The US Coast Guard is a multimission, maritime military service within the Department of Homeland Security. The Coast Guard has responsibilities that fall under two broad missions—homeland security and non–homeland security. (See table 1.) One of the Coast Guard’s strategic goals is maritime mobility, that is, to facilitate maritime commerce, eliminate interruptions and impediments to the movement of goods and people, and maximize access to and enjoyment of the water. The two non-homeland security missions through which the Coast Guard achieves this goal are aids–to-navigation (ATON) and domestic icebreaking, which is part of ice operations. Aids-to-Navigation Mission Through its ATON mission, the Coast Guard promotes safe waterways and an efficient Marine Transportation System. The Coast Guard has statutory responsibility to operate and maintain a system of maritime aids to facilitate navigation and to prevent disasters, collisions, and wrecks. To fulfill this mission, the Coast Guard operates over 53,000 aids. These aids- to-navigation are like road signs of the waterways and are placed along coasts and navigable waters as guides to mark safe water and to assist mariners in determining their position in relation to land and hidden dangers. These aids consist of both floating aids, such as buoys, and fixed aids, such as lights or signs mounted on pilings. See figure 1 for an example of a buoy and fixed aid-to-navigation. The Coast Guard uses several types of vessels to place and service its aids- to-navigation such as buoy tenders, construction tenders, and boats that make up its ATON fleet. These vessels are used to perform both periodic routine maintenance of aids and discrepancy response, when, for example, a light is extinguished or a buoy is moved from its intended location. The assets are shown in table 2. Domestic icebreaking is a key component of the Coast Guard’s ice operations mission, which facilitates the safe and efficient navigation on lakes, rivers, channels, and harbors during the winter season. The Coast Guard has statutory icebreaking responsibilities that are additionally addressed by an executive order that directs the Coast Guard to break ice in channels and harbors in order to keep them open to navigation. Like plowing snow-covered roads, the Coast Guard keeps areas of water open as much as is reasonably possible for commercial traffic in winter. It also performs icebreaking for search and rescue and prevention of flooding by ice. To conduct this mission, the Coast Guard uses assets that are specially designed with strengthened hulls. The key icebreaker types the Coast Guard uses are shown in table 3. The Coast Guard classifies its vessel assets, such as those used in the ATON and domestic icebreaking missions, as cutters (assets 65 feet long or longer with adequate accommodations for crew to live on board) or boats (assets less than 65 feet in length that usually operate near shore and on inland waterways). For purposes of this report, the three main asset groups are ATON cutters, ATON boats, and domestic icebreakers. Since 2001, the Coast Guard’s domestic icebreakers and ATON cutters have experienced significant increases in the time spent conducting missions related to homeland security. Most of this increase has come in the Ports, Waterways and Coastal Security (PWCS) mission, which involves such activities as conducting security patrols and escorting vessels. The increase was greatest for domestic icebreakers, which continue to be used more for homeland security missions than for icebreaking because of their availability during months when no icebreaking is needed. By contrast, ATON cutters and boats still spend most of their time on ATON-related activities, reflecting the year-round nature of the ATON mission. Some newer ATON cutters with greater multi-mission capabilities, however, continue to have a more diverse workload. Coast Guard officials said icebreakers and ATON vessels, while less than ideal for carrying out security missions, can perform these missions adequately. During fiscal years 2001 through 2005, the domestic icebreakers divided their time between several of the Coast Guard’s 11 missions, but PWCS activities accounted for roughly half of all resource hours during fiscal years 2002 through 2005. PWCS activities grew quickly from 15 percent of total resource hours in fiscal year 2001 to 53 percent in fiscal year 2002, and they have remained at 44 percent or more of total hours through fiscal year 2005. At the same time, icebreaking hours began at 41 percent in fiscal year 2001 and then dropped down to 13 percent in 2002, but ended at 26 percent in fiscal year 2005. The vast majority of this increase in PWCS has occurred in the New York City area with smaller increases in other East Coast ports. As figure 2 shows, the increase came about largely by adding to the total number of hours these assets were operated. The total number of resource hours for these assets grew from about 12,000 hours