Island Scout: Good design produces a tug quieter than a Mercedes

Island Scout with her 25,000-barrel barge, ITB Supplier, at the Vancouver Island terminal.

“I took sound readings in the crew area when the boat was underway and they were lower decibels than an idling Mercedes,” said marine surveyor Marc MacAllister.

The crews that operate the tug Island Scout support Marc’s claim. “When we first had the boat,” explained Capt. Steve Clark, “we kept hearing new sounds like the revolving radar heads. With other boats the engine noise masked these low-level sounds.”
Commissioned in July 2006, the 78-foot Island Scout had been fitted out at the Island Tug and Barge shoreside facility in Vancouver Harbour. Business partners, Capt. Bob Shields and Capt. Jack Davies, are president and vice president of Vancouver-based Island Tug. Both men have spent extensive time on coastal tugs and Jack Davies is an active member of the British Columbia Coast Pilots.
On an overnight voyage from Vancouver to Vancouver Island, the two men’s names came up frequently among the crew in discussions of the vessel. It was mid-December and the night was long and dark. There was some wind from the southeast in the Gulf of Georgia, so the boat was towing rather than pushing the 240-by-60-foot double-hulled oil tank barge ITB Supplier with a mix of petroleum products in its 10 tanks.

Capt. Steve Clark at the forward controls of the 78-foot tug. The boat was fitted out in Vancouver, but the hull was built in China and broght across the Pacific on a barge.

The barge was nearly loaded to its 25,000-barrel capacity and sat low and heavy in the water, drawing over 11 feet. Getting off the dock at 0140, Mate Alex Edwards paid out enough of the boat’s 1.75-inch wire to give a separation of about 100 feet between the tug and the barge. He had already checked the tidal currents at both the Second Narrows and the First Narrows that he would have to transit on his way to open waters. Both these passes can run up to 5 knots, but this night he would pass through the Second Narrows on the tail end of the ebb so it would be running at only about 1.5-knots pushing the tow along.

As the vessels crossed the central portion of Vancouver Harbour, there was the usual mix of deep-sea and tug traffic. Edwards slowed the tow to allow a tug with 6,000 tons of gravel to clear the First Narrows and then “put the hammers down” to get past a deep-sea ship ready to come off a bulk-cargo dock on his starboard side just before the Narrows. He checked with the pilot of another deep-sea that would meet him in the Narrows and with another tug that was a little way outside the Narrows. In the tight quarters, the mate had one of the vessel’s two radars on the 1.5-mile range and the other on one-half mile. Set up on the forward console, a third screen displayed the ECDIS information along with the integrated AIS data placing the other vessels on the screen.
By 0245 Island Scout and her tow were well clear of the First Narrows and the harbor traffic, so that Edwards could walk back to the aft controls and use the remote to operate the big Burrard deck winch and let out about 1,000 feet of wire. As he did so, the hum of the hydraulics reverberated up three decks to the pilothouse. “You never would have heard that on a regular boat,” he said.
By the time Clark came back on watch just before 0600, the tug and tow were only six miles off Active Pass, another piece of narrow strong tidal water.
Tankerman David Blackburn adjusting valves on the deck of the barge.
The ECDIS showed three ferries running their early morning routes through the Gulf Islands archipelago ahead. The 550-foot car ferry Spirit of British Columbia was entering Active Pass westbound. It would meet a sister ship in the middle of the pass, leaving no leeway for a tug and petroleum barge. As the tow drew up close to the entrance of Active Pass, the wind could be heard around the wheelhouse as the boat moved comfortably up and down on the towline. The tug is designed to give enough height to the wheelhouse for visibility forward when pushing a barge, but with any swell going, the shallow notch in the stern of the barge made it impractical to push. As he prepared to enter the pass, Clark shortened up the tow again to about 200 feet.
“It gives better control in the pass and keeps it from shearing in the course of any ferry that might be coming through,” Clark said.
Along with the wind and hydraulic rumble of the winch, the sound of the radar masts revolving overhead could be heard over the faint hum of the two 12-cylinder Cummins turning at 1,600 rpm three decks below. The experience was closer to that of a sailboat than to the kind of traditional tug that gives old engineers the occupational hazard of hearing loss.
Company President Bob Shields explained that this much noise reduction requires a near-obsessive design plan. “First the framing under the engine room floors must be dense with lots of mass,” he said. “Then you must harmonically decouple the engine from the boat. This requires more than soft engine mounts. All the fuel lines, shaft and exhaust have to be soft coupled as well.”

