How to Ram Your Way Through an Antarctic Iceberg

Credit: From National Geographic's "Continent 7: Antarctica"

Due to white out conditions, the residents of McMurdo Station, the largest research center in Antarctica, are reliant on year-round shipments of supplies by sea. The one problem? Miles of unyielding ice extending out from shore. For this, the United States Coast Guard brings in its 16,000-horsepower, 12,000-ton icebreakers.

“Most mariners are paid to avoid hazards,” says Captain James Hamilton, Commanding Officer of the USCGC Healy, the largest and most technologically advanced icebreaker in the U.S. fleet. “We get paid to plow through them.” We spoke to Captain Hamilton, who was also followed by National Geographic for their Continent 7: Antarctica[1] series about how these incredible machines and crews accomplish their ice-breaking tactic, known as the “back and ram," depicted above.

WHAT WENT WRONG: Climate Scientist Gordon Hamilton Dies in Antarctica[2]

US Coast Guard

Ready Your Icebreaker

“The hull of heavy class icebreakers like the Polar Star is designed for breaking up to 21 feet of ice. It is made out of specialized steel and nearly two inches thick. Then it has been formed into a boat shape reminiscent of a bathtub, with somewhat of a hammer up front. Then you factor in their power, with these ships equipped with about 16,000 horsepower, with the momentum of 12,000 tons behind it. This is more like a pickup truck than a Corvette. These vessels are designed to hit things and hit them hard.”

MORE: A Mysterious Death at the South Pole[3]

Choose Your Ice

“There are a number of tools that we use to get the lay of the ocean and how the ice is sitting on top of it. The imagery equipment and radar let us know what to be prepared for before we get to Antarctica. That way once we are there in the sea itself we know where the edge of the fast ice is. That being said the best tool for any mariner is your own eyes and experience. So that is what we trust most when we are viewing the ice edge and deciding where the ‘back and ram’ will begin.”

Engage The Target

“I would say it is more art than science. You develop a feel for your ship and how it is going to react when it hits the ice. From there it is just about getting the ship in the right position before you push the throttle down to power the engines and start making your way through the brash ice, during that you are trying to climb to the ideal ramming speed, which is about six to eight knots. Eventually the ship rides up on top of the ice with all of her weight and all of her power, right before she slams down like a hammer and breaks it.“

Prepare For Impact

“There’s no other experience on Earth like it. I’d say it is like if you combined a roller coaster with an earthquake. That is where their polar-class icebreakers come in, taking 16,000 tons of ship with 60,000 horsepower and ram it into this ice around six knots, it’s a violent explosion. The ship will shake about with quite a bit of noise. That is factored in when we are considering the crew shifts; we try to give the guys plenty of down time. Since the Polar Star was commissioned in the 70s they unfortunately put the bunks at water line, so when the ice is being broken it is pretty loud and not easy to get that rest.”

Read Your Ship

“You want to be reading your ship and your surrounding throughout. I will put two crewmembers up in a station several decks above the bridge. These crewmembers are called ‘ice pilots’. One is looking far out to strategically see what the ice is doing overall. The other is tactically looking directly in front of you. They are working closely together to time the strike and seek the path of least resistance. If you can avoid the ice, that is what you want to do, but often that is not the option. For me as Captain, beyond making sure they have a good read, I’m paying close attention to the engine as well as the rudder to make sure everything is operating optimally. Because we are going to the very end of the planet, on our own, in what I would call a self-rescue situation. If you aren’t taking care of your ship, you’re putting yourself at a lot of risk.”

Rinse and Repeat

“There is no formula that will tell you how much distance you will cover in an hour, or a day. I’ve had situations where just turning a ship around has taken about two full watches, or eight hours. It all depends on what Mother Nature is giving you, then is up to you to use these incredible machines to the best advantage to accomplish your mission. Once you’ve broken that first ice you want to try and ride the momentum, ride that strike for as long as you can until you are stopped. Then it is time to do it all over again.”

Continent 7: Antarctica[4] airs Tuesdays on National Geographic Channel. 


  1. ^ Continent 7: Antarctica (
  2. ^ WHAT WENT WRONG: Climate Scientist Gordon Hamilton Dies in Antarctica (
  3. ^ MORE: A Mysterious Death at the South Pole (
  4. ^ Continent 7: Antarctica (
back to top