The 'top secret' stealth boats designed for Navy SEALs that are regularly spotted on the Columbia river For more than a decade there have been sightings of unusual high-speed watercraft patrolling up and down the Columbia River between Portland, Oregon and Vancouver in Canada. The vessels belong to the Navy SEALs and are part of an ongoing project called Sealion, which stands for SEAL (Sea Air Land Commandos) Insertion, Observation and Neutralization. Despite being in existence for more than a decade, the project remains shrouded in mystery, although over the years some information has been discovered. Sealion is an experiment between the US Navy's Surface Warfare Command and the Naval Special Warfare Command. Launched in 2000, the brief was to develop a high-speed, low observable/low radar signature craft that could operate in the littorals i.e. the part of sea close to shore The Navy's intention was to use the craft as a medium-range method of transporting SEALs without appearing on the enemy's radar. Sealion is operationally controlled by Naval Special Warfare Group (NSWG) 4 at Naval Amphibious Base Little Creek, Va, reports FoxtrotAlpha. A rear opening garage-like door would allow for deployment and recovery of these craft with relative ease and without compromising the boat's stealth capabilities for more than a short period of time It appears to have been a refinement of the original design and is rumored to have offered an even lower radar cross section than its predecessor, but was also big enough to carry an unspecified number of SEALs and a modular mission payload. It also required just a single crewman to operate. The state-of-the-art electronics suite included a retractable FLIR turret, communications array and radar, along with a highly automated command and control system. According to Thompson, NSWG 4 was looking at Sealion II as a potential platform for weapons systems and intelligence collection. A rear opening garage-like door would allow for deployment and recovery of these craft with relative ease and without compromising the boat's stealth capabilities for more than a short period of time.