A rigger standing on the hull surveys the scene as the capsized barge begins to rotate.
But that wasn’t Hughes’ first salvage. Having started at Rivtow in 1980 and moving to the maintenance department in 1987, he learned and lived by the B.C. towboat industry’s maxim: “Make do.”
The B.C. towboat industry has evolved a routine means of righting flipped flat-deck barges by a simple process of power buckling with the aid of anchors and tugs. When the Washington Marine Group’s self-loading and self-dumping log barge Seaspan Rigger flipped in Howe Sound, north of Vancouver, on Oct. 19, 2002, everyone knew this would be no routine salvage job.
With a 15,000-ton cargo capacity, Rigger is 396 feet long with an 88-foot beam and a 25-foot molded depth. But what made this a real challenge was the use of two cranes to load the logs on the barge. With a 70-ton lifting capacity at a 90-foot radius, the two cranes weighed 240 tons each and were mounted on 50-foot pedestals.
Log barges of this type are towed to up-coast logging sites, where their cranes are used to load bundles of logs and stack them across the deck and against large fore and aft bulkheads. The barges carry their own small tugs that shepherd the logs being loaded from the water. After being towed south to sorting grounds near Vancouver, two large tanks in the starboard side of the hull are flooded until the list on the barge is such that the 15,000 tons of logs slide off into the water.
Barges like Rigger are designed so that this simple operation works well. Yet these barges are stable enough to travel back up coast in the light condition and handle the great leveraged weights of log loading. Rigger’s vertical center of gravity is just a few inches below deck level, but her great beam and full chine give her excellent initial stability. Built in 1980, the barge has hauled hundreds of loads without mishap. What went wrong on that Saturday in October is still unresolved, but when the logs were dumped, rather than popping back onto an even keel, the big barge just kept on rolling. When things settled down, the shocked crews of attending tugs saw only the huge, flat bottom.
It became apparent that the barge was not sinking. When it went over, the booms of the two cranes embedded their tips in the bottom, effectively anchoring the barge in place. Don MacKenzie’s 65-foot tug Kinnaird was chartered to stand by the hull and monitor the oil-spill boom that had been deployed to protect the waters from oil that leaked from the crane and various pump engines onboard.
Within days, Seaspan put the salvage job to tenders. Among the eight bidders, several were from large salvage companies with the know-how, but Rivtow-Smit had the advantage of local equipment and expertise. It could also claim a dedicated salvage engineering office in Rotterdam, along with specialized engineers and crews, some of whom had recently added the salvage of the Russian submarine Kursk to a long list of successes.
The Rivtow-Smit bid was accepted on Nov. 27, over a month after the barge had flipped and the clock started running. Salvage gear, including huge wires, shackles, blocks, and dozens of other bits and pieces that could not be obtained locally, were assembled and loaded into containers in the Netherlands. While these were being shipped across the Atlantic and hauled by train across Canada, engineering work progressed at the site. On Dec. 6, divers went down and, using explosives, blew the booms off the cranes to free the barge from the bottom. Two of Seaspan’s tugs then moved the hull 10 miles to Long Bay on Gambier Island in Howe Sound, and Rivtow-Smit took care and custody at the location.
Long Bay was chosen for the operation because of its narrow but deep north-south orientation. Facing away from the head of the mountainous inlet, it provided some shelter from powerful outflow winds that can pour out of the mountain passes in winter. At the same time, it was sheltered from the prevailing southeasters by Bowen Island that sits like a loose plug in the mouth of Howe Sound. Most importantly, the steep granite shores of the bay are only 2,575 feet apart. The salvage engineers ascertained that having solid land anchors on both ends of the power buckle would be far more effective than sea-bottom anchors.
|
The overturned hull was anchored fore and aft nearer to the eastern shore of the bay. With the cranes hanging down in the water, Rigger was drawing 115 feet with an air draft of only 19 feet. As stable as a sailboat with no mast.
|
One of the first tasks was to bore holes 40 to 50 feet into the rock walls of the bay to anchor the operation. Four lines were shackled to pad eyes, each with four bolts sunk into and grouted to the rock face, for a total of 32 of these deep holes to be drilled.
