The art & science of ice breaking

Cutter Healy escorts Renda

The Russian tanker Renda transits through the Bering Sea with Coast Guard Cutter Healy’s assistance Jan. 10, 2012. The Renda is carrying 1.3 million gallons of petroleum products for delivery to Nome. U.S. Coast Guard photo.

As the nation continues to track the historic journey of Coast Guard Cutter Healy and the Russian-flagged tanker Renda through approximately 300 miles of ice-covered Arctic waters towards the small Alaskan town of Nome, some may ponder the unique capabilities of an ice breaking ship.

One reader commented on a recent blog post, “The engineering of ice breakers really interests me, as well as the methods used to break ice and escort ships.”

With the ships currently about 100 miles from Nome, building winds in the forecast and increasingly thicker ice, a Coast Guard specialist discusses the art and science behind Healy’s ice breaking capabilities.

Written by Lt. Cmdr. Kristen Serumgard, Coast Guard Office of Cutter Forces.

Daring to do what other ships ardently avoid, Healy is purposely designed to run into things – specifically, ice. While moving at three knots, Healy can continuously break 4 1/2 feet of ice. When encountering thicker ice, Healy can break up to 8 feet through a process called “backing and ramming,” repeatedly striking the ice in a controlled manner to break through a ridge.

While significant engineering goes into designing an icebreaker, breaking ice is based on two simple principles: (1) a sledgehammer is better than a butter knife and (2) two objects cannot occupy the same space at the same time.

Healy’s rounded, blunted bow

This photo from a 2009 science mission illustrates Healy’s rounded, blunted bow that enables it to ride up on top of the ice to break it. U.S. Coast Guard photo by Petty Officer 3rd Class Patrick Kelley.

Simple principles

Most seagoing vessels have a pointed bow designed to “cut” through the waves. For ice breaking, this is not the most efficient design.

Healy is designed with a rounded, blunted bow that enables it to ride up on top of the ice. As the bow raises up and the stern sinks below the water, the force of buoyancy acting on the submerged portion of the stern – think of putting a basketball underwater! – creates a lever-like action bringing Healy’s 16,000 tons down onto the ice and breaking it. Depending on the type of ice, the energy can radiate out from the ship, creating a swath of broken ice two or even three times the width of the vessel.

Once the ice is broken, the shape of Healy’s hull then facilitates turning the ice on its side to make room for the vessel where the ice used to be. This also creates an open area behind the Healy where the ice has been broken into smaller pieces that can be more easily moved aside by another ship – like the tanker vessel Renda.

Healy makes relief cuts in the ice around Renda

Healy makes relief cuts in the ice around Renda 97 miles south of Nome, Alaska, Jan. 10, 2012. U.S. Coast Guard photo by Petty Officer 1st Class Sara Francis.

Weather and ice

When conducting an escort, as with Renda, weather plays a critical role in the successful outcome of the operation.

Perpendicular winds create ice pressure along the sides of the vessels, increasing friction through the ice and filling in the open area created behind Healy quicker than the escorted vessel can sail into it. This process can result in requiring a higher risk, close-in escort to prevent the escorted vessel from becoming beset, or stuck, in the ice.

If Renda does become beset, Healy is able to free the vessel through a series of passes through the ice designed to relieve the pressure on its hull. Typically, Healy breaks a path parallel to Renda’s track to allow the ice pressing on Renda a place to go (principle two, again!). Sometimes the parallel path of both ships is enough to allow the beset vessel to back up into open water and regain momentum in the forward direction. But other times, many passes must take place to get the entrapped vessel moving again.

An unmanned aerial vehicle prepares to take photos and video of ice conditions

Bill Walker, with the University of Alaska in Fairbanks, prepares an Aeryon Scout unmanned aerial vehicle at the Nome causeway Jan. 10, 2012. Walker is using the UAV to gather aerial photos and video of daily ice conditions in preparation for the planned Nome fuel transfer. U.S. Coast Guard photo by Petty Officer 2nd Class Charly Hengen.

Combining art and science

The adage goes the fastest way between two points is a straight line. However, this is not always the case when ice breaking. Most often, the fastest way through the ice is to avoid it by following openings, called leads, in the ice.

To identify leads and areas of reduced ice coverage or thickness, ice pilots use a combination of satellite imagery, ice reports from the National Weather Service, Coast Guard aircraft over flights and, for this mission, a camera-equipped unmanned aerial vehicle. These technical sources of information are coupled with an ice pilots well-developed “seaman’s eye,” reading the contours of the ice to determine the best route. When technical information is not available, the navigator chooses the most direct route, avoiding ridges and following areas of thinner ice coverage.

From high tech satellite imagery to local knowledge and hands-on skill, navigating in ice is truly a combination of art and science.

