Marine radio operator Martin Balch said Potamos’ mast broke during an annual race to Waikouaiti Bay from the head of Otago Harbour.
The race was called off because the wind exceeded allowable upper limits and the boat had to be towed back to Careys Bay because its motor had jammed.
Mr Balch said the mast had broken in a pretty unusual place, but fortunately it did not do any damage to the boat.
He said the wind was about 25 knots and probably gusting to about 35 knots.
Later in the day the tourist vessel Monarch also had to be towed to Careys Bay after its engine failed.
Monarch owner Jerad Haldan said its engine had also failed a couple of months ago and he was looking for a new one.
"Old boat engines aren’t your friends," he said.
The company’s cruises were not disrupted as its second boat, Vivian J, was able to replace the 17m-long Monarch.
