Marac was built at Ocean Racing Yachts in a Klegecell, Kevlar and S-glass layup, with hull lines that were little different to the earlier Challenge, but was slightly fuller in the bow and smoother aft, providing a hydrodynamically superior shape while also rating 0.5ft lower. Julian felt that the larger size of Marac (at 46ft) would be advantageous, compared to the minimum-rating yachts that were lining up to contest the trials, and would allow Marac to break away from the pack in the narrow confines of the Solent.
|A profile view of Challenge on which Marac was based|
|Marac being rushed along at Ocean Racing Yachts|
Another decision that was taken to optimise the design for Solent conditions was to reduce the yacht's draft. Langan described this as being mostly to do with the Solent tide; "if you're beating up against it you've got to be able to get as close inshore as possible and evey inch of draft you can save is valuable". The reduction in draft, by approximately 4 inches, also conferred a slight rating advantage. The area lost in the keel went into the rudder to maintain lateral resistance.
In the initial observation trials ahead of the New Zealand trials proper, Marac showed that she could get to the finish line first against a fleet comprised of Swuzzlebubble III, Spritzer, Feltex Roperunner and Epiglass New Zealand, but needed to put roughly 3 minutes per hour on the smaller boats to hold her place on corrected time. She was joined by Ngaruru from Wellington for the trials, a sistership to Challenge but which proved to not be competitive in the 1981 fleet.
|A bigger rudder did not always mean it ws plain sailing for Marac in the New Zealand trials series, seen here battling to stay on track on a tight spinnaker reach|
|Marac sails down past the Auckland waterfront ahead of the bunch of smaller boats|
|Marac powers upwind into the Motuihe Channel during the 1981 New Zealand Admiral's Cup trials|
|Inca working up prior to the 1981 Admiral's Cup|
|Inca (left) drifts to the finish in the first race of the 1981 Admiral's Cup trials, just ahead of the smaller Stars & Stripes (US) and Red Rock III (Belgium)|
|Inca sets off on the first downwind leg of the second race of the 1981 Admiral's Cup, just ahead of Holland's Caiman|
|Inca sailing in 1982|