The anchor chains descending into the depths wake us as we're mooring in the Almirantazgo Sound - a fjord that slices into the interior of Tierra del Fuego, almost severing the Darwin Mountains from the rest of the landmass.
After breakfast we're summoned to the top deck, all clad in the prerequisite wind and waterproof garb along with boots and luminous orange lifejackets.
We are the only Kiwis: there's a lone Aussie and a young Irishman who skippers barges on French canals for a living, a party of noisy Brazilians and a large tour group of Americans who receive extra educational lectures to the rest of us.
The cruise manager introduces each nationality, but there's silence when she announces there are two Russians aboard. No one acknowledges that they are Russian and everyone looks bemused - not least the two men from Belarus who don't realise they have been mistakenly identified as their-less-than beloved oppressors
I also discover, as I board the black rubber Zodiac, that I am sitting beside two Frenchmen. I remark to the one beside me that it is quite amusing to be in a Zodiac with a Frenchman.
He looks at me blankly, while across the other side, my husband is willing me to desist.
But the Frenchman is asking me to explain. Which I do, a little hesitantly, given we are now at sea in lumpy waves... it would only take a nudge and I'd be left bobbing, an Antipodean plaything for the colony of elephant seals that we are rapidly approaching.
"The Rainbow Warrior?" I proffer, watching my husband now rolling his eyes at me.
"Aaaghh. I see," my French man replies.
Adding "But it is ok, I promise I am not a French spy..."
Attention is diverted from this international incident by a dust up between two of the female elephant seals who have reared up on the beach and are thwacking each other in the chest. The rest of the colony ignores the interruption to their morning snooze, lying like vast grey lumpy sausages among the rocks.
When we disembark from the Zodiacs our guide Mathias points out a lone female cavorting in the waves beside us - cavorting being a relative term for an animal that weights about 900kg.
She is doing slow barrel rolls in the shallows, occasional swivelling her head to keep us in view but clearly not concerned by our presence. After all, she has a sizeable weight advantage, even before the impact of twice-daily four-course meals begins to tell on all of us.
Beyond the sea elephant we can see the Marinelli Glacier cascading down the mountains towards the sound.
We leave the beach to explore the Magellanic forest, which looks strangely familiar, consisting as it does of a Chilean species of southern beech, a relative of our South Island beeches.
There's even pale green plumes of lichen wafting from the branches. The ground underfoot is oozing moisture and interlaced with rivulets of water, some stained the ale colour of many South Island forest streams.
But there are some subtle differences too: there are banks of berry-clad shrubs - purple and red, all edible and - in the case of calafate - used in jams, ice creams and juices.
Mathias stops near a pond, across which has been constructed a network of tree trunks and branches - evidence, he explains, of a 19th century introduction that sounds all too familiar to us Kiwis.
Someone had the bright idea to introduce beavers here to establish a fur trade. Unfortunately there were no natural predators in Patagonia, unlike in the beavers' native North American territory, so the original few 25 pairs multiplied to a current population of 50,000.
In the process they have despoiled hundreds of hectares of pristine wilderness by killing trees and flooding the landscape with their dams.
Later in the afternoon, after Via Australis begins making its way out of the sound en route to the Beagle Channel, we stop again to visit the Tucker Islets.
The skies have clouded over and rain starts to fall as our Zodiac, with what is now known as the crew of "Non-American English speakers" sets forth.
The Belarusians don't seem to have got the memo about appropriate clothing as one is in dress shoes and corduroys and the other in jeans and a light windbreaker; presumably years of Eastern European winters have inured them to the cold.
Cliffs about 10 metres high form the edge of one side of the islet we are circumnavigating and are home to pairs of nesting imperial and rock cormorant who live happily side by side.
They repel any invaders, not by aerial attacks, but by flinging guano (excrement left by cliff-dwelling animals and birds). Apparently the rich deposits of guano that spill over each nest site are also a slippery deterrent to predators; the smell would certainly keep away most humans.
On the scrubby slopes above the cliffs, bird of prey sit in dead tree branches, ever watchful for death or injury to strike the colonies.
We zip around to the far side of the islet where a small crescent of granite-pebbled beach provides landfall for Magellanic penguins.
Several dozen of them are standing there as we glide into the beach. The birds, like the elephant seals are unperturbed by our arrival, although to ensure we don't disturb them we observe them from the Zodiacs just a few metres away.
Every now and then new arrivals porpoise in through the waves, shaking the icy seas from their feathers as they right themselves and waddle up the beach.
Magellanic penguins are only found along the waters of the Magellan Straits and environs and around the Falkland (Malvinas) Islands.
Despite there being a population of several million breeding pairs, they are classified as threatened because of their vulnerability to oil spills, which kill 42,000 adults and juveniles off the coast of Argentina alone every year.
Rain is now slanting in almost horizontally and even the Belarusians look like they are starting to freeze up.
We return to the ship to warm up, with the promise of Chilean beef for dinner and an early morning anchorage beside the Pia Glacier.
Jill Worrall cruised in Patagonia with assistance from Cruceros Australis.