in fiscal year 2002 to a high of about 20,000 the following year. The increase in PWCS hours for domestic icebreakers mainly reflects their availability during those months when no icebreaking needs to be done. Icebreaking needs are typically greatest from December 15 to April 15. Coast Guard officials said that because icebreakers do not have a primary summertime mission, using them to conduct PWCS missions during slack periods has not limited the Coast Guard’s ability to conduct routine icebreaking missions. Icebreaking hours, however, did see some marked shifts during this period—most notably a decrease in fiscal year 2002 followed by a substantial increase in fiscal year 2003. The decrease in 2002 appears related to two main factors: a mild winter, during which the Great Lakes region was virtually free of ice throughout December and most of January, and a change in the way the Coast Guard accounted for its use of icebreakers. The Coast Guard does not record resource hours under two mission categories simultaneously, and prior to the attacks on September 11, 2001, resource hours used to break ice while escorting a vessel with hazardous cargo would only have been recorded as ice operations. After the attacks, these same hours could be logged either as PWCS or icebreaking at the discretion of the vessel’s commanding officer. The increase in ice operations hours for fiscal year 2003 reflected an unusually severe winter in the Great Lakes. Increased workloads have placed some icebreakers above the maximum number of recommended operating hours for the assets. The maximum recommended operating level, called an “underway hours limit,” reflects maximum use established from planning documents, missions, and maintenance requirements, and historic use. In particular, the 65-foot small harbor tug fleet exceeded their underway hours limit from fiscal years 2001 to 2003 by increasingly more hours, starting with being 10 hours over the underway limit in 2001 and progressing to nearly 2,000 hours over the underway limit in 2003. In contrast, the 140-foot icebreaking tugs were operated within their underway hours limit from 2001 to 2005. Coast Guard officials said domestic icebreakers, while not their vessel of choice for maritime security missions, can perform all PWCS missions adequately except for shore side patrols. The Coast Guard’s 87-foot coastal patrol boats are the preferred assets for PWCS missions. Commissioned since 1998, these boats can travel at up to 25 knots and have a system that allows the crew to launch and recover small boats. Relative to these vessels, domestic icebreakers show both advantages and disadvantages (see table 4). Icebreakers are more capable of operating in cold weather, and their substantial size provides a significant presence on the waterways, but they are slower, less able to launch small boats, and pose increased training challenges for training crews in law enforcement. ATON assets also experienced an increase in use for homeland security missions after September 11, 2001, but to a much lesser degree than for domestic icebreakers. Overall, ATON assets were used for several of the Coast Guard’s missions during fiscal years 2001 through 2005, but ATON remained the primary mission, accounting for more than 85 percent of the fleet’s total resource hours for fiscal years 2001 to 2005. Time spent in PWCS activities increased from 4 percent of total resource hours in fiscal year 2001 to 10 percent in fiscal year 2002; since then, PWCS mission hours have steadily decreased (see fig. 3). Overall, PWCS activities accounted for 6 percent of resource hours during the period. When resource hours are analyzed more closely by type of ATON asset, there are significant differences in the amount of hours used for the PWCS mission. The increase in PWCS resource hours came primarily from cutters (vessels ranging in length from 65 to 225 feet). Overall, ATON activities account for about 79 percent of total resource hours for the cutters, compared with about 90 percent for ATON boats (vessels less 65 feet in length). ATON boats were the only vessels that did not have as much of an increase in PWCS resource hours immediately after the attacks on September 11, 2001, though their use in PWCS activities did rise in fiscal year 2003. Among the ATON cutters, the newer cutters have greater multiple mission capabilities and consequently tend to be used more often in other missions. For example, ATON cutters acquired between 1944 and 1976 performed an average of 4 of the Coast Guard’s 11 missions during fiscal years 2001 through 2005, while the 225-foot seagoing buoy tender, which the Coast Guard completed the acquisition of in 2004, was used in all 11 of the Coast Guard’s missions in fiscal years 2004 through 2005. The available evidence does not give a consistent picture of how usage trends may be affecting the condition of these assets and, ultimately, the Coast Guard’s ability to meet performance goals for icebreaking and ATON missions.