A video shared by April Boyes, 31, shows a group of orcas homing in on the yacht before attacking it, prompting one crew member to scream in terror.
The whales are seen surrounding the yacht off the coast of Gibraltar on Thursday before repeatedly slamming into it and damaging the hull. Ms Boyes can be heard saying: “Jesus, oh my God,” as each thud causes more damage to the boat, eventually destroying the rudder and piercing the hull.
The sailor says in the video says: “It’s like they are biting it apart.”
The attacks became more frequent as night falls and they whales cannot be seen but terrifying thuds can be heard as they continue to ram the vessel.
A frantic male crew member can be heard telling Spanish authorities: “We need assistance immediately, we are sinking, we are sinking.”
In the attack a crew member with a torch can be seen desperately trying to empty the rising water from the vessel’s engine room using a bucket. The four-member crew were eventually helped to safety by a Spanish rescue vessel and helicopter which raced towards them in the middle of the night.
Ms Boyes said of the ordeal: “What started off as a seemingly unique encounter ended with orcas breaking off our rudder from the boat, then proceeding to tear bits off the boat for an hour.
“A huge hole in the gull meant we had water ingress to other parts of the boat and the engine room and I can honestly say it was a scary experience. We are all safe, I’m feeling grateful for the coastguard.”
The crew was rescued by the coastguard and the 66ft-long vessel, which was sailing under a British flag, was towed to the port of Barbate, in the province of Cadiz, for repairs.
The incident follows at least 20 orca attacks on small vessels in the Strait of Gibraltar this month alone.
A female killer whale nicknamed White Gladis, thought to have been left traumatised by a collision with a boat, is thought to have taught other orcas to attack vessels around Gibraltar.
Scientists believe White Gladis is taking revenge on boats by coaching orcas, who have already caused two yachts to sink.
They think a “critical moment of agony” – in which White Gladis may have collided with a vessel or was caught in illegal fishing nets – led to her aggression to boats.
On May 2, around six orcas reportedly rammed the hull of a Bavaria 46 cruiser yacht on the Strait of Gibraltar.
The ambush lasted around an hour and left a Cambridge couple terrorised.
Janet Morris and Stephen Bidwell, both 58, were on the yacht when they were alerted with the cry of ‘orcas!’
Mr Bidwell told The Telegraph that it was “an experience I will never forget”.
“I kept reminding myself we had a 22-ton boat made of steel, but seeing three of them coming at once, quickly and at pace with their fins out of the water was daunting.
“A clearly larger matriarch was definitely around and was almost supervising” suggesting the whale was White Gladis.
Alfredo López Fernandez, a biologist at the University of Aveiro, Portugal, and member of the Atlantic Orca working group said the attacks are likely a result of past trauma.
He said: “That traumatised orca is the one that started this behaviour of physical contact with the boat.