Defender - class boat The Defender - class boat , also called Response Boat – Small ( RB - S ) and Response Boat – Homeland Security ( RB - HS ) , is a standard boat introduced by the United States Coast Guard in 2002 . The boats serves a variety of missions , including search and rescue , port security and law enforcement duties and replaces a variety of smaller non - standard boats . The design length of the hull is 25 feet and the boat is officially referred to as such . However , the overall length with engines mounted is approximately . Powered by twin outboard motor s , they are capable of speeds in excess of and have a range of 150 to , depending on the class . The boat requires a minimum crew of two persons , but has a carrying capacity for 10 persons . The boat is easily trailerable and can be transported by a C - 130 Hercules aircraft or truck . Although similar in appearance to a rigid - hulled inflatable boat , the Defender is actually an aluminum - hulled vessel , equipped with a rigid foam - filled flotation collar . The boats are built by " SAFE Boats International " ( Secure All - around Flotation Equipped ) of Port Orchard , Washington , a vendor of government and law enforcement boats . Design . The Defender class utilizes a rigid deep - V hull constructed of marine grade aluminum . While similar in appearance to the sponson of a rigid - hulled inflatable boat the Defender ' s collar is actually made from rigid polyethylene foam . The boat is powered by two outboard engines , usually Honda four - strokes though Mercury and Johnson engines have also been used . Tow bitts are fitted forward and aft which also serve as mounting points for M240B or M60 machine guns . Variants . A class . The Defender A class or Response Boat - Homeland Security ( RB - HS ) was the first version of the Defender class and entered service in 2002 . Some A - class boats in service with the Maritime Security Response Team ( MSRT ) have gray collars instead of the more common orange . B class . The Defender B - class , also known as the Response Boat - Small ( RB - S ) is a further development of the A class . First entering service in 2003 it has a slightly longer cabin , additional spotter windows aft , shock mitigating cabin seats , a smaller 105 gallon fuel tank , and various other minor changes . It is the most common of the three classes . C class . The Defender C class , sometimes known as the Response Boat Small - Charlie , is a modification of the B class and was designed as a replacement for the aging Transportable Port Security Boats ( TPSB ) currently used by Port Security Unit s . The C class has a gray foam collar , a cabin climate control system , and an increased armament of one M2HB . 50 - caliber machine gun on a modified forward mount and two M240B machine guns on port and starboard mounts just aft of the cabin . The first C - class boats were delivered to Port Security Unit 305 in May 2008 for testing and entered operational service at Naval Station Guantanamo Bay , Cuba in 2009 . Service Life and Replacement . With the Defender - class boats nearing the end of the their 10 - year service life , the Coast Guard issued a request for proposal for replacement design for the Response Boat - Small . The request called for a 25 – 30 foot boat , with weapon mounts , a minimum speed of 40 knots , and a range of at least 150 nautical miles . Contracts were awarded for two boats , one from SAFE Boats International and one from Metal Shark Aluminum Boats , for testing and on September 26 , 2011 the Coast Guard awarded a contract to Metal Shark Aluminum Boats for the production of 38 Response Boats - Small .