The advice to stay several hundred metres away from a whale took on new resonance after the latest incident in South African waters. The owners of a well known Cape Town Sailing Academy were dismasted this week by a whale who apparently didn't notice the yacht and breached virtually on top of them.
Whale breaching beside the yacht, pictured just seconds before it crashed onto the yacht causing heaving damage
Palomo Werner and Ralph Mothes were sailing off the South African coast on their yacht Intrepid when a whale, estimated by onlookers to weigh about 40 tonnes, crashed across their yacht, inflicting heavy damage to both the yacht and itself, and dismasting it.
The couple will face questioning as part of an official inquiry into the incident. The inquiry will be seeking to establish whether the whale had faced any harassment before the incident.
'It really was quite incredible but very scary,' said Palomo Werner who was out sailing with her partner Ralph Mothes.
The aftermath - whale wins over sail
Later pictures appeared to show a wrecked mast and other damage left by the whale.
'There were bits of skin and blubber left behind, and the mast was wrecked. It bought down the rigging too,' said Werner.
Marine protection officials told South Africa's Independent Online that an investigation had been launched into claims that whale was being tormented by boats in the area.
Alan Boyd, manager for marine protection and endangered species at South Africa's environment department, said: 'We are aware of the statements that indicate that a person was deliberately sailing towards the whale and harassing it. It's good enough to investigate.'
Under laws aimed at protecting whales, sailors in South African waters must stay 300m away from them and move away if they approach.
Whale 1 Sailing boat 0
Witnesses claimed that an inflatable raft and a yacht had been harassing a whale before the incident.
Speaking before the announcement of the investigation, Werner said: 'We'd spotted it [the whale] about 100 metres away and thought that was the end of it. Then suddenly it was right up beside us.
'I assumed it would go underneath the boat but instead it sprang out of the sea. We were very lucky to get through it, as the sheer weight of the thing was huge. Luckily our yacht is steel.'