High winds on San Francisco Bay delayed a potential final America's Cup showdown between series leaders Emirates Team New Zealand and defenders Oracle Team USA.
A seasonally strong out-flowing tide running against incoming wind created conditions that exceeded safety limits set for the delicate 72-foot catamarans and led to a postponement of Tuesday's sailing.
A proposal by Oracle to increase the wind limits for racing was rejected by New Zealand, a New Zealand spokesman said.
Oracle's performance over the weekend suggests their AC72 is faster than New Zealand's in heavy winds, some observers believe. "We requested the wind speed to be increased by 1 knot.
"We feel the extra knot would still keep the event safe for the teams, and it would help avoid postponements like today and allow racing to continue as scheduled," Oracle general manager Grant Simmer said.
New Zealand had been in a position to clinch the cup and end the regatta if it could have won both of Tuesday's scheduled races.
It will have another chance in two races scheduled for this morning (Hong Kong time), when the weather is expected to be more favourable.
Tuesday's racing was called off after the boats headed out to the race course starting area near the Golden Gate Bridge, as whitecaps underneath grew frothier.
Organisers set strict limits on wind speeds in the America's Cup after Swedish team Artemis Racing suffered a fatal training accident in May.
Wednesday's upper limit was 20.1 knots for race one.
While 20-plus knot winds are not unusual on the bay and are acceptable for pleasure cruising, they are seen as too risky for the high-performance, hard-tomanoeuvre AC72 yachts.
New Zealand dominated racing between the two teams in the first week of the America's Cup finals, but they ran into trouble over the weekend when a vastly improved Oracle won their second and third matches, interrupting the Kiwis' momentum.