On the eastern side, drilling was done from a barge. To each of the four eyes on this side, 984 feet of approximately 5-inch Dyneema 360-ton test lines were shackled. The other end of each of these lines was shackled to a pair of harnesses that led under the barge to a total of 16 hold-back bollards that were welded to the bottom of the barge just in from the starboard, or western, side. At the same time, wire ropes were fastened to 16 strong points on the starboard side of the barge. These progressed through similar harness to join four 738-foot-long, 5-inch wire ropes that passed under that barge to emerge from the water on the port, or eastern, side of the barge before passing over the bottom.
The long end of these huge wires extended across the bay to a winch barge, the 300-by-50-foot Capt. Vernon, where they passed through a pair of equalizers shackled to huge blocks. Between the log barge and the winch barge, a 165-foot barge served as a float to minimize the weight and droop of the heavy wires.
From the western end of the winch barge, heavy wires extended about 492 feet across the decks of two additional barges and a stretch of water, to be shackled to pad eyes set into the rock on that shore. On Capt. Vernon, which was anchored on four points, two 50-ton winches faced away from the log barge. From their drums, smaller 1.57-inch wires led into a pair of blue-painted multi-sheaved blocks at the western end of the barge that matched blocks at the eastern end with the wires that led to the log barge.
The multiple sheaves in these blocks provided for 10 parts of multiplying winch power and provided nearly the whole of the 300-foot barge length of take-up.
Countless additional details were attended to, such as turning the inverted cranes on their pedestals so that their counterbalance weights would not cause violent swings that could damage the valuable pieces of equipment as the barge was being righted. This task was achieved by having divers go down and fix hydraulic hoses to the winch mechanism from a portable hydraulic pump on a barge above.
This was not a wreck removal job, Hughes explained. “Seaspan wanted their barge back, with the cranes intact.”
The log barge’s two tipping tanks extend down the starboard side and 25 feet in from the side shell. The salvors cut two 8-inch valves into each tank alongside their inboard longitudinal bulkheads. Valves for 4-inch air hoses were cut into the side shell of each tipping tank. The tipping tanks were then pumped full with about 200,000 cubic feet, or 5,700 metric tons, of water. This gave the inverted barge a 10° list.
At first light on Jan. 11, just one month after taking care and custody of Seaspan Rigger, the salvors were ready. Dark clouds hung low over the bay, but there was very little wind. Divers made an inspection swim of the underwater rigging. The rigging crew crawled over the bottom of the barge, making one last check. The four water-ingress valves on the tipping tanks were closed.
The diesels on the big winches were fired up. The wires started to wind onto their drums. The blocks nearest the log barge inched toward their mates at the other end of the winch barge. As the slack came out of the big wires, they rose from the water as their weight added a couple of degrees to the list on the log barge. By 1300, load monitors mounted on the winch barge showed 150 tons of pull on the wires to the barge with the slack out of the lines. The rigging was designed to withstand 800 tons of pull.
Then the winches were dogged down, and the riggers went back to scrambling over the log barge bottom. With so much time and expense (the job is reputed to have cost in the millions of dollars), nothing was being left to chance. Finally they climbed back into the small boats and left — all, that is, except the Dutch head rigger, who walked up to the barge’s high side and sat down on the chine.
The winch drums revolved slowly, and the two huge blue blocks with their multiple sheaves began to inch toward each other again. As Rigger’s massive cranes cleared the water, they added their leveraged weight to the strain.
By 1400 the bottom of Rigger was inclined at about 45°, and the load monitors showed 672 tons of total pulling forces. Equating this with the 150-ton static bollard pull on a 10,000-hp tug like Crowley’s Alert or the 57-ton bollard pull on a 4,000-hp docking tug, it is easy to see why the salvors chose a location where they could anchor both ends of the operation to solid rock shores.
