Table 3-1 gives the average, earliest and latest dates of ice breakup and freezup. TABLE 3-1.-DATES OF ICE BREAKUP AND FREEZEUP Breakup.. Location VESSEL-TERMINAL CHARACTERISTICS, VESSEL ECONOMICS, AND TUGBOAT WITH A TOWED BARGE Port Site: Kuskokwim Bay (Cape Newenham). Terminal: Fixed pier and trestle. Tugboat Characteristics Length: 148 feet. Breadth: 37 feet. Depth: 17 feet. Draft: 14 feet. Horsepower: 8000 SHP. Hull Type: Ice Strengthened. Barge Characteristics Displacement: 16,600 long tons. Length: 430 feet. Latest May 25. Dec. 12. Required Freight Rate (RFR) to transport one long ton of cargo from Kuskokwim Bay (Cape Newenham) through Unimak Pass and to return empty equals $1.43. Required Freight Rate (RFR) to transport one long ton of cargo 1,000 nautical miles in open water and to return empty equals $4.34. ICE STRENGTHENED OIL TANKER Location Port Site: Kuskokwim Bay (Cape Newenham). Tanker Characteristics Deadweight: 140,000 long tons. Length: 944 feet. Breadth: 142 feet. Depth: 82 feet. Draft: 60 feet. Horsepower: 70,000 SHP. Hull Type: Ice Strengthened. Required Freight Rate (RFR) to transport one long ton of oil from Kuskokwim Bay (Cape Newenham) through Unimak Pass and to return in ballast equals $0.85. Required Freight Rate (RFR) to transport one long ton of oil 1,000 nautical miles in open water and to return in ballast equals $2.70. Required Freight Rate (RFR) to transport one long ton of cargo from Kuskowim Bay (Cape Newenham) through Unimak Pass and to return in ballast equals $0.90. Required Freight Rate (RFR) to transport one long ton of cargo 1,000 nautical miles in open water and to return in ballast equals $2.80. EXPOSED LOCATION SINGLE POINT MOORING (ELSPM) AS DESIGNED FOR ICE Average cost to deliver one long ton of oil from Kuskokwim Bay (Cape Newenham) to a tanker moored at the subject ELSPM equals $0.99. Location ICE STRENGTHENED OIL TANKER (OFFSHORE SCENARIO) Port Site: Kuskokwim Bay (Cape Newenham). Terminal: Exposed Location Single Point Mooring (ELSPM), as designed for ice operations. Required Freight Rate (RFR) to transport one long ton of oil from Kuskokwim Bay through Unimak Pass and to return in ballast equals $0.75. Required Freight Rate (RFR) to transport one long ton of oil 1,000 nautical miles in open water and to return in ballast equals $2.35. Cold Bay is a large deep water bay, indenting the Alaska Peninsula north of Deer Island. (See Figure 4-1.) A ten fathom natural channel passes from the sea to the Bay. This channel is very narrow, and is subject to a current velocity of up to four knots under certain tidal conditions. The Bay itself has general dimensions of five miles by ten miles. Good anchorage is available throughout the Bay with mud bottom and good holding power, but anchorages are subject to weather conditions, especially gales. Outside the entrance to Cold Bay there is considerable good deep water. However, as shown on Figure 4-2, the approach and passage to the Gulf of Alaska is dotted with small islands and shoal areas. The western shore of Cold Bay consists of low bluffs and sand beaches strewn with boulders backed by rolling tundra. The northern shore has many boulders. Lenard Harbor, on the east, is very steep on either side, offering good anchorage, but subject to significant wind force in southeasterly winds. Cold Bay forms a natural draw through which strong breezes sweep in and out. Often when there is little wind elsewhere a strong wind blows out of the Bay. A pier with an 850 foot face and depths alongside of 30 to 33 feet presently exists two miles northwest of Delta Point on the western side of the Bay. Anchorage with good holding ground can be found throughout the Bay with depths of 16 to 22 fathoms. These anchorages, however, are subject to the extreme weather conditions and no anchorage is protected from all weather conditions. Fig. 4-2 (from C & GS 8859) |