Sentinel Fast Response Cutter (FRC-B)
The Sentinel-class will eventually replace the Coast Guard’s venerable Island-class 110-foot patrol boat. As operational hours for the aging 110-foot patrol boat continued to diminish, there wes an urgency to get FRCs delivered to the front lines. The FRC uses a proven, in-service parent craft design based on the Damen Stan Patrol 4708. The FRC has a 20-year service life. The cutter also meet American Bureau of Shipping design, build and class standards. These cutters provide larger and more stable platforms from which to conduct operations, safer small boat launch and recovery in heavy seas via stern ramp, the ability to detect threats at longer range, remotely operated weapons to protect the crew, and the capacity to remain on station at sea for longer periods of time.
The Coast Guard selected a “parent-craft” design for the Sentinel Class patrol boat, to ensure that the operating force receives new patrol boats, capable of performing the required missions, as quickly as possible. The Coast Guard coined the term “parent craft” to describe the use of an existing ship design that has successfully performed equivalent missions. Damen is an internationally recognized ship designer with more than 30 shipyards and related companies worldwide. Four thousand Damen vessels were placed in service since the company was founded in 1929.
In accordance with 14 USC 665, the cutter, including major components of the hull or superstructure, required by the contract may not be constructed in a foreign shipyard. In order to rapidly acquire a patrol boat with the capability to meet mission requirements, the Coast Guard employed a proven strategy of requiring industry to take the design of an operational parent craft and tailor that design within defined parameters.
This modified, parent craft patrol boat acquisition strategy has been used very successfully by the Coast Guard on past ship classes. Specifically, the Coast Guard had previously contracted with Bollinger Shipyards, Inc. to deliver two patrol boat platforms: forty-nine 110 foot Island Class patrol boats (based on a Vosper Thornycroft parent craft design) and sixty-seven 87 foot Coastal Patrol Boats (based on the Damen STAN 2600 patrol boat). Both of these platforms have proven to be outstanding successes operationally. The most recent of these, the 87 foot Coastal Patrol Boat, is particularly notable because Bollinger delivered 65 patrol boats that met all performance requirements on time and under budget.
The Sentinel Class strategy was inspired by these successes. These patrol boats are based on the Damen STAN Patrol 4708, a successful, in-service design already performing Coast Guard equivalent missions for the government of South Africa. Versions of this design had been built within Damen Shipyards and by other shipyards under licensing arrangements. Like the 110 foot and 87 foot parent craft designs, the STAN Patrol 4708 design was modified to meet specific mission requirements. As with those acquisitions, the Coast Guard contracted with Bollinger to perform this work only after a full and open competition.
The Coast Guard already had an on-site Project Resident Office (PRO) at Bollinger Shipyards. Originally established to oversee the 87 foot Coastal Patrol Boat project, this PRO also housed the Sentinel Class Contracting Officer and his staff. Coast Guard Technical Authorities and Damen Shipyards Group wwre extensively involved in ensuring that detailed technical requirements are met. The Coast Guard also used Navy partnerships and the American Bureau of Shipping for thorough review of the design, building and classing of the Sentinel and to ensure best production practices are followed.
The new Sentinel-class patrol boats will patrol 95,000 nautical miles of US coastline to conduct vital port, waterways and coastal security, fishery patrols, search and rescue and national defense missions for our nation. At 154-feet long, Sentinel-class cutters have space and berthing to accommodate a 23-person mixed-gender crew, allowing the cutter to spend as many as five days underway and will spend 2,500 hours per a year at sea. These extended underway periods, longer than any previous coastal patrol boat, will enhance the Coast Guard’s ability to carry out its underway missions.
On the FRC the main diesel engines are all electronically controlled internally, so it’s much smarter, much more responsive and it handles a lot better than other cutters. This is tremendous for someone standing watch on the bridge, who have to be focused on other tasks, such as a man overboard. Watchstanders don’t have to give special care to the engines, which can work the way they are designed to.
It has a required flank speed of 28 knots and is armed with one stabilized, remotely-operated 25mm chain gun and four crew-served .50 caliber machine guns. It uses state-of-the-market command, control, communications and computer technology that are interoperable with the Coast Guard’s existing and future assets, as well as Department of Homeland Security and Department of Defense assets. FRCs continue to build on federal, state and local agency partnerships as their integrated command, control, communication, computers, intelligence, surveillance and reconnaissance (C4ISR) systems are fully capable of operating with existing Coast Guard assets along with those of the Department of Homeland Security and Department of Defense.
The Coast Guard was very selective when using a parent craft strategy and ensuring the modifications are technically mature, and in most cases, already demonstrated. The modifications had strict limits in how they could affect displacement and center of gravity, in the case of the Sentinel it was no greater than plus or minus 10 percent displacement and plus or minus 1 percent for center of gravity. A larger, already in production MTU engine was proposed -- adding the shaft horsepower for the increased speed -- after careful calculations on engine room design, hull efficiency, etc. Lastly, the shafts and propellers were actually simplified -- going to a direct drive shaft coupled with a fixed pitch propeller, which is optimized for speed. The Coast Guard Technical Authorities carefully reviewed all the modifications.
Additionally, the government required the involvement of the American Bureau of Shipping (ABS) and the original designers throughout industry preparations of proposals and modifications to the parent craft to ensure technical risk was minimized. In the case of the Bollinger/Damen selection (Damen, Netherlands, is the designer of the Sentinel), there are examples throughout the world of successful modification of their 40 meter series of patrol boats built outside the Netherlands by non-Damen shipyards.
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