She was built for Thomas Sopwith who used his aviation design expertise to ensure the yacht was the most advanced of its day with a steel hull and mast.

[4] Endeavour pioneered the Quadrilateral genoa, a twin-clewed headsail offering great sail area and consequent power.

[4] Endeavour was originally fitted with a flexible boom that allowed the foot of the mainsail to bend into an aerodynamically efficient shape.

[6] The 1930 Cup winner Enterprise had demonstrated the advantage of allowing the foot to bend this way, albeit using a completely different mechanism (the "Park Avenue" boom).

[8] Endeavour raced in the 1934 regatta season in the "Big Class" against Astra, HMY Britannia, Candida, Shamrock (ex-Shamrock V), and Velsheda.

[14] This tour led to a protest by Sopwith that Rainbow had not followed the spirit of a new rule introduced to the competition that year that yachts should be fitted out with crew accommodations.

[14] The Cup Committee responded to the protest by allowing Sopwith to strip out large parts of Endeavour's interior prior to racing.

[15] However, Rainbow won the third and fourth races due to better tactics, including a maneuver which led Sopwith to protest unsuccessfully to the Cup Committee.

The initial work was undertaken where she lay to ensure that the hull was sufficiently seaworthy to be towed to the shipyard of Royal Huisman, in Holland, who designed and installed a new rig, engine, generator and mechanical systems and fitted the interior to a very high standard.

[20] In a 2014 interview with CNN she described a "restoration urge" as being "inherent in the human nature" and said that she "immediately went 'Oh no'" when she realised the enormity of this task and that it fell to her.

[22] She needed 90 professional sailors to crew the two yachts but could not afford to pay them; despite this, the appeal and prestige of the restored J‑Class was so great that she was inundated with several hundred applications.

[23][25][26] In 2011, Endeavour completed an 18-month refit in New Zealand, during which a carbon-fibre mast and standing rigging were fitted and some changes were made to the deck layout.