By Peter Marsh
The Pacific Northwest has been the center for tug construction on the West Coast for at least the last 40 years, during which the azimuth stern drive (ASD) and the use of computer-aided lofting and cutting have revolutionized the way tugs are built and used. This has had the effect of allowing a typical ASD tug to become a multi-purpose craft: able to handle both ship-handling, escort and short hauling assignments with only slight additions to the deck gear.
Today, naval architects are able to take their well-tested hull shapes and modify accommodation and machinery layouts using sophisticated software to suit new demands or trends in shipping. Another virtue of design in the digital age is the ability to create virtual models in 3D for the customer to inspect before finalizing the design.
An unexpected benefit of this technology has been the ability of small boatyards to increase their efficiency and ability to incorporate design changes, which allows them to compete with larger shipyards. This has certainly been the case with Diversified Marine Inc. (DMI), located on a short length of waterfront beside I-5 on the south shore of the Columbia River in Portland, Oregon. Owner Kurt Redd opened the business in 1985 to service inland tugs and barges, and soon acquired a floating crane and a fleet of small workboats to add marine construction services.
By 1999, Redd’s company had gained a reputation for expertise in running repairs, conversions and newbuilds, and was about to enter a partnership with Brusco Tug & Barge, based 30 miles downriver in the mill town of Longview, Wash. This family-owned tug company was about to take its first step into the second generation of ASD tugs with a 78-foot x 31-foot design from Robert Allan Ltd. (RAL) of Vancouver BC (now called the RApport 2400 series) for a new contract in Port Hueneme, north of Los Angeles.
The RApport was Allan’s first series ASD design based on a prototype built for the Cates Company (now Seaspan) of North Vancouver, British Columbia. Cates was one of the first long-term clients of Robert Allan in the early 1980s. The prototype was the 73.5-foot x 28-foot Cates III fitted with twin Caterpillar 3512 engines each producing 1,175 hp turning Niigata Z-pellers.
“This was our first tractor tug with the larger radius bow, and can very rightly lay claim to being the first anywhere with a very compact, one-man wheelhouse,” Allan recalled. The dayboats have a low freeboard, flush deck and small deckhouse. Allan described them as “ideal for fast maneuvering, side-slip, and quick response in tight conditions.”
Brusco had decided that this was the best option to handle the conditions in the extremely narrow turning basin in Port Hueneme, where the first tug of the new class in the U.S., the Wynema Spirit, was assigned. It was powered by twin Detroit Diesel 1,800 hp engines and Canadian Ulstein Z-drives producing 50 tons of thrust. It was also fitted with a Markey Winch and a fire pump is capable of 1,800 gallons of water and 50 gallons of fire retardant per minute. It was joined by the Lulapin in 2005, powered by Cat 3512 1800 hp engines.
Capt. Mike Fullilove, now Brusco’s manager of operations, remembers the crew’s satisfaction with the new design. “We handle U.S. Navy ships, tankers, fruit ships, container ships, and car carriers up to 230 meters in length with very little room to spare,” he said. “They enter the port by a narrow channel and have to be turned in a 1,000-foot basin.”
This was the first of several contracts on the West Coast won by Brusco, which had Redd build the Lulapin in 2005. Since then, Brusco has expanded into a wide variety of tug and barge operations that includes ship docking in Sacramento and Stockton in the Bay Area, and Grays Harbor and Everett in Washington.
This was the start of a partnership that saw Diversified build a total of seven Rapports in 20 years, all fitted with Markey winches and powered with Cat 3512 series V-12 diesels with ratings that eventually doubled with the last 3512C rating increased to 2,375 hp at 1,600 rpm. This upgrade gave the last three boats, Bo Brusco, Sarah and Teresa, 4,750 hp turning Rolls-Royce US 205 z-drives with fixed-pitch propellers through Carbon-fiber Centa shafts. The bollard pull exceeded 60 long tons.
The Next Chapter
The next chapter in this saga began in 2018 in Canada with a major evolution in the design’s ability to accept the latest engines producing up to 3,000 hp each: the beam was increased to 40 feet, the length to 82 feet and the draft 17 feet to become the new RApport 2500 class. For U.S. customers needing to install Tier 4 SCR exhaust treatment, the extra space in the engine room is utilized to accommodate the diesel exhaust fluid tanks port and starboard.
Brusco ordered the first of this series from Diversified and took delivery of its eighth RApport tug, Noydena, at the end of 2019, specifying the latest Caterpillar Tier 4 3516 E series V-16s. Besides this new propulsion technology, the U.S. Coast Guard’s Sub-Chapter M rule also required new alarms and safety features in the engine room. Ensuring that all the engine room machinery from different manufacturers communicate with each other and the bridge requires meticulous planning, so Brusco decided to simplify the installation by specifying the fully-integrated Cat propulsion system from their local dealer, NC Power Systems in Seattle.
The complete system comprises Caterpillar helm controls and displays, twin 3516 E engines with clutches on the bell housing, with Centa carbon shafts turning Cat MTA 524 thrusters. The drives have a slip clutch function that lets the operator reduce propeller speed to as low as 35 rpm. The thruster/ASD is rotated by a pair of electric motors powered by an alternator on the main engine. The main engines are rated at 3,000 hp intermittent use at 1,800 rpm with an estimated bollard pull of more than 80 tons.
