Sinking of anchor handler off Scotland prompts review of training and vessel design

Bourbon Dolphin was almost brand new when it capsized and then sank in April while helping to move an oil rig. (Bourbon Offshore)

The anchor-handling tug was listing 90° toward port. Two engines had just failed. Other crewmen were grabbing life jackets.

Second Mate Geir Tore Syversen decided it was time to escape from the bridge.
“I’m going now,” Syversen said, as he tried to climb out of his chair. But Syversen’s captain, Oddne Arve Remøy, shouted one last instruction to the 21-year-old second mate. In an attempt to avert an almost-unthinkable sinking of the state-of-the-art anchor handler Bourbon Dolphin, the captain ordered Syversen to press the emergency release button on the winch.

Remøy’s plan was to ease the tension from the almost 6,000 feet of iron chain that threatened to capsize their brand-new tug, imperiling the lives of the 15 crew.
The result was not what the seamen expected. The whole chain didn’t rush out and drop harmlessly to the bottom of the North Atlantic. Instead, the device let out chain at a rate of only 39 feet per minute.

Seconds later, Bourbon Dolphin did capsize. Eight of the 15 crew were killed in the April 12 accident off the Shetland Islands. It was the first-ever fatal casualty involving a Norwegian anchor-handling operation. The incident has prompted Norway’s offshore supply industry to rethink its safety standards, crew training and ship design.

The Norway-flagged Bourbon Dolphin found itself in trouble 75 nautical miles northwest of the Shetlands, while helping to move the oil rig Transocean Rather about two nautical miles. An assisting tug, Highland Valour, couldn’t keep its grapple grip on the anchor chain.

Bourbon Dolphin never should have been the lead vessel on such a maneuver, its operator and regulators said afterward. While Bourbon Dolphin struggled with the anchor chain, tension on its winch rose to at least 330 tons. The charterer had specified that the 2,985-gross-ton tug could operate safely only with up to 240 tons of tension on the winch.

After the accident and rescue operation, which occurred in international waters, a special Norwegian judicial panel immediately began investigating the cause. Even before any conclusions were drawn, the Norwegian Maritime Directorate issued a series of “immediate measures” for the industry. The May 10 announcement identified these initiatives:

• Ship owners will be required to prepare additional stability calculations for their tugboats. The new measurements will identify limitations on bank angle and broadwise tension on the anchor-handling wire or chain.

• The industry needs a separate definition of bollard pull in anchor-handling operations. Crews must realize that the use of both winches and thrusters will limit how much power remains for bollard pull.

• Crews on every anchor-handling vessel must be instructed on how the winches’ emergency release system works and when it should be used.

• The industry must establish procedures to govern tandem anchor-handling operations.
The problem of bank angle and broadwise tension is receiving more attention throughout the towing industry, said Capt. Gregory Brooks, a tug safety consultant with Towing Solutions Inc. of Spring Hill, Fla.

“It’s similar to how tugs are capsized in towing operations,” Brooks said. “Anchor handlers are kind of the extreme case because they handle very, very heavy weight, but we have the same effect when we are towing barges on a short hawser. You have the same sort of towline forces out at an angle.”

Trond Myklebust, managing director of Bourbon Offshore Norway, said a “series of events” — not any faulty equipment — doomed Bourbon Dolphin. Bourbon Offshore was the owner and operator of the vessel.

According to crew testimony at an April 25 judicial inquiry, Highland Valour tried and failed at least four times to grip the anchor chain with its grapple. When it finally did manage to grab hold of the chain, it fell off the grapple, causing the tension to soar on Bourbon Dolphin.

“We are quite confident that nothing was wrong with the boat,” Myklebust said of Bourbon Dolphin during an interview with Professional Mariner. “That boat should not be the lead anchor handler. Unfortunately, the assisting tug was not able to assist. It’s easy to say now that the captain should have stopped the operation.”

Norway’s Ulstein Group constructed Bourbon Dolphin. Bourbon Offshore took delivery of the 247-foot vessel in September 2006.

The nation’s shipping establishment was shocked at reports that Bourbon Dolphin capsized, said Sigurd Gude, deputy director general of the Norwegian Maritime Directorate. The vessel eventually sank.

“Most people in the industry had an impression that these supply vessels are very, very good in terms of stability, and this accident showed that it’s the other way around,” Gude told Professional Mariner.

Seven Norwegians and one Dane were killed. Among the dead were Remøy, the captain, who was 44, and his 14-year-old son, David, who was along on sea training.
The other Norwegians who died were Bjarte Grimstad, 37; Kjetil Rune Våge, 31; Frank Nygørd, 42; Ronny Emblem, 25, and Tor Karl Sandø¸, 54. The Dane was Søren Kroer, 27.

Syversen, the second mate, plunged into the 37° water before he had time to grab a life jacket. At first, he held onto another seaman in the water who had a life jacket. A raft drifted toward the men, and they climbed aboard. Man-overboard boats picked up the other survivors.

