There is a boat on the R/V Laurence M. Gould called the Tin Can. This boat is a metal flat bottom landing craft, the same kind that are used for military beach landings (think Normandy). The Laurence M. Gould, a 76 meter ice breaker leased by the National Science Foundation for year round polar services, carries this boat and two zodiacs for small boating operations. We normally use zodiacs similar to these for boating operations out of Palmer Station.
The main differences between the Tin Can and the zodiacs are the metal construction of the Tin Can, the shape of the hull, and the strength of the engines. The zodiacs have 40 horse power engines and a v-shaped hull with inflatable pontoons. The Tin Can has two 90 horse power engines and a flat bottom which allows way more speed when you go full throttle. She gets on plane (meaning that it gets fast enough to be cruising on the top of the waves) easily and goes through the smaller chunks of ice known as “brash” much smoother than the zodiacs. However, the boat operator has to watch out for the lower parts of the motors as he goes through it. It seems to me that if you hit the right chunk of ice you could shear the engines functionality right off.
The other disadvantage of the flat bottom hull is obvious in big swell; because of the lack of shape, the hull can't cut through water and the boat ends up sliding down the wave face unless the skipper cuts it just right (we don't dive in those conditions though, so it's beside the point). For the most part though, the Tin Can is a gem in the fleet of dive boats that we have used while in Antarctica and it comes with two fantastic operators, Chance and Toby, marine technicians on the Gould.
The genius of this boat lies not only in its speed and maneuverability. The boat’s bow can lower, creating a ramp into the water. Instead of rolling over the gunnel of the zodiac, you just take a long walk off the short ramp. Make a picture in your mind of the boats in the beginning of "Saving Private Ryan". They land on the beach where the ramps drop and the troops flood the shore. That's us storming the seas off the Tin Can.
Another aspect of this boat is the ease of getting back into it. When you finish your dive there is no need to take off your weight belt or pull yourself over the gunnel of the boat. All you need to do is writhe and undulate like a pinniped (seal) up the ramp. The ramp lowers beneath the surface of the water to make this easier for us and you can haul yourself and all of your accouterments into the boat within a fifth of the time it takes to enter a zodiac. Of course we lack a lot of the padding that a seal might have to insulate them from rough surfaces, such as those on the ramp, so we have to mind our whereabouts while doing this to prevent busting a hole in our dry suits.
Our first "live-aboard" dive trip went to the Lemaire Channel, or Kodak alley as it is sometimes called. I call this dive trip a "live aboard" because we eat, work, and sleep on the Gould during these trips and the ship's crew facilitates everything we do. We had a 76 meter ice breaker as our vessel for exploratory scientific dives.
In the Lemaire the sheer rock faces within the pass are particularly mind blowing. As you drive up to the walls in the Tin Can you slowly realize the magnanimity of their height and as you look straight up a shear, black rock face with snow and ice atop it maybe 2000-3000 ft in the air. I remember driving up in the L. M. Gould, and feeling completely subordinate and unworthy of these giants. I looked over to my friend Andrew and all I could say was "Wowowoowwowowowowowowowowow". He seconded that statement silently and that's when you know a place is powerful.
But this feeling passes as you concentrate on diving, the magnitude subsides and then you hop into the seas to dive a wall of similar structure under water. The difference above and below water is in the flora and fauna, and this brings on a new sense of awe. The abundance of seaweeds and sponges that decorate the surface of the rock faces under water are like a million brightly colored taffies within topiaries of algae that sway in the current. Currents can give algal blades a more animated presence than the fauna in these locations. Community-wise the Lemaire sites varied in some ways from the areas we normally dive, mostly in the depth stratification of the invertebrates and algae, as well as the habitats of some of the fauna.
It is safe to say that the Tin Can and Gould have expanded our diving opportunities and ability to study different communities. On our second trip we went to the Joubin Islands, closer to Palmer Station yet beyond the two mile radius for using Zodiac boats from station. On these dives, because we were so far away from glaciers and were diving alongside rocky islands, we had the best visibility yet. This area was less different in comparison Palmer than was the Lemaire, but there was an abundance of certain invertebrates and algae. Beautiful! At times we had better visibility below than we did above water because of snowfall or fog.
After the diving was done for the day and we were ready to return to Palmer Station, the Tin Can was pulled back onto the Gould using a crane, and we departed for home. All this maneuvering of gear and launching of small boats off the Gould really let us see new areas and experience different diving conditions. It's hard to say whether I'll ever experience the luxury and exoticism of a "live aboard" like that again. When you dive and see what we get to see here in Antarctica - it's beautiful and incredibly interesting. But the amount of work that goes into allowing us to do this is astounding and flabbergasting – it leaves you feeling indebted to all the wonderful support folks who make it possible.