48°47′03″N 87°25′20″W / 48.78417°N 87.42222°W / 48.78417; -87.42222

Gunilda was a steel-hulled Scottish-built steam yacht in service between her construction in 1897 and her sinking in Lake Superior in 1911. Built in 1897 in Leith, Scotland by Ramage & Ferguson for J. M. or A. R. & J. M. Sladen, and became owned by F. W. Sykes in 1898; her first and second owners were all from England. In 1901, Gunilda was chartered by a member of the New York Yacht Club, sailing across the Atlantic Ocean with a complement of 25 crewmen. In 1903, she was purchased by oil baron William L. Harkness of Cleveland, Ohio, a member of the New York Yacht Club; she ended up becoming the club's flagship. Under Harkness' ownership, Gunilda visited many parts of the world, including the Caribbean, and beginning in 1910, the Great Lakes.

In the summer of 1911, Gunilda's owner, William L. Harkness, his family and friends were on an extended tour of northern Lake Superior. They were headed to Rossport, Ontario and then planned to head into Lake Nipigon to do some fishing for speckled trout. As she was about 5 miles (8.0 km) away from Rossport, Gunilda ran hard aground onto McGarvey Shoal on the north side of Copper Island. Most of the passengers were taken to Rossport. Harkness stayed behind to supervise the salvage, hiring the tug James Whalen and a barge to tow Gunilda off the shoal. On August 11, 1911, after she was pulled free, she suddenly rolled over to starboard, filled with water, and sank. Harkness and his family were picked up by James Whalen.

Her wreck was rediscovered in 1967 resting in 270 feet (82 m) of water, completely intact, with even the gilding on the hull surviving. Gunilda's wreck was the subject of multiple failed salvage attempts. In the late 1960s, Ed and Harold Flatt made multiple unsuccessful attempts to salvage her. Throughout the 1970s, Fred Broennle also made several unsuccessful attempts to raise Gunilda. In 1980, Jacques Cousteau and the Cousteau Society used the research vessel Calypso and the diving saucer SP-350 Denise to dive and film the wreck. The Cousteau Society called Gunilda the "best-preserved, most prestigious shipwreck in the world" and "the most beautiful shipwreck in the world".

Gunilda (UK official number 104928) was built in 1897 by Ramage & Ferguson in Leith, Scotland. Her hull number was 149. She was designed by Joseph Edwin Wilkins, a naval architect who worked for Cox & King of Pall Mall, London, England. She cost about $200,000 to build. Her name is a variant of Gunhild, an old Germanic feminine name meaning "war". She was launched on April 1, 1897.

Her steel hull was 195 feet (59 m) long; one source states she had a length of 177 feet (54 m), another source states she had an overall length of 177.6 feet (54.1 m) and a below waterline length of 166.5 feet (50.7 m), her beam was 24.7 feet (7.5 m) (one source states 24.58 feet (7.49 m). Several sources state she had a draft of 12 feet (3.7 m), several other sources state her draft was 14.2 feet (4.3 m), and one source states she had a draft of 14.16 feet (4.32 m). She had a gross register tonnage of 385 and a net register tonnage of 158. She had a Thames Tonnage of 492 or 499 tons.

She was equipped by a triple expansion steam engine with pistons that had bores of 15 inches (38 cm), 24 inches (61 cm), and 37 inches (94 cm) and a stroke of 27 inches (69 cm). The engine was powered by steam produced by two 160 psi turbine boilers. Gunilda was driven by a single propeller and had a top speed of 14 knots (16 mph) (some sources state 12 knots (14 mph)).

Between 1897 and 1898 Gunilda was owned by either J. M. Sladen or by A. R. and J. M. Sladen; her home port was Wivenhoe in England. Her second owner was F. W. Sykes, who owned her between 1898 and 1903, during which time her home port was Leith. Her first and second owners were from England.