‘There was no transition at all, no sense of approaching danger. It was as if I had suddenly gone blind and deaf’

The hippo who tried to kill me wasn't a stranger – he and I had met before a number of times. I was 27 and owned a business taking clients down the Zambezi river near Victoria Falls. I'd been working this stretch of river for years, and the grouchy old two-ton bull had carried out the occasional half-hearted attack. I'd learned to avoid him. Hippos are territorial and I knew where he was most likely to be at any given time.

That day I'd taken clients out with three apprentice guides – Mike, Ben and Evans – all in kayaks. We were near the end of the tour, the light was softening and we were taking in the tranquillity. The solid whack I felt behind me took me by surprise.

I turned just in time to see Evans, who had been flung out of his boat, flying through the air. His boat, with his two clients still in it, had been lifted half out of the water on the back of the huge bull hippo.

There was a cluster of rocks nearby and I yelled at the nearest apprentice to guide everyone there, to safety. Then I turned my boat and paddled furiously towards Evans.

I reached over to grab his outstretched hand but as our fingers were about to touch, I was engulfed in darkness. There was no transition at all, no sense of approaching danger. It was as if I had suddenly gone blind and deaf.

I was aware that my legs were surrounded by water, but my top half was almost dry. I seemed to be trapped in something slimy. There was a terrible, sulphurous smell, like rotten eggs, and a tremendous pressure against my chest. My arms were trapped but I managed to free one hand and felt around – my palm passed through the wiry bristles of the hippo's snout. It was only then that I realised I was underwater, trapped up to my waist in his mouth.

I wriggled as hard as I could, and in the few seconds for which he opened his jaws, I managed to escape. I swam towards Evans, but the hippo struck again, dragging me back under the surface. I'd never heard of a hippo attacking repeatedly like this, but he clearly wanted me dead.

Hippos' mouths have huge tusks, slicing incisors and a bunch of smaller chewing teeth. It felt as if the bull was making full use of the whole lot as he mauled me – a doctor later counted almost 40 puncture wounds and bite marks on my body. The bull simply went berserk, throwing me into the air and catching me again, shaking me like a dog with a doll.

Then down we went again, right to the bottom, and everything went still. I remember looking up through 10 feet of water at the green and yellow light playing on the surface, and wondering which of us could hold his breath the longest. Blood rose from my body in clouds, and a sense of resignation overwhelmed me. I've no idea how long we stayed under – time passes very slowly when you're in a hippo's mouth.

The hippo lurched suddenly for the surface, spitting me out as it rose. Mike was still waiting for me in his kayak and managed to paddle me to safety. I was a mess. My left arm was crushed to a pulp, blood poured from the wounds in my chest and when he examined my back, Mike discovered a wound so savage that my lung was visible.

Luckily, he knew first aid and was able to seal the wounds in my chest with the wrapper from a tray of snacks, which almost certainly stopped my lungs from collapsing and saved my life.

By chance, a medical team was nearby, on an emergency drill, and with their help I stayed alive long enough to reach a hospital with a surgeon. He warned me he would probably have to take off both my arms and the bottom of my injured leg. In the end, I lost only my left arm – they managed to patch up the rest.

Evans' body was found down river two days later. Attempts were made to find and kill the rogue hippo, but he seemed to have gone into hiding. I'm convinced, though, that I met him one more time. Two years later I led an expedition down the Zambezi and as we drifted past the stretch where the attack had taken place, a huge hippo lurched out of the water next to my canoe. I screamed so loudly that those with me said they'd never heard anything like it. He dived back under and was never seen again. I'd bet my life savings it was the same hippo, determined to have the final word.

• As told to Chris Broughton

Do you have an experience to share? Email experience@theguardian.com