The Cygnus 20 is a Canadian trailerable sailboat that was designed by George Hinterhoeller and first built in 1963.

[1][3][4][5][6][7] The centreboard boat was originally sold under the name HR 20, but after a class association was formed in 1965-66 the design was renamed the Cygnus 20.

It has a fractional sloop rig with aluminum spars, a spooned raked stem, a vertical transom, a transom-hung wooden rudder controlled by a tiller and a centreboard or fixed fin keel.

Normally an open boat, it can be fitted with a detachable cuddy cabin top and was advertised as being able to accommodate four people for overnight sleeping.

[1][3][5][6] The boat is normally fitted with a small 3.5 to 6 hp (3 to 4 kW) outboard motor for docking and manoeuvring.