Syversen and two other survivors testified at Norway’s Department of Justice maritime inquiry April 25 in a courtroom in the coastal city of Alesund. The witnesses gave this account of what happened after Bourbon Dolphin and Highland Valour began their tandem assignment at around 1500 hours on April 12:

The rig’s 3.5-inch anchor chain was already secured to Bourbon Dolphin’s 2.9-inch chain with a shark jaw. Highland Valour was about 650 feet behind Bourbon Dolphin’s stern when Highland Valour grabbed the anchor chain with a grapple.

Bourbon Dolphin ran out chain from its chain well for two to three minutes. Suddenly Highland Valour lost its grip on the chain and drifted at high speed toward Bourbon Dolphin’s stern, almost causing a collision. Bourbon Dolphin’s chief mate averted the collision by giving full throttle ahead.

As Highland Valour was attempting to hook the chain again, the tension aboard Bourbon Dolphin was 180 tons. Highland Valour failed in four attempts to hook the chain up. While waiting, Bourbon Dolphin used full thruster capacity to maintain its position in the 32-knot wind and the waves of almost 10 feet. The current was around 2 knots.

At 1545 the chief engineer requested a reduction in the thrusters because of overheating. The chief mate denied the request, explaining that the vessel had drifted too far away from the anchor position.

Highland Valour succeeded on its fifth attempt to grasp the chain. The towing master on the rig and Bourbon Dolphin’s chief mate then told Highland Valour to move in a northwesterly direction toward Bourbon Dolphin’s port quarter. Highland Valour instead moved to the southeast for about 30 seconds, sending the chain at a wrong angle through the towing pins and pulling Bourbon Dolphin toward port.

According to Syversen, Bourbon Dolphin’s captain then came to the bridge, radioed Highland Valour and “asked if they knew the difference between north, west, south and east.” Highland Valour corrected the direction.

At 1650, Bourbon Dolphin’s chief engineer called the bridge and again asked for a reduction in the thrusters, warning that he would otherwise need to cut engines. The vessel maintained a slight tilt toward port. Highland Valour then lost its grip on the chain yet again.

“The rig asked, ‘What are you going to do to get out of the situation you have placed the Bourbon Dolphin in?’” Syversen testified. “The Highland Valour answered, ‘We will try to grapple again.’”

At 1655, the tension was up to 290 tons. Bourbon Dolphin was moving toward port, while an officer shifted ballast to starboard.

By 1700, tension had reached 330 tons. The towing master on the rig proposed that Bourbon Dolphin lower the inner starboard towing pin. The first mate tried to force down the handle on the control panel to lower the pin, but the high tension made it impossible.
The captain changed course to starboard, causing enough of a drop in tension to allow the chief mate to press down the inner pin. The chain then flew over the outer towing pin and didn’t pass over the cargo rail. A list to port resulted.

Bourbon Dolphin drifted at high speed toward port. Parts of the cargo deck disappeared underwater. Both main starboard engines stopped. The vessel’s list was 90°.

That’s when the captain ordered Syversen to press the winch’s emergency release button. Bourbon Dolphin capsized anyway.

Though the judicial inquiry won’t be finished for months, Bourbon Offshore has already begun modifying its crew manuals for its four remaining anchor-handling tugs. Bjorn Remøy, the company’s operations director, said the manual rewrite will address the issues of bank angle and broadwise tension and proper use of the emergency release system. New rules for tandem operations are also being implemented.

“You have to verify if your vessel can take all the forces alone … if the other vessel fails,”
Remøy said. “Otherwise, no operation will be performed.”

Myklebust said the industry has been switching to using lighter-weight fiber lines instead of iron chains.

The industry has learned two other lessons from the Bourbon Dolphin incident, said Gude, with the Norwegian Maritime Directorate.

First, future anchor-handling tugs probably will be built with a wider beam. Bourbon Dolphin’s beam was 17 meters, or about 56 feet. Inclination should not be greater than 10° on either side, he said.

“If you widen the beam of that vessel by 3 meters, you will have a very stable vessel,” Gude said.

Second, Gude said, the “emergency release” system is misnamed. That mechanism is meant to reduce tension if a power failure occurs during a maneuver, such as coaxing the anchor to dig itself into the seabed.

“The most important thing is to understand what happens when you push that button,” he said. “‘Tension release’ is probably a much better word, because you shouldn’t use it in an emergency.”

Brooks, the tug safety consultant, said marine-training simulators soon will probably include broadwise tension models. A common scenario is a barge in tow surging side to side as speed picks up. “It’s an area where we don’t do enough instruction,” Brooks said. “It’s coming.”

Norway’s maritime inquiry continued in June. The regulators and the industry will be working throughout 2007 to determine the new operating standards.

In the meantime, Bourbon Offshore is assisting the families of the victims. The company has established a foundation to fund their children’s education.

By Professional Mariner Staff