Heaving seas test HMNZS Wellington

As one man on HMNZS Wellington remarked yesterday, you can hear about Southern Ocean storms, read about them and watch footage of them, but you'll never really appreciate their power until you see one for yourself.

So it proved yesterday as the offshore patrol vessel drove through the churning, frigid waters between Bluff and the Snares Islands, 12-odd hours after embarking on a two-week trip to the subantarctic.

Already delayed due to bad weather, the journey was accompanied from the start by rough seas which grew until the ship was forced to alter course, taking the waves front-on rather than from the side.

Never having travelled in this part of the world before but comfortable around the sea, I figured this was your average storm. However, the hints that this was not the case slowly trickled in.

Enthralled by the size of the waves and the ferocity of the sea which I surveyed with the officers from the Wellington's bridge, I said to a young sailor that the sea was impressive.

"Dangerous is what it is," he replied, only half kidding.

Lieutenant Commander Phil Rowe, captain of the offshore patrol vessel and a 28-year navy veteran told me it was up there with the roughest sea he had been in – comparable with an expedition in the Bay of Biscay years earlier.

Later, as the sea continued to swell and the winds blew harder and harder, going from strong gale to hurricane-strength as we entered the eye of the storm, he turned and admitted that it had suddenly become the biggest sea he had ever sailed in.

The ship crested waves and dove into troughs, sometimes catching so much water it painted the windows of the bridge, 16 metres above sea level, with foamy white water. The windscreen wipers, unable to keep up, were eventually torn off.

When the bow slammed into the surf and struggled to force its way back out, the ship would groan under the weight – a sound I'd only heard before in submarine or shipwreck movies.

This apparently showed the ship was under immense pressure, though officers reassured us it was built to withstand such activity.

The winds reached 90 knots before the wind tore off the wind gauge. The swell peaked at about 14m, coming constantly and often from odd directions, meaning you could never be sure of keeping your feet.

Sirens sounded regularly and loose items fell from floors and cupboards and onto the constantly shifting floor. The wind screamed across the ship's bow, dragging the pools of water which filled the deck after each wave back into the ocean.

In a lighter moment, dolphins joined the party, frolicking in front and behind the ship which trudged slowly southwest at about 6 knots – half its normal cruising speed.

Rowe had earlier sent the crew to bed as it was too rough to work. Many, along with a good chunk of the passengers, were overcome with sea sickness. One young seaman heaved into a bucket outside our room as the ship's doctor watched.

The bridge was constantly filled with people who were able to get out of their bunks and wanted to see for themselves what was happening.

It was a better place to be than lying in your bunk, I found.

Six of us are crammed into a small cabin in the rear of the boat. I've got the top bunk, where the ceiling is just 30 centimetres above my head and a sideboard is rolled up to stop me falling out.

There isn't a lot of room and from there, listening to the sounds, the groaning and warning sirens, feeling the ship pitch and roll, and knowing exactly what was happening, up the front was slightly more unnerving.

Fortunately, I was one of the minority who did not succumb to sea sickness and had to feed my sick cabin mates bread and butter to line their empty stomachs before turning in for the night.

It might not be everyone's cup of tea, but I'd take another crack – especially in a ship like this and with the crew like the one we were fortunate enough to have had on board.

We are returning to Stewart Island to undertake repairs and wait out this storm as another one enters the area.

We hope to continue our journey south – to the Campbell, Auckland, Antipodes and Bounty island groups.

The scientists on board, from MetService and Department of Conservation, have tasks to do, including pest eradication programmes, the formal opening of the subantarctic marine reserves and animal population counts.

They'll be hoping for smoother sailing from here.