Handling the latest in ship docking tugs

The low hull and trunk cabin with the wheelhouse set back lend the tug Charles H. Cates VI a sense of power and determination. Built to a Robert Allan Ltd. design in 1980, the twin-screw tug boasts 1,600 hp and a bollard pull of 56,000 pounds. There was a time that this was a powerful tug capable of docking any ship that visited British Columbia’s Port of Vancouver. But ships have grown, and at the docking of a coal ship in September 2009 Cates VI was relegated to the job of line handler.

A view from the bow of the tugboat Seaspan Resolution, while the vessel assists the 890-foot coal carrier Amagisan at Vancouver Harbour. (Alan Haig-Brown photo)

Doing the real work of pushing the big ship up to the dock were the 4,000-hp z-drive tug Seaspan Discovery and the new 6,000-hp Seaspan Resolution. Discovery, built in 1984, delivers 133,000 pounds of bollard pull, while Resolution, built in 2009 with 50 percent more horsepower, delivers 165,000 pounds of bollard pull. But as Capt. Michael Harris explains, horsepower and bollard pull are only part of the story.

“This is the first tug in B.C. with a skeg forward,” Harris explained to me when I boarded that morning. In his 25 years as master, Harris has worked everything from single-screw tugs to z-drives, but this new boat was something else. “New regulations will require more escorts for tankers in Canadian waters,” he explained.

Deck hand Ed Dillon, who has 40 years of experience on tugboats, is part of Seaspan Resolution’s crew. (Alan Haig-Brown photo)

The greatest challenge to an escort tug is to be able to take control of a tanker in the event that it loses steerage or propulsion power. While a number of Robert Allan-designed tugs have been built with skegs, Resolution is the first on Canada’s west coast. The Port of Vancouver is entered through the First Narrows under Lions Gate Bridge, but the principal refineries are on through the Second Narrows. The skeg will allow Resolution to work the indirect mode that places the tug and its skeg at an angle to the direction of the ship’s turn in an emergency to stop the turn and hold the ship on course.

Capt. Angelo Pignatelli pilots Seaspan Resolution alongside the bulk carrier Amagisan. The 6,000-hp tug is British Columbia’s first with a skeg forward. (Alan Haig-Brown photo)

For now the big new tug is stationed at Deltaport, a combination container and coal port, south of the Port of Vancouver. Crews on Seaspan’s ship-handling tugs work a 10-to-10 day. This allows them to commute from home each day. The unusual time was developed sometime ago for the Vancouver harbor tugs as it avoided crew changes during the busy morning hours when most vessels want to be shifted on or off the loading docks. Each 12-hour watch on Resolution includes a deck hand and engineer along with the captain. On the morning I boarded Resolution, Harris was replaced at 1000 by Capt. Angelo Pignatelli.

He arrived just in time to ask Engineer Dave Van Herwaarden to fire up the two big 12-cylinder EMD 710 main engines. Deltaport is expanding to add a third container berth to the two existing berths and the two coal berths. The ship to be undocked this morning was Azul Fortuna. The 981-foot-by-164-foot bulker was moored across the end of the terminal. Loaded with coal, it had a draft of 52 feet. This was a big, heavy ship with a lot of draft. Deck hand Ed Dillon went down to the bow where Pignatelli payed out the 3.5-inch synthetic hawser from the electric Burrard Iron Works single drum winch. Dillon flaked it out on the deck, and it was ready to be pulled up through the ship’s fairlead.

Engineer Dave Van Herwaarden in Seaspan Resolution’s engine room, with one of its two 12-cylinder two-stroke EMD 710 engines with carbon fiber shafts linked to Hitachi gears, and 1.2:1 reduction ratio for Niigata drives. (Alan Haig-Brown photo)

The BC Coast pilot on the ship called Pignatelli on the VHF to tell him that the ship’s bollard could handle only 78 tons, which was very close to the maximum bollard pull of Resolution. Explaining that it wouldn’t be a problem in the relatively calm waters and with a straight pull off the dock, Pignatelli said in a heavy swell the bollard pull can vary. But first the pilot asked for “easy push to dock” while the lines were let go. The tachometer on the tug showed 680 revolutions per minute of the engines’ 900-rpm maximum. As Resolution pushed easy on the ship’s starboard shoulder, the 4,000-hp Seaspan Discovery pushed on the stern quarter.

After about 10 minutes of this, the pilot asked for both tugs to stop. Pignatelli cut the throttles so that the tachs dropped to their 400 rpm idle speed. Leaving the clutches engaged, he adjusted the z-drive legs so that the boat held its place in the tide without pushing on the ship’s hull. With the lines off the dock and both tugs with their hawsers up to the ship, the pilot asked Resolution to pull back. Two minutes later he asked Discovery to also pull full back. Pignatelli ran out about 200 feet of the 1,000 feet that he has on the winch and ran the rpm up to the full 900.