From the aft control console on Island Scout, the winch operator can get a clear view of the towing winch and the fuel barge on the towline.

When an engine is soft mounted, he continued, it can move slightly, causing fuel lines to crack and propeller shafts to lose their alignment. To avert this and further reduce noise and vibration, they installed damping couplers on the back of the engines and then a Centa-link between that and the hard-mounted gearboxes.

The exhaust is connected to the engine with a flexible metal coupling but the exhaust piping is suspended on soft-mounted resilient hangers. The weight of the mufflers and tail pipes is supported on a shelf above the engine room deckhead, and then the tailpipe is isolated from the stacks all the way up. This allows for the system to expand when hot and move freely up and down in the stacks. Rain caps are welded to the tail pipes just above the point where they exit the stacks. “Ken Hartford of Robert Allan Ltd. (naval architects) gave us a lot of direction on this,” said Shields, “We wanted the engine noise to stay in the engine room.”
As Clark shortened up the tow before entering the currents and back eddies of Active Pass, he also lowered the hydraulic tow pins. He was able to do this from the cozy wheelhouse, while he also has an unobstructed view down to the deck winch. With 20 years on tugs, he knows the misery of leaving the wheelhouse to run aft to an outside control station in the cold and wind-blown rain. He likes working a boat designed and built by towboaters.

Tankerman Blackburn in the control room of the barge.

He explained the reason for taking down the tow pins when working in tide on a short line: “The towline can jump the pins when it is short, but then they keep it from working back; or a loaded barge can shear and the pins stop the line, so that it pulls the stern out into the channel, leaving you headed for the bank.”

The bank in Active Pass is particularly uninviting with the rocky bluffs of Galiano Island forming the northern wall.
The eastbound Spirit-class ferry had met and passed her sister and was clearing the east end of the pass as Scout entered. Having talked with the dock at Hatch Point, where he would offload the barge’s cargo and finding that they didn’t want him there until 1000, Clark had slowed down and entered the pass at 0800, bucking the last of what had been a 4.5-knot ebb. The smaller ferry Queen of Nanaimo passed red-to-red. As expected, the tide still had enough power to set a rip off a point near the entrance, sending the barge off on a shear into the middle of the narrow channel, but Scout held her course. “A good heavy boat,” commented Clark as the tug and tow moved on to buck the clean flow of the dying ebb and the barge fell dutifully in place astern.

Taken when Island Scout was under construction, this photo shows the soft-mounted engine, the flexible gear coupling and the hard-mounted marine gear.

The 78-by-25-foot hull of the boat was built in China’s Jinling Shipyard and brought over to Canada’s West Coast on a barge. When the boat is out of the water, the graceful lines of the round bilge on the hull’s 13-foot molded depth and deep nozzled props affirm Clark’s “heavy boat” observation. The raised-forecastle design common to Canadian tugs gives larger crews quarters that extend back to a fidley area where the usual steel grid has been replaced with a solid deck. This area provides for wash-up and rain-gear storage, while separating the galley from the deck and engine-room door to further remove sound while helping keep deck mess out of the living areas.

