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British Columbia’s new cable ferry always on its moorings

Nov 30, 2016 11:32 AM
Baynes Sound Connector arrives at the Buckley Bay Terminal on Vancouver Island.

Baynes Sound Connector arrives at the Buckley Bay Terminal on Vancouver Island.

“This is not a regular ferry, this is not a regular ferry.” BC Ferries project manager Mark Nemeth repeated this mantra to himself in the early stages of building Baynes Sound Connector at Seaspan’s Vancouver Shipyards. As a cable vessel it isn’t unique, but at 258 feet it is one of the largest of its type. It also operates on the longest cable ferry run in the world.

Baynes Sound is a narrow channel between 12-mile-long Denman Island and the east coast of Vancouver Island. For years, a conventional ro-ro ferry served the run of about 1.2 miles. When it came time for a new ferry, officials noted that the channel is about 195 feet at its deepest point and generally has a sandy bottom, which would allow cables to lie on the sea floor without damaging the lines or the environment. While it is subject to strong winter southeast winds, the reach is not so long that wave heights become excessive.

Baynes Sound Connector was launched at the Vancouver Shipyards in 2015. Following finishing work alongside the shipyard, the boat was towed to the site where the cables already had been installed. It went into service early in 2016 after a period of testing and crew training.

The 258-foot vessel, built by Seaspan’s Vancouver Shipyards, operates by moving along more than a mile of cable stretched between Denman Island and Vancouver Island.

Nemeth had taken early retirement as an engineering superintendent with the BC Ferry Corp., but he went back to work to join the vessel replacement team for construction of the boat. Of retirement he said, “We drove all over North America in our mobile home but when I came back home to BC, I needed something to do.”

He enjoys his new work and is particularly enthusiastic about Baynes Sound Connector. Somewhere between a barge and a boat, the ferry operates by pulling itself along a 6,233-foot-long cable that is 1.6 inches in diameter. Two guide cables of the same diameter are anchored in massive concrete piers and then pass through sheaves under the ferry’s sponsons. Top speed is 8.5 knots.

The cable mechanism is the heart of the boat. The main deckhouse, which equally divides the ferry’s four vehicle lanes, is set in the middle of the boat. An area of passenger seating is set at one end of this deckhouse. Amidships in the long narrow house are the two hydraulically driven bull wheels that pull the ferry along the cable. They are each about 6 feet in diameter and have a single groove for the cable. As the bull wheels turn at up to 54 rpm, the cable enters one end of the boat, passes under the first wheel and around the second wheel. It then passes around the first wheel and under both wheels to exit the other end of the boat. This setup provides maximum friction between the wheels and the cable while utilizing dual hydraulic motors for power.

A green light indicates that the ferry is in the terminal and it is safe for other vessels to cross the underwater cables. A red light warns that the ferry is en route.

The hydraulic drives for the wheels are located on the other side of a fore and aft bulkhead in their own space with short shafts passing through the wall. Attached to each drive is a powerful brake that can be used for emergency stops when underway. The brakes also are used to lock the ferry into a terminal at night — no additional mooring is required.

Power for the hydraulic motors is provided by two Caterpillar C18 IMO Tier II diesels each turning a 120-KVA alternator in addition to the hydraulic pump. Each 499-hp engine provides all the power for the hydraulics as well as meeting the electrical requirements of the vessel’s heating and lighting. Each engine drives a separate hydraulic motor for complete redundancy. If one engine should fail while underway, a 20-second delay would be followed by the second engine starting and providing power.

Normal power for a conventional ferry of this size, capable of carrying 50 cars and 150 passengers, would be in the range of 1,800 hp. That is more than three times the power required to pull the ferry along a cable moored to the shore. Because hydraulic motors drive the bull wheels, the engine operates at a continuous rpm. This, together with the lower horsepower, results in fuel savings of 50 percent or more and reduced emissions.

Mark Nemeth, project manager for BC Ferries, stands next to the bull wheels that pull Baynes Sound Connector along its center cable.

In normal operations, the engines each run 16 hours per day and switch from one to another on a staggered schedule of three or four days. This is done in such a way that there will be a 1,000-hour difference when the first engine reaches the 5,000-hour major service interval. At that point, a service vehicle will drive onto the ferry at night and, before the morning schedule, swap the engine for a new one. The engine that is removed can have the heads replaced and other services performed in time to be swapped for the second engine when it reaches its major maintenance interval.

