By Peter Marsh
At the end of 2019, Brusco Tug & Barge of Longview, Washington took delivery of its eighth RApport tractor tug, Noydena, designed by Robert Allan (RAL) of Vancouver, BC, and built by Diversified Marine of Portland. On March 20, it was announced that the 82-foot overall, 6,000-hp vessel was being chartered by the Crowley Maritime’s marine service group for ship-handling service in Puget Sound after being renamed Hercules.
This design was developed from Allan’s first prototype ASD tugs for the Cates company in the 1990’s, and the RApport series was expanded to include craft from 22 to 36 meters (72 to 118 feet), featuring moderate freeboard, flush deck, and a one-man wheelhouse. More than 400 Rapport tugs have now been launched, making this the most popular design in the world, while RAL continues to develop many other tugs to suit every possible need. Brusco was one of the earliest adopters of the RApport in the USA when it ordered the plans for its first 78-footer in 1999.
All eight of Brusco’s RApports have been powered by Caterpillar 3500-series engines, which have gradually increased in rated power from 1,700 hp to 3,000 hp, with the beam of the tug also being increased from 32 feet to 40 feet to handle this huge increase in thrust. This upgrade places the new version of the design in the “ultra-wide/extreme beam” category with higher stability, especially when operating with the tow line on the beam.
In 2017-18, Diversified built two more RAL 80-foot RAmparts tugs for Harley Marine – now Centerline Logistics Corp. – that featured the first commercial installation of the Caterpillar integrated propulsion system. This represented a small revolution in the conservative world of workboat propulsion, where an owner typically chooses a different manufacturer for every component from the helm controls to the engine room and aft to the thrusters. The alternative that Caterpillar began offering consisted entirely of Cat-branded equipment, to support two Tier 3 Cat 3516’s.
Since Brusco was required to install Tier 4 engines in the new boat, that meant upgrading to the Caterpillar 3516 E with advanced SCR emission treatment. Besides this new propulsion technology, Sub-Chapter M is also requiring new alarms and safety features in the engine room.
Ensuring that all these systems from different manufacturers communicate with each other and the bridge requires meticulous planning, so Brusco decided to simplify the installation with the 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 – double the installed power of RAL’s 1990’s tugs – for a bollard pull of more than 80 tons.
The wide beam provides some extra space for a pair of 316 stainless steel urea tanks, fitted inboard of the port and starboard fuel tanks. The corrosive urea or diesel exhaust fluid (DEF) is mixed with the engine’s exhaust, causing a chemical reaction that significantly reduces NOx in the exhaust. The DEF is pumped to a dosing unit that injects precise amounts into the selective catalytic reduction (SCR) unit. This sprays the DEF into the exhaust stream where it combines chemically with the polluting gases.
Jason Spear, Caterpillar Marine 3500 product definition engineer, stated: “The advanced combustion design uses the optimum configurations and cylinder geometry, which enhances the back pressure capability, allowing the Cat Clean Emissions Module (CEM) to be the most compact and efficient SCR system on the market today, engineered from the outset for marine applications.”
The engine room layout has several other innovative features from Diversified to simplify maintenance: the main engine filters are located at floor level beside the engine in a tray to contain drips; all the bilge pump and coolant valves are 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, vice president, sales & engineering at 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 approximately 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. This adds serious firefighting capacity to the tug, and is welcomed by port and local authorities. The Hercules has a custom fendering package that 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.
Crowley’s marine services group, with US West Coast operating headquarters in Seattle, utilizes one of the most advanced fleets of ship assist and tanker escort tugs in North America. Crowley operates in some of the tightest, most environmentally sensitive waterways in the world and its West Coast ship assist and escort tugboats meet and exceed general operating standards, and are certified ISO 9001-2000 and 14001 (environmental). The Hercules will be the first RAL design to join the Crowley Northwest ship-docking and escort fleet, which currently consists of four tugs more than 100 feet long and propelled by Voith-Schneider Cycloidal drives.
“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,” said Johan Sperling, vice president for Crowley’s marine services group. “The technology on the Hercules will ensure our customers get in and out of port efficiently,” added Porter Sesnon, general manager of Crowley’s ship assist and escort services.
Diversified founder and manager Kurt Redd and his team of experienced and dedicated employees have now produced 14 RAL 80-foot ship-handing tugs in the last two decades, eight RApports plus six RAmparts. He believes the high quality of their work will continue to attract more orders coming from other established operators like Sause Brothers and Shaver Transportation.