RNAS Portland (HMS Osprey)

Coordinates: 50°34′08″N 2°27′07″W / 50.569°N 2.452°W / 50.569; -2.452

RNAS Portland was an air station of the Royal Navy from 1917.

The site was first built in 1917 as HMS Sarepta within the confines of Portland Harbour as a seaplane base; the aircraft operating from the base's slipways. In 1919 No. 241 Squadron RAF (formed from RNAS flights operating there in 1918) was disbanded and aviation operations ceased.

In 1946, Hoverfly R-4Bs moved in, the base's playing fields were taken over as a landing ground and it became the site of the modern heliport. 815 Naval Air Squadron flew its 12 Whirlwinds in from RNAS Eglinton on 14 April 1959 and the station was formally commissioned as HMS Osprey on 24 April 1959.

The base was gradually improved over the years, with the addition of a (short) main runway and landing spots. It has been the home of the small ships' flight Wasp, Wessex and Lynx fleet and at one point, the slipway was used by hovercraft.

As the base wound down, Flag Officer Sea Training (FOST) moved to Plymouth (HMS Drake). The Royal Navy closed HMS Osprey on 31 March 1999.

When HMS Osprey closed, the RN School of Helicopter Control moved to its new premises at HMS Heron (RNAS Yeovilton) and the Fleet Target Group moved to HMS Seahawk (RNAS Culdrose) and became 792 Naval Air Squadron in Nov 2001.

Portland is also famous for having one of the shortest runways (04/22 at 229 m) in England. Although the naval establishment has closed, the heliport remains available for the HM Coastguard SAR flight.