Island Sky

Oct 26, 2009 12:00 AM
 
The ferry Island Sky runs just 10 miles across the mouth of British Columbia's Jervis Inlet, 65 miles northwest of Vancouver. But by agreement between Lloyds and Transport Canada, the new double-ender has been built to full Safety of Life at Sea (SOLAS) certification under International Maritime Organization (IMO) rules. The result is a beautifully functional and safe vessel built to the highest standards. As one of the crew said about the quality of the detail work, "Just look at that stainless steel piping, it is a work of art."
Island Sky's four Niigata 6L25-HX diesels, rated at 1,512 hp, give it a top speed close to 17 knots, eliminating the schedule problems that plagued the vessel's predecessor.
The boat is also fast enough to stay on schedule. Its contracted speed was 14.5 knots at 85 percent power, but Island Sky achieved 16 knots at 85 percent power on sea trials.

The route, which includes seven course changes, takes the ferry into Jervis Inlet for a few miles and rounds the top of Nelson Island before coming back to the southern landing at Earls Cove. On the ebb tide the combined drainage of Sechelt and Jervis inlets exceeds a knot of current that the ferry will buck for part of the trip. This was enough to put the vessel's 48-year-old predecessor, Queen of Tsawwassen, a few minutes behind schedule per trip, which could add up over the course of a day and cause unhappy riders to miss their next ferry connection. Now with the ferry capable of speeds approaching 17 knots there is enough flexibility to avoid that.

Island Sky's senior captain, Wayne Maxted, is particularly happy that this boat can maintain its schedule. "We are the ship in the middle," he said, referring to two other BC Ferries routes that riders on this coast are often rushing to catch. "This boat is quick."
One of the two matching control consoles aboard the double-ender, which has a Saab R4 nav system.
The hull of the 336-foot by 86.76-foot vessel, designed by Robert Armour's Polar Design and built by Vancouver Shipyards, contains seven watertight compartments. The central space includes the engine control room and a huge, well-equipped workshop and parts storage.

A watertight door at one end opens into a space with two 30-ton stainless-steel water tanks. The potable water tank is divided in two and fitted with a Hallett ultraviolet water purification system. The nonpotable tank is designed so that general use will draw down only from the top two-thirds. The intake for the ship's fire suppression system draws from the bottom of the tank so that a minimum of 10 tons of water and usually considerably more is always available for emergency use.

Beyond the next hydraulically operated watertight door, a space opens on one of the ship's two nearly identical engine rooms. On either side of the centerline is a Cat 3406-powered 280-kW genset. Outboard of these are two of the vessel's four 1,530-hp Niigata 6L25-HX main engines.

These engines turn up to only 750 rpm and deliver their power via Cardan shafts through the next watertight bulkhead to the propulsion compartment. Island Sky's propulsion is provided by four Niigata AP 21-CL Z-Pellers, one in each corner of the vessel. Power enters through a slipping clutch in the head of the z-drive that allows for slower turns at lower rpm.

From the central control and workshop compartment three similar watertight spaces extend out to the vessel's other end. The first contains the ship's Hamworthy sewage treatment plant on one side. An aeration tank moves material to a process that separates solids from liquids; the liquids are then forced through a membrane that sends them overboard in a near-pure state. The solids can be taken out by truck as required.

On the other side of this space are the components of the Hi-Fog fire protection system. With individual valves for the various passenger and crew spaces, the controller is flanked by ranks of grey and red metal bottles. Third Engineer Dana Larson, who is familiar with this system from his years on cruise ships, explained that the grey bottles contain inert gas to act as a propellant for the water in the red bottles. In the event of a fire, the fog is discharged rapidly at very high pressure. There is no danger of suffocation in contained spaces, nor is there any pollution from the inert gas.
Loading cars at the ferry's southern terminus, 75 miles northwest of Vancouver.
The engine room beyond this space is nearly the same as the other engine room but contains only one 280-kW genset. An emergency genset, identical to the three main sets, is located on an upper deck. This gives remarkable redundancy, as the whole ship's electrical systems can be operated on a single generator. In addition, battery backup would allow all of the navigation, engine control and steering systems on the bridge to continue operating with more than enough time to get to the nearest terminal in the unlikely event of a total electrical failure. Larson also pointed out that the ship's heat recovery system takes waste heat from the engines and uses it to heat the passenger areas.

Better vehicle ramps
An emergency damage control room on the main car deck level permits the operation of all engine room and firefighting systems if the engine room is evacuated. The deck's central section can accommodate semis and other high loads and allows for 125 automobile equivalent units. Galleries on both sides can take an extra 26 cars that drive up fixed ramps; loading and offloading on previous ferries was slowed by more cumbersome hydraulically operated ramps.

Two levels of accommodation provide seating for 600 passengers as well as a gift shop and snack bar. Above that, deck five is a crew deck. Deck six is a service space with electrical equipment as well as HVAC. A bridge deck above that contains two equal consoles to allow for double-ended operation.

From the operator's perspective, the MechTronics controls are the central feature. Typical azimuthing drive controls, they differ in that the left-hand control moves the two forward z-drives together while the right-hand unit controls the two stern drives. With the new ferry in operation for only a few weeks, Capt. Maxted, Chief Mate Terry Scott and Second Mate Ron Copp were still checking options to find the sweet spot for landing in varying tidal conditions. "Turning the forward drives outboard sets the side of the two forward nozzles against the water flow so it's like setting up a barn door for braking the forward movement," explained Maxted. He said his vessel was still working out the most effective balance of fore-and-aft nozzles for landings. The slipping clutch, which comes into effect under 400 rpm, is an important contributor to precise maneuvering.

The twin control centers are extremely well fitted out to meet SOLAS standards; Maxted pointed out the wheelmark logo on a number of the instrument displays signifying they meet IMO standards (Island Sky was built to Lloyds classification +100 A1 passenger and vehicle ferry). Each console has a pair of large Sperry Marine BridgeMaster radar displays and a prominently displayed Transas electronic chart system showing vessel position and heading. The z-drive control levers were supplied by B.C.-based MechTronics Technology, whose subsidiary, Impeg, supplied the Niigata engines and Z-Pellers.
Third Engineer Dana Larson with one of the Niigata main engines. Propulsion comes from four Niigata AP 21-CL Z-Pellers, one in each corner of the vessel. A slipping clutch in the head of the z-drives allows for slower turns at lower rpm.
Other devices mounted on a console between the two command stations include a Saab R4 navigation system for AIS, a SeaTechnik draft indicator, Rutter voyage data recorder, a Skipper echo sounder, Sea Marine navigation lights control panel and a control panel and indicator for the IMS watertight door system. The dazzling array of equipment will serve the ferry well when harsh winter outflow winds whistle down Jervis Inlet. But the bridge deck also boasts many decades of knowledge gleaned from time on vessels from coastal fishing boats to oceangoing ships, and it's this knowledge, accumulated by the officers who operate the equipment, that will make this a safe ship.

On a purse-strings note, B.C. taxpayers, who are often upset with cost overruns on British Columbia-built ferries, should be pleased to hear that Island Sky was built on a fixed-cost contract to oblige the private sector to be efficient. Word on the B.C. waterfront is that the ship's replacement cost could be as much as twice the C$45.5 million contracted price. It is hard to beat a fine vessel at a better-than-market price. •

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