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January 2012 www.sname.org/sname/mt the same hull location, are the same size, and have the identical orientation as the parent craft. Because of this identicality, FRC seakeeping performance is identical to that of the parent craft, especially consider- ing the FRC design results in a small change in full load displacement compared to that of the Damen Stan Patrol 4708. The FRC shaft line also remains identical to the par- ent craft angle, and the FRC bow thruster tunnel remains unchanged from that of the parent craft, replicating the inherent maneuverability of the parent craft in the FRC design. The FRC uses two high-performance, medium speed, marine propulsion diesels. ese are identical in type, arrangement, and configuration to parent craft prime movers for the ship?s main propulsion sys- tem. Both FRC and the parent craft use MTU 4000 series engines coupled to ZF marine gearboxes. The parent craft is equipped with controllable pitch propellers (CPP); however, the FRC uses xed pitch propel- lers (FPP) located as on the parent craft. FPP save installed weight and provide increased eciency at ank speed. Up-to-date classication Choosing a parent craft with up-to- date classification features is also critical to reduce the risk of transition- ing the design. In choosing a parent craft, Bollinger selected a design classed by an International Association of Classication Societies, Ltd. rule set that is highly similar to the American Bureau of Shipping (ABS) High Speed Naval Craft (HSNC) Guide and the requirements of the FRC Circular Of Requirements (COR). is reduces the coast guard?s design risk in evaluating a design that does not require extensive modica- tion to be classication compliant. The FRC is designed and built to the requirements of the ABS Guide for Building and Classing High Speed Naval Craft and is classed ABS A1, Circle E, HSC Naval Craft, AMS, ABCU, with SFA(25) notations. e FRC also meets the ABS R2 requirements for redundancy. e Damen parent craft was built to the requirements of Lloyd?s Register of Shipping, whose requirements are simi- lar to those of the ABS classication. Table 2 shows the very close classication relation- ship of the Damen parent craft design to the FRC design. The HSC Naval Craft notation allows the FRC to operate in the littoral environ- ment and mirrors the requirements of the Lloyd?s Register rule set for Patrol Mono and Special Service Craft (SSC) for ves- sels capable of operating in open ocean environments. is classication require- ment results in a structural design that suits the service requirements of the par- ent craft customer, the Marine and Coastal Management Branch, Department of Environmental Affairs and Tourism, Republic of South Africa. e parent craft was designed and classed for the littoral waters o the coast of South Africa and the harsh weather and seaway environment o the Cape of Good Hope. The AMS notation is assigned to machinery and pressure vessels con- structed and installed to ABS rules requirements, which also paral- lels the Lloyds Machinery Certificate (LMC). The Damen 4708 parent craft is the latest Damen patrol craft to carry the Unmanned Machinery Space Certificate (UMS), which parallels many of the features of the Automatic Bridge Centralized Control Unmanned ABCU notation from ABS. This enables the crew to focus on mission requirements instead of manning the machinery space. Bollinger has prior experience design- ing and constructing vessels to R2 and DPS-2 notations for vessels fitted with multiple propulsors and steering systems that require overall system redundancy. The inherent systems redundancy of the Stan Patrol 4708 parent craft enables FRC redundancy requirements to be met with minimal parent craft design modifica- tion. Similarly, many of the structural details required to meet ABS spectral fatigue analysis SFA(25) already exist in the parent craft?s structural details. Modifying and optimizing the parent craft design While the right parent craft selection is important, it is equally critical to be able to intelligently modify and optimize the par- ent craft design to meet the rigorous mission requirements and stringent design require- ments of the USCG and the navy. The hull of the parent craft is of all welded steel construction, with plating and scantlings designed in accordance with the minimum scantling requirements of the Lloyds High Speed Craft rules. e parent craft hull plating was designed in anticipa- tion of the rugged conditions expected in the Southern Ocean. The framing and grillage of the FRC remains the same as the parent craft with the only signicant changes to structure being those to support additional subdivi- sion bulkheads for damage stability, local structure to support resized equipment, or Parent Craft FRC Design Classication societyLloyd?s Register of Shipping American Bureau of Shipping Structural notation 100 A1A1Design servicePatrol Mono, Special Service Craft (SSC), G4HSC Naval Craft Machinery notationLloyds Machinery Certicate (LMC) AMSMachinery spacesUnmanned Machinery Space Certicate (UMS) ABCU Anchoring equipment Circle E Fatigue analysis SFA(25) TABLE 2. CLASSIFICATION RELATIONSHIP, PARENT CRAFT TO FRC e Parent Craft Model 26_31_FanguyFRCfeature_SNAME_Jan12_P3.indd 3012/22/11 3:37 PM