On 7 August 1962, the S-61N made its first flight. Otherwise identical to the S-61L, this version is optimized for overwater operations, particularly oil rig support, by retaining the SH-3's floats. Both the S-61L and S-61N were subsequently updated to Mk II standard with improvements including more powerful CT58-140 engines giving better hot and high performance, vibration damping and other refinements. Ansett-ANA, later Ansett Airlines, operated S-61N helicopters VH-BRI and VH-BRH on the Great Barrier Reef in support of the resorts in the Whitsundays, ferrying passengers from Proserpine to the resorts. Variants S-61L Non-amphibious civil transport version. It can seat up to 30 passengers[7] S-61L Mk II Improved version of the S-61L helicopter, equipped with cargo bins.[8] S-61N Amphibious civil transport version.[7] S-61N Mk II Improved version of the S-61N helicopter.[8] S-61NM An L model in an N configuration.[9] S-61T Triton S-61 modernized upgrade by Sikorsky and Carson; Upgrades include composite main rotor blades, full airframe structural refurbishment, conversion of folding rotor head to non-folding, new modular wiring harness, and Cobham glass cockpit avionics; initial models converted were S-61N.
