USCGC BRISTOL BAY

WTGB 102/CGB 12001

The Ship

This ice breaking tug is named, fittingly, for Bristol Bay, a bay located within the state of Alaska and bordered by the Bering Sea. The Bristol Bay is known in the Coast Guard as a "One-Forty", a class of dual purpose harbor tugs that, while capable of ice breaking, can also be combined with a companion 120-foot Aid-to-Navigation (ATON) barge to form a much larger integrated ship unit. Sister ships on the Great Lakes include the Neah Bay (Cleveland, Ohio), Katami Bay (Sault Ste. Marie, Michigan), Mobile Bay (Sturgeon Bay, Wisconsin), and Biscayne Bay (St. Ignace, Michigan). Among the Great Lakes fleet, only the Bristol Bay and Mobile Bay have the companion ATON barge unit.

[Photo: Bow at notch in barge stern]
The bow of the tug approaching the notch in the barge.

Without the barge attached, the ship is 140 feet long and weighs over a million pounds. With 2,500 horsepower, it can continuously break ice almost two feet thick, especially when aided by its special air bubbling units which inject air under the ice to help dislodge it. Two-foot-thick ice, however, is not the upper limit, as the ship has often broken through ice windrows 10-12 feet tall.

When the Bristol Bay's bow settles into the vee-notch of the barge, the combined vessel becomes 245 feet in overall length. The ATON barge provides a large deck for storing and working aids to navigation, a crane to lift and lower these big bouys, vast storage below for auxillary gear like an underwater remote video camera, as well as additional crew berthing and accommodations. The barge has a powerful bow thruster which is controlled from the bridge of the tug, making the combined barge/tug vessel very manueverable.

Dimensions

BRISTOL BAY WTGB 102.... Harbor Tug, Medium (Total of 9 in service of this class)
Length Overall.......... 140 feet
Draft, Forward.......... 11 feet
Draft, Aft.............. 12 feet 7 inches
Beam.................... 37 feet 6 inches
Displacement............ 662 tons (1,324,000 lbs.)
Rudder.................. 11 x 13 feet
Propeller............... 4 blade, 8 foot diameter
Speed................... 14.7 knots, maxium
Range................... 4,000 miles
Propulsion
 Diesel-Generator....... Fairbanks Morse (2), [Photograph]
                         2-cycle; attached generators
   Cylinders............ 16 (opposing pistons) 
   Starting............. Compressed Air
   Horsepower........... 1460 HP (each)
   Max RPM.............. 820 Revolutions
   Lub. Oil Sump........ 320 Gallons (each)
 Electric............... General Electric DC Motor, Reversing, Direct Shaft Drive
   Voltage.............. 100 Volts DC
   Current.............. 1100 Amps
   Power................ 1000 KW
   Shaft Horsepower..... 2500 HP
Generators.............. Caterpiller 3306 (2) [Photograph]
   Power................ 180 KW (each)
Boilers................. Clayton (2)
   Heating capacity..... 25,000 BTU
Builder................. Tacoma Boatbuilding Company, Tacoma, Washington
Keel laid............... February 13, 1978
Launched................ July 22, 1978
Comissioned............. July 16, 1979

BARGE  CGB 12001
Length Overall.......... 120 feet
Draft................... 6 feet
Width................... 50 feet
Displacement............ 700 tons
Bow Thruster............ 275 Horsepower
Builder................. Marinette Marine Corporation, Marinette, Wisconsin
Keel laid............... November 16, 1990
Launched................ June 22, 1991
Delivered  ............. August 13, 1991

Crew Complement......... 3 Officers, 24 Crew