In 1984 American yachtswoman Elizabeth Meyer bought JK4 Endeavour and undertook a five year rebuild. Since the hull was too fragile to be moved and was miles away from any boatyard, Meyer had a building constructed over the boat and hired welders to restore the hull. Endeavour's missing keel and ballast were rebuilt, the steel frames and hull plating repaired and replaced where necessary, and a new rudder fabricated. The newly seaworthy hull was launched and towed to Holland where it was put on a barge and transported to the Royal Huisman Shipyard. There, the mast, boom and rigging were designed and built, the engine, generator and mechanical systems installed and the interior joinery completed. Endeavour sailed again, on June 22, 1989, for the first time in 52 years. Between 1989 and 1999 Endeavour cruised extensively and competed in numerous races, creating a wonderful spectacle In April 1999, history repeated itself when she was joined by Shamrock V and Velsheda to compete in the Antigua Classics Regatta, bringing in a new era of J Class sailing a sight not seen in over 60 years. Endeavour, Velsheda and Shamrock raced together at the J-Class Regatta for the first time in UK waters after more than 65 years. Endeavour won both regattas after close racing between the yachts.
JK4 Endeavour underwent an extensive refit again in 2010/2011. Dykstra Naval Architects were the Naval Architects responsible for the construction, sail plan and deck layout on a project that was carried out by Yachting Developments in Auckland. The refit included a new deck structure, new rig and sails, a new deck layout, an engine room upgrade and a new crew interior. Jon Barrett, who oversaw the yacht's first refit as captain at Royal Huisman in 1989 (which, incidentally, was also Gerard Dijkstra's firtst major J-Class refit) was project manager for this prestigious project that resulted in a "ready for battle" Endeavour.
Dykstra Naval Architects have gained over 30 years of J-Class experience and where responsible for the rebuilds of the J-Class yachts: JK3 Shamrock V, JK7 Velsheda, JK4 Endeavour, performance refit of J5 Ranger, the new builds JK6 Hanuman and JH2 Rainbow and J Yankee on the drawing board. To keep the J-Class fleet and races alive and to encourage new build yachts to enter the field, new JCA maximum performance rules have been developed, including allowing aluminum as building material. The new rule is a VPP (Velocity Prediction Program) based rating system which puts limits to the performance. This new rule has been developed by the Dykstra Naval Architects office and the Wolfson Unit in Southampton. The aim of the JCA, the Dykstra team and the rule is to bring fair & close racing to the fleet and to give all designs a chance of winning (on a handicap based system). Over the years the Dykstra team gained an enormous amount of hands-on information by racing on all the Dykstra J's in the current fleet.