Submersible adventure


The abyss swallowed us up. The sun’s rays punched into the vastness of space clinging to us, but were unable to hold us as we were ever so slowly drawn down into the sea’s caress. The escaping air thundered towards the surface. It was the only sound until the whirl of the thruster motors kicked in. Then came the voice of our pilot, Tym Catterson. ‘Surface, we are approaching the bottom at 122 metres.’ 122 metres! 400 feet! Wow, this was the deepest I’ve ever dived. But this was no ordinary dive. I was cozy, warm and dry. There was no need to worry about decompression. I could even communicate with my fellow divers without using sign language. As far as my body was concerned, we were still on the surface. We were more than divers – we were submariners on an expedition of discovery aboard the world’s deepest classified (2001 reg) tourist submersible, in New Zealand’s natural masterpiece of world heritage status, Milford Sound.

You see the pictures on TV, you marvel at the technology, you dream the impossible dream: to experience a deep dive in a submersible. It’s not an impossible dream anymore, thanks to marine biologist Phil Mladenov. Involved with various diving studies in Doubtful and Milford Sounds with the Marine Science programme at the University of Dunedin, Phil had the idea in 1998 of a submersible in which the public could experience the diverse marine ecology of the Sounds. The submersible would also be available for scientific research.


It’s one thing to have an idea and another thing to make it a reality. So the long journey began for Phil, to find a suitable submersible. It would need to be certified to meet the stringent requirements of the American Bureau of Shipping (ABS). In a nutshell, this meant designing and building all the necessary peripherals around the main chamber structure. There was also the process of obtaining the necessary consents to run a tourism venture in Harrison Cove, in the Piopiotahi Marine Reserve, and raising the capital to make it all happen. As we go to print, the final approvals are coming through and opening day is finally in sight.

The lights of the submersible Antipodes split the darkness. The muddy surface at the base of the vertical cliff face seemed to be within arm’s reach. You lean forward into the acrylic viewing port to inspect a three-legged starfish (Allostichaster insignis); Phil, sitting beside me, says that this animal breaks in half and reproduces itself again and again. A couple of very rare opal fish (Hemerocoetes sp) rest lazily on the bottom near a couple of circular saw shells (Astraea heliotropium), a first for me. My fingers twitch as I recognize a scallop lying beside a single cup coral (Monomyces flabellum). Not to be upstaged, a rare wavyline perch (Lepidoperca tasmanica) decides to swim by and increase my never-before-seen fish list. You soon realize that this seemingly lifeless muddy bottom at 122 metres is full of life which a scuba diver never sees.


Inside the submersible, your movements have no effect on its stability. The control the pilot has is amazing. Because the Sound has virtually no currents, the submersible sits absolutely still, suspended within touching distance of the wall. The pilot can manoeuvre in fractions of a metre, up, down, fore and aft, port and starboard at the flick of a switch or the opening of a valve.

You are virtually in a fishbowl. But you are the one on the inside: the fish are outside looking at you! Just as you can walk away from a fishbowl, these inquisitive fish can be entertained by you or simply swim away. Imagine being an alien with a space window that allowed you to watch the activities of Earthlings without them noticing you. That is how it felt as we hung motionless, silently observing a marine society that did not seem at all disturbed by this huge shining bubble floating in their backyards. Numerous fish swim into our view: tarakihi, trumpeter, butterfly perch, scarlet wrasse, marblefish and Jock Stewarts. A dog shark pokes his nose in and cruises off into the darkness. Soon your eyes focus on the life that covers the walls, especially on the vertical and underhung ledges of the cliff, which the mud descending from the surface does not cover. Stunning red (Errinna novaezelandiae) and fragile lace-white corals (Errinna sp) cling under the overhangs, which are covered in a patchwork quilt of parchment worms’ calcium homes. A hiss of air, and we slowly rise up the cliff face. At 20 metres (80 feet) there is an impressive sight: a huge black coral tree (Antipathes fiordensis) fills the viewing port. The curve of the acrylic reduces the apparent size of what you see by about 20%; to compensate, you can look through the six flat viewing ports in the conning tower or through a special handheld lens designed to correct the illusion. This tree, over 200 years old, spreads its branches over three metres in height and width. Numerous snakestars (Astrobrachion constrictum), found only on black coral, enjoy their elevated position above the multitude of life fighting for space on the cliff face, including beautiful finger sponges (Raspailia topsenti) and wandering featherstars (Oxycomanthus plectrophorum).


Each black coral tree is either male or female, and during November and December the female starts to turn orange. Over about a week in February or March, they spawn. Amazing what you can learn while cruising around in a sub!

The temperature inside the sub is around 13°C, fine when you’re dressed for winter anyway. The water temperature outside is a chilly 10 degrees.

Sitting in your own air bubble, you find yourself completely absorbed by the marine life, and even better, you’re able to give it your full attention. You have a clear head – no narcosis in this baby! – no worries about your life support system or where you’re going; the pilot handles all that. You see things that you would most likely swim over when scuba diving. Not only do the pilots know how to fly this amazing piece of technology, they also have a strong understanding of the marine life. How I envied those with a degree in marine biology.


My fascinated concentration is broken as the pilot pushes the mike button to speak to the surface. ‘Antipodes is surfacing, we are about to approach the underwater observatory.’ What a great way to finish a dive: the people in the observatory could not believe their eyes when our submersible slowly rose out of the depths Their hands were waving and their cameras clicking, and their smiles said it all – ‘Wow, we saw a submersible today, unbelievable!’

I smiled back – ‘Wow, I dived in a submersible today!’ – a dream come true. I’ll have to give Robert Ballard a call, I’m sure he could use an experienced submariner on his next dive to the Titanic.


Antipodes facts

  • Capacity: four passengers plus pilot
  • Length: five metres Ports: Twin viewing ports, 1.4 metres diameter, and 635mm (2.5 inch)

    thick acrylic viewing ports fore and aft
  • Propulsion: six 2hp reversible thrusters
  • Life support system: for eight hour trip time plus 72 hours reserve
  • Lighting: two 500 watt and two 250 watt arcs
  • Power: two external battery pods, 120 volts at 165 amp hours, 24 volts at 130 amp hours in reserve.
  • Dive schedule: The submersible experience takes a total of two hours, with 50 minutes of dive time. Off-peak dives (8 am, 10 am, 3 pm, 5 pm): $395. Peak time dives (11 am, 2 pm): $495. See the ad opposite for booking information.
scroll to top