The generators are mounted on their own separate skids. They can be uncoupled from the engines, unplugged from the system and swapped out overnight if required. Nemeth said the boat has been designed with a KIS (keep it simple) approach. The ferry’s structural design was provided by E.Y.E. Marine Consultants of Dartmouth, Nova Scotia. Seattle’s Elliott Bay Design Group completed the ferry’s general arrangements, while KPFF Consulting Engineers of Seattle provided overall engineering oversight for the marine infrastructure of the terminals and the vessel.

The two engines are in separate engine rooms arranged fore and aft in the main deckhouse. They even have separate fuel tanks in keeping with the KIS principle. Above them is a fire suppression room. All areas of the boat are fitted with water-mist fire suppression except the fire suppression room, which has separate bottles for nitrogen smothering.

The hydraulic drives and brake are located behind a bulkhead.

A smaller cabin area above the main deckhouse includes a crew head, office and coffee room, as well as a storage area. Above that is the control station, not called a wheelhouse for obvious reasons though it does resemble such. The most significant control is a lever that is in neutral position when straight up — moving it either way will propel the ferry in that direction. No navigation as we think of it is required, so the “lead operator” is not required to hold a ticket or license. In effect, it could be said, the boat never leaves its moorings.

All four of the crew hold marine emergency duty certificates. They also are trained in the vessel’s safety provisions, including operation of an outboard-powered rigid-hull inflatable boat. Last summer there was an emergency call to rescue a 14-year-old boy who swam out too far and was in difficulty. The ferry is limited by its cables and can’t vary its course, but crewmembers were able to launch the RHIB and rescue the boy.

Collision regulations and other navigational conventions also are modified to accommodate the ferry. Bright red and green LED lights are mounted on each terminal. When the ferry is secured in the slip, the lights are green to show safe passage for other vessels that need to cross over the submerged cables. When the ferry is making a crossing, the lights turn to red and vessels are prohibited from crossing the boat’s course and the cables. Traffic in the area is mostly local and limited to pleasure boats and vessels harvesting the famous oyster beds of Baynes Sound.

Lead operator Paul Vigneau surveys his surroundings from the bridge. Navigation in the traditional sense is not required on the cable ferry, so the operator is not required to hold a ticket or license.

In early March of each year, the beaches of the sound become an important spawning ground for herring. This draws a large fleet of herring seiners and packers. Once it opens, the fishery sometimes lasts only a few hours. The skippers and crews are anxious to make their sets and are not partial to any interference. No one is certain of exactly what happened this past March, but the result was some angry and accusatory radiophone exchanges. However, most agree that this was just an adjustment period and not an insurmountable conflict.

Many of British Columbia’s ferry routes face winter shutdowns for weather. More often than not, this is due to the impossibility of getting the ferry into the landing without damaging the pier or the vessel and its cargo of cars. Although it only went into regular service in February, Baynes Sound Connector did encounter 54-knot southeast winds that hit the ferry broadside on its east-west route. “But they could only push the ferry three beam-lengths over from her usual course,” Nemeth said. “And then she just sucked herself back for the landing.”

The cables for the ferry are set at 44,000 pounds of tension and have built-in load cells to monitor them. The infrastructure is designed to pull 780 tons of loaded vessel through the water. Although the channel has a maximum depth of about 195 feet, most of the crossing is in the 65- to 130-foot range. As the central cable enters the ferry, a powerful spray washes mud and seaweed off it to save wear on the bull wheels.

The cables are expected to last three years. Each year the main drive cable will be rotated out to one of the guide cable positions and replaced with a new one. The original cable will then spend two years as a guide cable.

The generators on Baynes Sound Connector, like the engines and hydraulic drives, are mounted on separate skids so they can be replaced overnight by shore crews.

While the cable rotation will be an annual task, it is the 10-year docking plan that Nemeth points to with pride. Because the ferry will need to be disengaged from its cables and towed to a shipyard, this is not something the owners want to do annually.

“All operational machinery is 7 feet above the sea surface and on the main deck,” Nemeth said. “The hull is a complete void. We don’t go down there except for an annual inspection. The seawater intake is a straight pipe with an exterior screen. It can be flushed from above or the screen cleaned by a diver. All other through-hulls are above water. Sewage is held in tanks and pumped off to a truck at night.”

For bottom paint, Vancouver Shipyards used International’s Intersleek 1100, which is designed to provide non-toxic fouling control for slow-moving vessels. Most slime that builds up during overnight moorings is cleaned during the day’s travel. As required, the hull can be cleaned at night. “We use an outfit called All-Sea Diving who bring a cube van on board and then employ a hydraulic brush that doesn’t damage the paint,” Nemeth said.

For some, the question remains: Is Baynes Sound Connector a boat or a barge? For the crowds of summer tourists and year-round commuters, their crossings by cable ferry have, after six months in service, become routine. And that is what matters.

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