access to the numerous reports generated by various government agencies and involved companies. All reports are credited to the respective agency or company and are readily available through linked sites or separate internet searches.
Joint Investigation (U.S. Coast Guard & Bureau of Ocean Energy Management, Regulation and Enforcement)
The investigation into this incident was conducted by a joint investigation team consisting of members from the U.S. Coast Guard and the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE). The reports are accessible below, with excerpts from their respective executive summaries.
Excerpt from the Executive Summary: The Joint Investigation Team (JIT) comprised of members from the U.S. Coast Guard and Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) examined five aspects of this disaster relating to areas of responsibility of the U.S. Coast Guard: the explosions, the fire, the evacuation, the flooding and sinking of the MODU, and the safety systems of DEEPWATER HORIZON and its owner-operator, Transocean. Although the events leading to the sinking of DEEPWATER HORIZON were set into motion by the failure to prevent a well blowout, the investigation revealed numerous systems deficiencies, and acts and omissions by Transocean and its DEEPWATER HORIZON crew that had an adverse impact on the ability to prevent or limit the magnitude of the disaster...
Excerpt from the Executive Summary: This Report sets forth in detail the Panel’s investigative findings, conclusions, and recommendations. The Panel’s findings and conclusions are presented in the following subject areas: well design; cementing; possible flow paths; temporary abandonment of the Macondo well; kick detection and rig response; ignition source and explosion; the failure of the Deepwater Horizon blowout preventer; regulatory findings and conclusions; and company practices...
U.S. Chemical Safety Board
The U.S. Chemical Safety and Hazard Investigation Board report is available in multiple volumes that are available on their Macondo Blowout and Explosion page, as well as below for ready reference:
National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling
President Obama established the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling through Executive Order 13543 on May 21, 2010. The Commission was established to examine the relevant facts and circumstances concerning the root causes of the Deepwater Horizon oil disaster and develop options to guard against, and mitigate the impact of, oil spills associated with offshore drilling. This included recommending improvements to federal laws, regulations, and industry practices and organizational or other reforms of Federal agencies or processes necessary to ensure implementing and maintaining those improvements.
A final report on the Commission’s findings was presented to the President on January 12, 2011.
The Oil Spill Commission Action project is an outgrowth of the National Oil Spill Commission, to continue efforts to make offshore oil drilling safer by promoting the implementation of the recommendations of the National Oil Spill Commission. Additional information and National Oil Spill Commission documentation is available through the OSCA website.
Commission resources are as follows (linked below for ready reference and available through the OSCA Resource Center):
BP Incident Investigation Team
The BP Deepwater Horizon Accident Investigation Report (opens in a new window; contents summarized below) was published on September 8, 2010, using evidence that was available at the time and while many of the reports that were previously listed were in process.
In their report, the BP incident investigation team summarized breached barriers with the following graphic (image credit BP; Figure 1 on pages 32 and 181 of the linked BP report):
Transocean Investigation Report
The Transocean Macondo Well Incident Investigation Report is available in two volumes, as linked and summarized below. Additional information is available on Transocean's website by searching "Deepwater Horizon", "Macondo", or similar terms in their site search box.
Macondo Well Incident: Transocean Investigation Report, Volume I (opens in a new window; contents summarized below)
Macondo Well Incident: Transocean Investigation Report, Volume II (opens in a new window; Volume II contains appendices, as listed below)
Republic of the Marshall Islands
The Republic of the Marshall Islands (RMI) was the Flag State Administration of the DEEPWATER HORIZON and published the RMI Investigation Report (opens in a new window) on August 17, 2011. The report contents are summarized as follows:
AUGER Lifeboat No. 6
This incident occurred on FPS AUGER, a Tension Leg Platform (TLP) at Garden Banks Block 426 in the Gulf of Mexico, on June 30, 2019 and resulted in the untimely deaths of two personnel and injury to a third person. The incident occurred when Lifeboat 6 released from the fall cables during recovery after a routine launch and perceived U.S. Coast Guard requirements. Our condolences go to the families of those crewmembers that lost their lives during this incident.
The USCG formal investigation has been completed and endorsed by the District Commander, Coast Guard District Eight, but is still under review for Commandant actions at USCG Headquarters. The information on this page is associated with USCG Safety Alert 03-20 that was issued as a result of findings/concerns during the investigation, until such time that the Report of Investigation for this incident is made available to the public.