As the winches continued to pull the two blocks together, observers questioned if the barge would get up on its beam ends before the two blue blocks touched. But by 1700 the winch had brought the barge to 90°, and the pull on the strain meters had eased back to 500 tons. As the barge passed the 90° mark, some 20 feet still separated the two blocks, but the barge was not about to flop back on its bottom. The winches kept their slow pace until 1745, when the winches came block to block and the strain meter showed 372 tons of force.
Rigger was a good 10° past the vertical. However, the 5,700 metric tons of water in the tipping tanks combined with the 480-ton weight of the two cranes set out on their 50-foot pedestals to hold the barge suspended above the waters of the bay.
In the cloudy northern winter night, the operation was lit by barge-mounted floodlights and by the spotlights of the stand-by vessels. The spotlights of the tugs picked up the reflective tape on the Dutch rigger’s work vest as he perched on the barge’s stern quarter, 50 feet above the water. By radio he reported to Hughes that all was looking good from his position. Apart from the cold, watchers wondered how he would manage if the barge suddenly righted itself.
|
But first the dive barge had to be brought back in under the overhanging barge, and at 1830, a diver went down to affix a pair of 4-inch air hoses to the valves in the tipping tanks. With this done by 1920, the air was turned on to pump out the 800 tons of water in the triangular space formed by the inclination of the tank’s longitudinal bulkhead that was, at the moment, the tank top. The 800 tons of water were pumped out by 2100.
The barge rose up on its side from the water so that the curve of the starboard bow was showing, but still there were several feet of water-filled barge acting as keel ballast and still the weight of the cranes. Pull on the strain meters was down from 372 to 240 tons, and it was clear the barge was not going to come down yet.
Now the salvors brought in their alternate plan. Diver Ted Hill was sent back down to cut holes in the tipping tanks near the barge chine. This would allow the air pressure to force as much of the remaining 4,900 tons of water out of the tipping tanks as required.
It was becoming a long day for Hill under the barge and the rigger on top. If Hughes and the rest of the salvage team were feeling any stress as the climax of their multimillion-dollar job approached, their voices on the radios didn’t betray it.
At 2230 the diver had finished his work, and the air was turned on again. In the spotlights, the starboard side of the barge resumed its barely perceptible rise from the water. The rigger was now perched on the stern quarter a good 65 feet out of the water, but still a water-laden 23 feet of the barge’s beam remained in the water. The barge bottom retained its inclination of about 10° past vertical.
By 2240 the strain gauges read 213 tons, two feet of belly were showing in the big wires running from Rigger to the winch barge. At 2300 Hughes came on the phone to caution the crews to stay clear of the lines that would surge when the barge finally came down.
At 2305 the strain gauge reading had dropped to 193 tons. It seemed that nearly the whole 88-foot beam of the log barge was out of the water. The barge name and port of registry are painted on the starboard half of the stern. At 2330 the “R” of Seaspan Rigger was clear of the water, as was the second “v” in Vancouver.
By now the Dutch rigger had been on the barge for over 10 hours. Something had to give. And at 2346, it did. There was a loud bang from the barge hull. And then the barge swung down the last 80° of the 180° turn she had started that morning.
Seen from the stern in the floodlights from the surrounding boats, the side finally came back to the water, as the port stern quarter skeg plunged into the water’s dark surface like a slasher’s knife, sending a great splashing wave toward the winch barge. Then the skeg rebounded and plunged again. Finally, the barge came to rest with a 10° starboard list caused by the remaining water in the tipping tanks.
It was a spectacular splash to cap a long day of anticipation but, more importantly, to honor nearly three months of planning and work. The Dutch rigger, who had spent the day sitting atop the barge and then rode it, Rambo-like, to a standstill, had only one comment to the men who picked him up in a skiff. “Cold!” he shuddered.
Some, like salvage master Hughes, might call the job little more than routine, but one observer, with a long maritime career on the Pacific Coast, said of the sight, “That was a once-in-a-lifetime experience.”
