Washburn & Doughty Associates, Inc.

Washburn & Doughty Launches Freedom

On January 31, 2003, Washburn & Doughty Associates, Inc. of East Boothbay, Maine launched Freedom, the first in a series of two 4400 HP Z Drive (ASD) Tugs ordered by the Boston Towing & Transportation Company (BTT) of Boston, Massachusetts. Freedom’s sistership, Liberty, is scheduled to launch in the spring.

Freedom and Liberty measure 92’ x 32’ x 13’9" and have an estimated bollard pull of 110,000 lbs. ahead and 105,000 lbs. astern. The vessels were designed primarily to fulfill BTT’s contract with Tractebel LNG Shipping North America LLC. They will be used for assist work during inbound and outbound transits, ship docking and barge handling.

Freedom and Liberty are built to ABS class Maltese Cross A1, Maltese Cross AMS, with notation: Towing Service and Fire Fighting Capability. At completion they will admeasure less than 150 gross tons and be provided with a Load Line based on USA flag registry and USCG rules.

The vessels are powered by two Caterpillar 3516B electronic injection main engines rated at 2200 bhp @ 1600 rpm. The propulsion units are Rolls Royce 1650H Z Drives equipped with 86" stainless steel propellers and Kort nozzles lined with stainless steel. The Z Drives are the modular style for removal through soft patches on the main deck.

The two generators are Caterpillar 3304 units providing 99KW @ 1800 rpm, 120/208 volts, 3 phase with auto transfer. One generator will normally be on-line while the other is on standby.

Each vessel is outfitted with two 3000 gpm Alco fire monitors and Aurora model 411 centrifugal pumps driven by Caterpillar 3406TA engines rated 480 HP at 2100 RPM. The systems are designed to allow the crew to start and stop the pump engines from the pilothouse. Additionally, the tugs will feature deluge systems designed to provide water spray coverage over the entire tug.

The main engines, pump engine and Z Drives are keel cooled by Fernstrum grid coolers. The generators are keel cooled using the skeg as a cooler.

The Bow is fitted with a Markey type DEPCF-50 75 HP electric hawser winch, for 500 ft. of 9" synthetic line. The Winch features line-pulls up to 44,000 lbs., line-speeds up to 393 ft/min., and a drum brake holding capacity of 400,000 lbs. The Markey level-wind spools the line in such a way as to minimize pull-down during high-tension operations, and a line-tension display system provides the operator with an active display of line-tension while executing ship-docking or escort maneuvers. The Winch is provided with all electrical controls, including controls that allow the operator to freewheel the drum at any time, whether loaded or unloaded, and Markey's constant-tension "hands-free" render-recover system.

The Stern is fitted with a Markey type TES-32 75 HP electric towing winch, for 2100 ft. of 2" wire plus three layers flange-margin for synthetic line. The two-speed towing winch features line-pulls up to 156,000 lbs., line-speeds up to 86 ft/min., and a drum brake holding capacity of 400,000 lbs. A standard Markey towing winch level-wind spools the wire-rope smoothly and consistently. Special features of this towing winch include an integrated towing bitt for special operations that require manual line-handling and tie-off, a warping head with line-speeds to 60 ft/min., and a super-compact design as required for stern installation on z-drive tugs. The Winch is provided with all electrical controls, including controls that allow the operator to freewheel the drum at any time, whether loaded or unloaded, and Markey's constant-tension "hands-free" render-recover system.

The Markey Electrical Drive & Control System is based on two 75 HP AC Variable Frequency Drives which can be switched between either the Bow Hawser Winch, or the Stern Towing Winch, providing complete redundancy.

BTT has strict fendering requirements for its ship assist and barge handling tugs. The upper bow course is Viking 14" molded square fender. Below it is Viking 17" Enhanced Soft Loop to the deck level; Viking 12"x14" square fender at the deck line; Viking 17" Enhanced soft loop below the deck line to the waterline; and four courses of 18" Flanged Viking Fender below the waterline. Viking 12" black rubber "D" fender is fitted at the main deck from the bow fenders at the sides and around the stern. Additional courses of 8" "D" fender are strategically located at different points on the hull and tires are used to cover the forward sides. Stainless steel pins are used to fasten the D fendering.

The Siemens machinery alarm system consists of an integrated multi channel alarm system complete with sensors and local/remote alarm indicators. All components are completely modular and plug into a single dedicated backbone running fore and aft through the vessel.

Navigation and communications equipment include a Furuno GP-37 DGPS; a Robertson AP9MK3 autopilot; a Furuno SC-60 satellite compass; a Standard LH5 loud hailer; a Simrad RA53-4-24V radar with a 64 nm range; a Furuno 1953 C/NT-4’ scan radar; a Furuno RD-30 depth sounder; and two Standard Omni VHF radios.

BTT is a division of Reinauer Transportation Companies of Staten Island, New York.