Safety Alert Summary
Safety Alert 03-20 was published on February 5, 2020, after observations and testing revealed that a damaged/compromised hook control cable could fail in a manner that would allow a hook to open, essentially defeating the safety features that are incorporated into the design of a lifeboat release gear system. Prior failures with these types of control cables were assumed to be 1) a seized cable or 2) a severed cable. Shell Offshore, Inc. and USCG investigation team members observed that another failure mode was possible, as summarized in the safety alert:
"During post-incident laboratory testing the Coast Guard observed that if a control cable, similar to that shown in the image above, is damaged all the way through the outer layers, leaving the traveling inner member exposed, forces applied directly on the separated outer layers can cause the traveling inner member to pull on each of its ends. As the separated outer layers pull apart, the cable’s end rod at the hook can move, which in turn can rotate the locking shaft inside the hook. If the locking shaft rotates enough, the hook can release, even without an operator touching the release handle or overriding the interlocks. The Coast Guard has no indication that a damaged control cable alone can cause a hook to release or open on-load. However, the Coast Guard believes that damaged control cables pose a significant safety risk and should be replaced before attempting to launch a boat that incorporates control cables into the on-load release capability of a hook release system."
Presentation and Videos
Safety Alert 03-20 and the observations from CG-testing were presented during the September 30, 2020 National Offshore Safety Advisory Committee (NOSAC) meeting (video teleconference). The presentation and individual videos (mp4 format) are available below. Note that the presentation is a large file size (30mb), as the videos are embedded within the presentation, but can also be downloaded separately. Microsoft PowerPoint or a compatible viewer will be needed to view the presentation.
Discussion of Observations and Findings
Please note that testing was conducted on Schat-Harding LHR-series release gear. As such, the descriptions of components and operation relate to that make and series of release gear. Other manufacturer's release gear designs, functions and component terminology could vary, but the control cable is the area of focus in these findings.
Generally, the system works in the following manner:
When closing or resetting a hook, an operator positioned at the release unit pulls up on the safety lock and pushes forward on the control handle, locking it into place. Consequently, the end rod on the hook extends. This extension causes the hook's locking shaft to rotate to the closed or locked position. When opening the hook, the opposite actions and forces apply.
A previously unknown vulnerability in the system was identified during the course of the investigation that was referenced in Safety Alert 03-20: if all three layers of the conduit of a hook cable separate or break during a reset, the locking shaft may not return to the fully-closed position. Rather, the locking shaft may come to rest at an "almost-open" position (see the various positions on the following graphics). In such a position, the hooks can support the weight of the boat and its occupants during retrieval. However, testing has revealed that an additional load can cause the locking shaft to rotate to the open position, releasing the hook.
Release Mechanism Arrangement
A typical dual-fall/hook release mechanism is comprised of two hooks, a hook release unit (located inside the lifeboat adjacent to the helm), a hydrostat unit, and three control (push-pull) cables. One control cable connects the hook release unit to the aft hook, the second control cable connects the release unit to the forward hook, and the third control cable connects the release unit to the hydrostat unit.
This graphic shows the positions of the control cable and the hook when the release unit handle is in the closed, or reset, position.
This graphic depicts the actions of the control cable and the hook when the release unit handle is moved into the open, or released, position.
Closed/Reset Position with compromised cover and steel layers
With the conduit cover and steel reinforcement compromised but the liner still intact, the system continues to function. In this condition, the liner is subjected to compression and tension forces that correspond to the open and close motions of the release handle that is transmitted through the control cable.
Closed/Reset Position with separated conduit (broken liner)
The conduit tends to separate after the liner breaks. This separation causes the conduit to lengthen and results in the inner member moving the locking shaft arm toward the open position. During testing, it was observed that the:
Effects of Increasing Load with a separated conduit
Testing confirmed that the locking shaft can be in a partially-closed position that will support the weight of the boat and occupants, but can rotate to the open position with an increasing load/additional weight (such as the additional load that can be imparted to the hooks as a boat is pulled against the davit bumpers).
Close/Reset Position with separated conduit after additional cycling
Additional cycling (opening and closing) of the release handle during testing showed that the cable conduit would separate before any rotation was transferred to the locking shaft. This condition leaves the hook in an open position that will not support any weight.
Based on these observations, the USCG strongly recommends the following in Safety Alert 03-20:
The safety alert also noted that: