The S2 7.3 is an American trailerable sailboat that was designed by Arthur Edmunds as a racer-cruiser and first built in 1978. The designation indicates the approximate length overall in meters.^{[1][2][3][4][5][6]}

The design was built by S2 Yachts in Holland, Michigan, United States from 1978 until 1987, with 404 boats completed, but it is now out of production.^[1][4][7]

The S2 7.3 is a recreational keelboat, built predominantly of fiberglass, with wood trim. It has a masthead sloop rig, a raked stem, a slightly reverse transom, an internally mounted spade-type rudder controlled by a tiller and a fixed fin keel or optional shoal draft keel that was designed by Graham & Schlageter. It displaces 3,250 lb (1,474 kg) and carries 1,300 lb (590 kg) of lead ballast.^[1][4][5][6]

The boat has a draft of 4.00 ft (1.22 m) with the standard keel and 2.83 ft (0.86 m) with the optional shoal draft keel.^{[1][2][4][5][6]}

The boat is normally fitted with a small 3 to 6 hp (2 to 4 kW) outboard motor for docking and maneuvering.^[4]

The design has sleeping accommodation for four people, with a double "V"-berth in the bow cabin and two straight settee berths in the main cabin. The galley is located on the port side abeam the companionway ladder and is equipped with a single sink. The head is located in the bow cabin on the port side, under the "V"-berth. Cabin headroom is 60 in (152 cm) and the fresh water tank has a capacity of 15 U.S. gallons (57 L; 12 imp gal).^[1][4]

The design has a PHRF racing average handicap of 228 and a hull speed of 5.8 kn (10.7 km/h).^[4]

In a 2010 review Steve Henkel wrote, "best features: Good space below for a 24-footer. Worst features: The old-fashioned keel design exposes so much wetted surface that we can't help but assume it slows her down in light air, compared with her comps."^[4]

• List of sailing boat types