A container ship and a French-registered yacht were also directed towards the sloop's position.
Safely back on dry land, Mr Galloway, who lives at Otaki Beach, said he and his crew were tired and hungry.
"We haven't had cooked food for two days, and we didn't sleep last night of course," he said.
Freedom Hunter was en route to Opua from Fiji when the motor malfunctioned after the pump, which had been refitted in Fiji a week before sailing, failed one day into the voyage.
Mr Galloway was woken by a "funny noise at 11pm on Tuesday.
"I had a look down the hatch and saw about a metre of water in the bottom of the boat.
"We all worked like mad with electric and hand pumps," he said.
He called Maritime NZ with a Pan Pan call at 11.40pm, and upgraded that to a Mayday which was picked up by the Rescue Co-ordination Centre at 12.16am.
At that stage Freedom Hunter was 28 nautical miles off Great Exhibition Bay.
"That activated everything; first the helicopter and then the Coastguard," he added.
"The seas were crazy, the winds were crazy. It was a dark black night."
Mr Galloway, who bought Freedom Hunter in 1986, said he had "thankfully" never experienced anything like that before.
"This boat and I have been around the world and back, been to the Pacific numerous times with no worries," he said, adding that he wanted to thank Coastguard, which had done a "really tremendous job with helping us."
Freedom Hunter was met at Mill Bay by Customs, in accordance with standard practice.