With the accommodation area having the full 25-foot beam of the boat, it was possible to put the deluxe stainless steel galley to port and the mess to starboard. Stairs to the second deck lead upward in the divider wall, while a door in the forward wall separates the three crew bunkrooms and head from the galley and mess. With two doors between the bunks and the galley chatter, the crews’ sleep is not interrupted.
“Ken Hartford recommended a system for the floor that sandwiches thin sheets of steel between two layers of a special cement material with regular rubber tile over it. For the bulkhead walls and deckheads, we used Norac, and while we lost interior volume, it has been very effective in keeping down sound. It is also used on a lot of Damen-built boats. It has both noncombustible and sound-dampening elements.”
The captain and mate have separate cabins and a head on the second deck. This is isolated from the wheelhouse by an 18-inch-high space that handles the cableways for the wheelhouse electronics.
Clearing Active Pass, Clark left the tow on a short wire, as there was no swell running here. He got a call on the radio from Scholarship, an aluminum launch that takes children to school from outlying islands. In the quiet and comfortable wheelhouse, the time passed easily. Tankerman David Blackburn came onto the bridge to confer on the ETA and offload times that he estimated at eight hours.
The forward control panel has four jog sticks for the vessel’s two props in Kort nozzles. Each prop has twin rudders for improved maneuverability. The steering can be split to allow independent operation of the port and starboard sets of rudders, although the operators seldom use this feature. Two additional jog sticks are there to provide full redundancy for the steering. Throttle and clutch controls are mounted along with the bow thruster control on the central control panel and replicated on the port and starboard wing controls.
Most British Columbian tug captains prefer to dock their barges on the tow wire. Their American neighbors just south in Puget Sound are more likely to go onto the hip of the barge and work it from there. Clark chose the Canadian approach for his landing at the Hatch Point facility on Vancouver Island. A small boat held the pollution boom open for him, and he moved slowly, bow first, toward the beach, bringing the barge in behind him just off the face of the pier. Working from the aft control station, he took into account the wind and tide to deftly use the stern fenders to stop up the barge and then had the crew drop the bridles so that he could go around and nudge the barge into the dock for the lines to be put up.
On the VHF he said to the tankerman and deck hand on the barge, “Okay, I’m just going to let her work herself in.” He made the precise movement of nearly 25,000 barrels of petroleum product in a 240-by-60-foot barge look simple.
With the barge securely moored and the tankerman working with the shore crew to pump off the 10 tanks, Clark took time to explain the advantages of an ISO 9002-certified management system. Developed with the full participation of all levels of staff, it provides for a yearly audit on each of the fleet’s vessels. Procedures are established and detailed in an onboard cabinet full of manuals for regular safety drills, work orders and virtually every other aspect of working and maintaining a tug. Where angst over additional paperwork might be expected, Clark offered only enthusiastic support. “With regular safety drills we have had everyone on board do the Williamson (man overboard) maneuver when we have an empty barge. We time them to see who is fastest. I want everyone in the crew to know how. Who knows, it might be me that goes overboard.”
Regular safety drills include both tabletop procedural reviews and actual practice under headings such as “Fire and Life Boat Drill,” “Barge Fire Drill,” “Launch Workboat,” “Man Overboard,” “Confined Space Rescue,” “Main Engine Failure,” “Compass Failure” and “Master Incapacitated.”
Another aspect of the ISO program that gets regular attention onboard is the Work Order book. Work that requires shoreside attention is entered on a white page in the book with a copy carboned onto a yellow page. The white page is sent into the office. At the same time a one-line description is made in the front of the book with the date and initial of the person submitting. Only when the white sheet is returned noting work completed is the yellow sheet replaced with the white and a date added in the completed column in the front of the book. Urgent work can be flagged in red.

The attention to detail in the construction of the boat and in its operation make Island Tug a successful company and Island Scout a successful boat. “What we are really doing is looking at what it is like to work on the water. There was a time when we all worked on vessels that were not that much fun,” Bob Shields has said. “I remember going on boats with faulty radar and leaky bunks. There is no reason not to make an investment that will reduce fatigue.”

By Professional Mariner Staff