“You want to be far enough off that your wash doesn’t push up against the ship,” he explained. The strain gauge on the overhead climbed to 75 tons and held there. Five minutes later, the ship, even with its deep draft, was clear of the dock. Discovery moved around and up the port side to push on the bow to help Resolution turn the ship out, so that it could head to sea at an angle to the dock face. Minutes later the pilot said, “Resolution, you can shorten your line.” By 1036, less than a half-hour after putting the first line up, Resolution had its line back and the ship was beginning its 16-day passage to Fukuyama, Japan.

At 1130, out in the Strait of Georgia shipping lane, the empty bulker Amagisan appeared out of the mist, having come around from a nearby anchorage to take the place of Azul Fortuna under the coal loader. As we waited for the new ship to approach, Pignatelli reminisced about learning to handle a single-screw tug in the Fraser River currents.

“You have to get a boat from Point A to Point B. It doesn’t matter if it is a little single-screw tug or a tractor like this one,” he said. “A tractor tug will not make you a good boat handler if you can’t judge distance and speed. When things go wrong and if the pilot is getting excited, you have to be able to keep it all together. If the pilot is yelling for full astern, I have to get some strain on a slack line before I give him full astern or we will pop the line and be no good to him.”

As the bulk of Amagisan riding high on her marks neared the waiting tugs, her pilot asked Resolution to put a line up to the starboard shoulder and Discovery to do the same for the stern quarter. As with the undocking of the previous ship, the run in for the new ship required only a little pull from the tug on the starboard shoulder. The ship’s pilot cautioned Pignatelli that the ship’s forward bollard was certified for 60 tons and the fairlead for only 40 tons. By 1150 the sailors had put the line up through a more substantial looking lead further forward. The beginning of the ebb was setting across the pier face with just a little set toward the pier to aid the ship into place. The two tugs working with the pilot made one of those classy smooth landings that indicate years of experience, teamwork and skilled boat handling. There was no need to exceed even the lower tonnage rating on the fairlead.

The Burrard Iron Works winch has a built-in render-recover capability that can be adjusted to 5, 20 or 40 tons for use when a light touch is required. By simply pushing one of three buttons on his control panel, the captain can select one of the three options so that if the strain exceeds the set value, the brake will let line pay out and then recover it when the strain is less than the set amount. “We are more likely to use this on one of the old grain ships,” noted Pignatelli in reference to the tug’s power and the lighter bollards on some of the older bulkers. With the ship in place, the pilot asked the two tugs to hold it to the pier while the dock crew got the spring line up. The ship had been at anchor to await the pier space. Now the washers were still pouring cascades of water down the hawsepipes and over the anchors to the dismay of the crew on Cates VI that was waiting to get in under the bow to take the four bow-lines over to the mooring buoy. Getting the lines up fore and aft took longer than bringing the ship into the pier. So Resolution and Discovery kept pushing easy on Amagisan’s side until 1245 when Dillon left the wheelhouse to go back to the foredeck to retrieve the line as it was lowered past the ship’s draft marks, which showed at the 26-foot mark.

From the time he left the wheelhouse for the foredeck, Dillon was always in clear sight of the captain. The wheelhouse is set back on the main deck cabin so that the angle of view is clear to the winch drum, staple and the bulwarks. When not in use, the center-mounted flat-screen monitor for one of the radars can be bent out of the line of sight. With virtually all the work done off the bow, this is an very safe vessel.

With the task of swapping a loaded vessel for an empty coal ship, Resolution and Discovery headed back to their dock, which is tucked in behind the expanded container terminal. Entering the confined area with other vessels nearby, Pignatelli reduced the engine speed to idle and then used the slipping clutches to further reduce the prop wash that can be caused when redirecting the drives. Cates VI went off to pick up a construction barge to be taken back to Vancouver Harbour, and I had a chance to visit the engine room on Resolution with Engineer Van Herwaarden. It is an interesting setup. The two EMDs are soft mounted with an approximately six-foot carbon fiber shaft linking them to big solid mounted Hitachi gears. The carbon fiber shafts have enough flex to allow the linking of the soft and hard mounted components. The offset gears have ratios of only 1.2:1 in order to reduce the 900 rpm to the lower rpm required for the Niigata z-drives. The combination results in an extremely quiet boat. The two-cycle EMD engines with cam operated valves and electronic fuel injectors are classed as Tier II compliant. Seaspan Discovery had Niigata engines and drives, but Seaspan has a large number of EMDs in the fleet which aided the choice for the new boat.

A pair of big 29-inch ducts blow air into the engine room. These are fitted with large filters to prevent coal dust from being sucked into the engine room. They are also tied into the engine’s computer systems so that they increase their speed with that of the engines. The engines are cooled by raw water heat exchangers rather than keel coolers. A “spill tank” is built into the hull so that the vents and overflow from the main tanks will come into this secondary tank rather than onto the deck. Two John Deere-powered generator sets are in the engine room. The smaller 99-kW set is for the tug’s general electrical supply while the larger 250-kW set provides power for the winch motor through a Balder frequency drive controller. With 20 years on a variety of tugs, Van Herwaarden is delighted to find himself surrounded by such up-to-date and complex equipment.

By Professional Mariner Staff