The Golfo de Penas is a long way from anywhere. It is one of the major barriers to safe navigation along the already formidable coastline of southern Chile. The Taitao Peninsula, which forms its northern coast, juts its curved finger 40 miles westward into the swells of the South Pacific, forcing the sailor to leave the relative safety of the Chilean fjords to scuttle as quickly as possible across its great embayment, exposed to the fury of the open ocean.

It forms the crux point of the month-long passage from Puerto Natales in the south to Puerto Montt in the north. Fierce currents and precipitous waves discourage any loitering along this 140-mile passage.

Loitering with (scientific) intent was what we happened to be doing late that autumn, however. Using our recently acquired yacht, Saoirse, we had embarked a team of scientific divers headed by Dr Vreni Haussermann to explore the vast underwater treasure trove of benthic life hidden below the Patagonian waters.

These voyages of discovery are always exciting; we get to find new species and witness the colourful life that teems below the surface of the fjords, but our trip with Vreni and her divers that autumn took a tragic turn.

“There’s another one over there,” Keri announced over the radio. With dusk falling quickly, a dinghy full of scuba equipment and cold, hungry divers champing to get back to the warmth of the boat and discharge their day’s discoveries into the pilothouse, it was hard to get excited about anything else. Still, I looked into the gathering dark to see another indistinct pink blob lying on the beach about a mile to the south.

A quick glance through the binoculars confirmed it. Another whale carcass, lifeless on the shore of Puerto Slight. “That makes ten just today,” she said grimly, “and add that to the four we saw last month on the geology trip. There is something very strange going on here.”

By the time we turned Saoirse’s bow south to return across the Gulf we had counted nearly 30 recent whale carcasses scattered in Puerto Slight and Bahia Hoppner alone. Over the many years we have spent sailing these southern fjords we have all seen the odd dead whale lurking in the trees, gone to take a look as long as the nauseous smell would permit, but none of us had seen anything like this. It was about to get worse though, much worse.

Evidence from the air

Sometime after we had finished our expedition and completed the long voyage back to Puerto Williams, we received some stunning news from Vreni. She had reported what we had found to Sernapesca (the Chilean Fisheries Department), but faced a wall of indifference. Acting on a hunch, she had hired an aircraft to overfly the area and bought some high-resolution satellite photos.

The views from above revealed the massive extent of the carnage; the body count came to 337 whales scattered about the beaches, and this was only the confirmed ones. Who knew how many more were outside the purview of the photo surveillance or sunk to the bottom? It would be confirmed as the biggest whale stranding event in recorded history.

“We can’t ignore this, we must do something about it. It’s very important,” Keri stressed months later, while we were gloomily working our way through the mindboggling array of permissions needed for a proposed tourist trip to Antarctica. I agreed, but what could we do?

During our trip back south the story of the whale deaths had made international news, but Chile’s scientific world was in an uproar. Incredible as it may seem, the efforts of Vreni and her colleagues to study the phenomenon had set the factionalised science community to public warfare. So many insults were being hurled back and forth about the handling of the discovery that finally the public prosecutor of Aysen placed a ban on all further studies in the region for at least two years.

This was utterly absurd; the only way to find out how and why the whales had died would mean immediately returning to the Golfo de Penas with a specially equipped and permitted scientific team, but by now we were nearly 1,000 miles away, committed to be heading in the opposite direction. It all seemed impossible.

A few days later, our Antarctic trip had been cancelled, we had found a sponsor to cover the costs of the expedition and we were again northward bound. Expedition ‘Return to the Whales’ was born.

Assembling the crew

The expedition took shape very quickly in January. At the start we really had no idea of the type and quantity of data we would have to collect for the investigation, nor who could come to help us with it. For sure it was going to be a somewhat gruesome affair at times. Also we needed to do impeccable science.

“Have you ever cut up a whale before?” Keri asked Alexandra Luiso, our vet who had come across from Ushuaia to visit and was just then grooming and deworming our dog, Pichi, at the Micalvi Yacht Club.

“No,” she said, “but I have dissected a few birds, I’ve got time off and I am a veterinarian.” She quickly agreed to volunteer for the trip.

Katie McConnell, a Californian science diver, who had assisted Vreni with many of her benthic dive study projects, chimed in with an immediate: “I’m in!” She would act as crew and science adviser. One by one, other volunteers materialised: four graduate students of oceanography, palaeontology and marine biology rounded up by Vreni and her colleague Dr Carolina Gutstein of the University of Chile, who had between them constructed the scientific programme. We would pick them all up 650nm away in Puerto Eden in two weeks.

Skip Novak goes sailing to climb mountains – in the wake of Tilman

On 14 January we tightened down the last of the bolts on the brand new hydraulic windlass that had just arrived to replace the last one, which had ground to a halt on the previous trip. Loaded with 8,000lt of fuel, formalin, alcohol, plankton nets, a chainsaw, two dinghies, three outboard engines and some suits that looked as if we were headed into an Ebola zone, we were off.