The beamier hull has a roomier galley and mess, along with laundry and a head on the main deck. Three double cabins are below deck forward for a vessel that will typically have four or fewer crew. The wheelhouse is roomier than its predecessors and is loaded with top-shelf Furuno navigation electronics. The wide beam also provides enough extra space for a pair of 316 stainless steel urea tanks. The corrosive urea or diesel exhaust fluid is pumped to a dosing unit that injects precise amounts into the selective catalytic reduction chamber, causing a chemical reaction that significantly reduces NOx in the exhaust.
“The advanced combustion design uses the optimum configurations and cylinder geometry, which enhances the back pressure capability, allowing the Cat Clean Emissions Module to be the most compact and efficient SCR system on the market today, engineered from the outset for marine applications,” stated Jason Spear, Caterpillar Marine 3500 product definition engineer.
The engine room layout has several other innovative features from Diversified for maintenance simplification, including main engine filters located at floor level beside the engine in a tray to contain drips; and bilge pump and coolant valves clustered under the ladder in a cutaway in the floor. Subchapter M now requires an enclosed fuel-fill station on the side of the house inside a spill-proof station box, with remote fuel shutdowns for fast closing of inlet valves. The gen-sets are twin Cat C7.1 129-kW units with hydraulic PTOs.
According to Scott Kreis, a sales and engineering vice president with Markey Winch in Seattle, the tug’s hawser winch has been upgraded from the 50-hp model previously fitted to the larger DEPC-52, 75-hp, single-drum electric hawser winch. This features the Markey Render/Recover automatic tension control and freewheel mode controlled from the winch station or the helm. The drum can hold 750 feet of 10-inch circumference (3.25-inch diameter) HMPE rope and is driven by a three-phase, AC 460-volt, variable frequency drive with feedback encoder. The winch has a rated performance of 30,800 lbs. at 73 feet per minute on the first layer. The air-set brake with manual over-ride can hold 678,000 pounds. Like all Markey winches, this unit incorporates anti-condensation heaters within electric motors, auto-brakes, and electrical panels. The overall weight is about 30,000 lbs.
The gen-sets also power the 150-hp electric motor that pressurizes a Carver fire pump supplying 1,000 gallons per minute to the fire monitor on the port side of the wheelhouse, adding serious firefighting capacity to the tug. The custom fendering package includes an 18-inch Shibata cylindrical fender around the bow on the upper bulwark, plus a belt of Schuyler double-loop fendering at the deck level, and covering the forward contact patch down to the waterline.
In April 2020, Brusco announced that the tug was being chartered for seven years by Crowley Maritime’s marine service group and renamed Hercules for ship-handling service at the Los Angeles and Long Beach seaports. Crowley reported that it pulled 88 tons ahead and 86 astern during trials, making it well able to handle the big tankers and containerships that visit the region’s ports.
“This high performing tug exemplifies our continued commitment to providing the best technology and performance in our fleet of tugboats on the West Coast. Our customers count on our fleet to be efficient and dependable, and Hercules adds another highly reliable asset,” Crowley Marine Services Group Vice President Johan Sperling said.
In September 2020, Brusco signed an agreement to build two more Rapport 2500s for Diversified Marine. These will be its ninth and tenth RApports from Robert Allan keeping Diversified as the top U.S. yard for production of RAL designs with a total of 16 RAL tugs including the six RAmparts delivered to Harley Marine, recently acquired by Foss Maritime. In Vancouver, RAL announced that more than 400 Rapport tugs of 72 to 118 feet have now been launched.
The performance of the first Rapport 2500 has been so successful that Allan has authorized further increases in power using the latest version of the Cat 3516E with a rating for intermittent service of 3386 bhp. The next tug will deliver 6,302 hp and the third 6,772 hp, for an anticipated bollard pull well in excess of 90 tons. Markey Machinery will again be outfitting the bow of both tugs with the same DEPC-52, 75-hp electric hawser winch.
The ASDs will again be manufactured by Berg Propulsion of Sweden. Last summer former Berg CEO Stefan Sedersten led an investment group to buy the company from Caterpillar Luxembourg, which acquired it in 2014.
“Our aim is to combine the best of two worlds, the innovative and efficient approach of the big company with the flexibility and nimbleness of the small enterprise,” Sedersten said. “I am aware Diversified Marine has been a highly valued customer to Caterpillar Propulsion and I look forward to developing the relationship between Berg Propulsion and Diversified Marine.”
Diversified Marine’s Redd said the relationship between Brusco Tug & Barge and DMI is special. “Bo Brusco is a close, close friend of mine. Over the years, we have done a lot of business together, but I have always seen him as a friend first, customer second. You don’t hear about that kind of relationship between a shipyard and operator often. Our business is built on relationships and we are thankful for the one we have with Brusco. It has allowed us to work on great, cutting edge boats and develop industry leading capabilities. We are excited to start work on the latest tug — it’s going to be a beast.”
Bo Brusco said they do not have plans finalized for where the tug will end up, and that different options will be analyzed over the course of the project. The tugs are under construction now and are expected to deliver later in 2021.