Washburn & Doughty, East Boothbay, Maine, is building at least two new 86'x35'x15'10", Tier 4, ASD ship assist/escort, Z-drive tugs for Moran Towing Corp., New Canaan, Conn. The contract includes options to build up to 10 new tugs. (The shipyard has built 38 tugs for Moran since September 1999.)
Jensen Maritime Consultants, Seattle, is doing the design work for the new 5,100-hp tugs. “There are two under contract,” said Jonathan Parrott, senior naval architect at Jensen Maritime, “and options for others.”
The new tug is the latest in a series of Jensen-designed 86 footers for Moran, with three of those having been built by Washburn & Doughty. Beyond that, “They really like the existing boats,” said Parrott, “so we are trying to minimize changes. [We’ve] basically taken that design and upgraded to Tier 4.”
In addition to the two firm tugs, which will be delivered in 2020, the contract provides Moran with four, two-tug options keyed to production milestones of the tugs then under construction. The additional tugs are expected to be a combination of the 86' Jensen design and Washburn & Doughty’s 82-MT bollard pull 93'x38' design, 14 of which are currently in service in the Moran fleet.
Main propulsion will come from a pair of Tier 4 Caterpillar 3512Es, each putting out 2,550-hp at 1,800 rpm, matched up with Rolls-Royce US 205P20 FP Z-drives. Parrott estimates that combination should produce a 68- to 70-ton bollard pull. The Z-drives will be steered by an Aquapilot control system, driving 2400mm fixed pitch propellers.
Moving up to Tier 4 power meant the below deck space at the transom was altered to accommodate urea tanks, and the main deck was raised 12". That was “so we could fit the scrubber units and all the extra stuff in the engine room,” Parrott said. And adding camber to the deck plating will allow it to shed water, thus avoiding pooling water that could freeze.
A Markey Machinery DEPC-48 electric hawser winch with Markey’s proprietary render/recovery controls and 50-hp variable frequency drive will be up forward. It will have a line-tension display system and, because “Moran wanted it,” a stainless steel brake drum for corrosion resistance and more efficient braking, said Scott Kreis, vice president of sales at Markey.
Back aft will be a Markey CEW-60, 15-hp two-speed electric capstan. “Moran owns more of those two machines than any other Markey customer,” said Kreis.
Two ship service generator sets, each rated at 99kW, 120/208 VAC, 3-phase and 60 Hz, and set up for parallel operation, will be provided. The generator-drive engines will be John Deere 4045AFM85s.
The main switchboard will be supplied by Power Panels Inc. and will feature full parallel with seamless transfer and split bus operation. It will be arranged for primary distribution of 208 VAC 3- phase, 60 Hz power.
Bow fendering will consist of one upper course of 18" and one lower course of 36" cylindrical fenders. The bow fendering will be completed by 16" soft loop, 11" mat style laminated rubber, and 12"x14" D-shaped fendering. 12"x14" D-shaped sheer fendering will extend aft from the middle bow fender and around the stern.
Accommodations will be provided for six crewmembers in four staterooms.
Each tug will be built and classed to fully comply with ABS standards, Maltese Cross A1, Maltese Cross AMS, Towing Vessel, Escort Vessel, and UWILD. The tugs will also be built and inspected to fully comply with all applicable USCG Subchapter M (Towing Vessel) regulations.