Click on the image to hear about the mission to Nome from the Healy’s executive officer

Click on the image to hear about the mission to Nome from the Healy’s executive officer, Cmdr. Greg Tlapa.

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  • Larry Lesniak

    Thanks for the detailed information on icebreaker design and operations.  This critical role of the Coast Guard is little known to those of us in the lower 48 who are away from the Great Lakes or other locations in which Coast Guard icebreakers operate.  I commend the command cadre and crew of the Healy for the excellent work they’re doing on an extension of an already long 7 month scientific journey.  As with all Coast Guard officers, enlisted, and civilian staff they have made the safety and well-being of their fellow citizens their highest priority and will certainly succeed in this critical mission.

    Would it be possible to get a current update on the status of the much heavier Polar Sea and Polar Star?  It’s imperative that we as a nation upgrade our polar icebreaking capability and having both of these cutters out of commission seriously degrades our ability to fulfill the multi-role mission of the Coast Guard in both arctic and antarctic regions.

  • Healy Mom

    Thank you for such a well-written, understandable, and informative article about ice breaking and the Healy!  As a parent of a Healy crew member, I have been closely following this journey via the Healy aloft tower cam, Coast Guard photos and videos, and any news I have been able to find on the internet.  I have noticed all the different tracks from the Healy whenever the Renda becomes beset and have become concerned and impatient at all the delays and slow progress.  Your article so helps to understand how slow a process ice breaking can be.  And this understanding and increased knowledge about Healy, its design and capabilities greatly helps to alleviate my worries as a Healy Mom.  Thank you!

  • http://www.facebook.com/profile.php?id=100000307507920 Jennifer Nocerini

    Honorable actions occurring every day…

  • Mgibbs

    Thank you for sharing, I served on the Mackinaw in the early 70s, on the great lakes we escorted ore carriers thru the ice, a slow process for a single icebreakers, hats off the the crew of the Healy on their current mission.

  • Anonymous

    Interesting commentary!  I served as a deck watch officer aboard the USCGC Glacier from 1978-1980 and made 1 AWS as well as 2 Deep Freeze deployments to Antarctica.  As I read about this latest “rescue mission” of the Coast Guard, it brings back memories of being in the “aloft conn” performing the various maneuvers described in the article.
    It also brings in to focus how our nation’s icebreaking capablity has diminished from 5 polar icebreakers in the fleet when I was an Ensign to 1 operational polar icebreaker today- at a time when there is renewed maritime interest in Arctic waters.  We need to be concerned about our capability to respond to new, increasingly international, challenges in the region.  The bitterly cold Alaska winter of 2012 reminds us of this need, and how it contrasts starkly with warm summers when it was possible to briefly patrol Arctic waters in a 378.  Let’s “gut” the 2 Polar class cutters as well as the Glacier and bring them back to the Coast Guard fleet with 21st century technology.  As the article mentions, the “art and science” of icebreaking is ageless.  The hulls of these 3 cutters are solidly capable of performing the same job they were designed to do decades ago.  If the costs of new icebreakers are prohibitive, or leasing is not a viable option, then this option should be given serious consideration.  Otherwise, we may end up in an unfortunate situation someday of having to call other nations to do the job for us!
    Steve Ruta

  • Anonymous

    Interesting commentary!  I served as a deck watch officer aboard the USCGC Glacier from 1978-1980 and made 1 AWS as well as 2 Deep Freeze deployments to Antarctica.  As I read about this latest “rescue mission” of the Coast Guard, it brings back memories of being in the “aloft conn” performing the various maneuvers described in the article.
    It also brings in to focus how our nation’s icebreaking capablity has diminished from 5 polar icebreakers in the fleet when I was an Ensign to 1 operational polar icebreaker today- at a time when there is renewed maritime interest in Arctic waters.  We need to be concerned about our capability to respond to new, increasingly international, challenges in the region.  The bitterly cold Alaska winter of 2012 reminds us of this need, and how it contrasts starkly with warm summers when it was possible to briefly patrol Arctic waters in a 378.  Let’s “gut” the 2 Polar class cutters as well as the Glacier and bring them back to the Coast Guard fleet with 21st century technology.  As the article mentions, the “art and science” of icebreaking is ageless.  The hulls of these 3 cutters are solidly capable of performing the same job they were designed to do decades ago.  If the costs of new icebreakers are prohibitive, or leasing is not a viable option, then this option should be given serious consideration.  Otherwise, we may end up in an unfortunate situation someday of having to call other nations to do the job for us!
    Steve Ruta

  • Tomandmit

    So glad ya’ll are making some headway, hopefully the trip home will be that much easier.

  • Tomandmit

    So glad ya’ll are making some headway, hopefully the trip home will be that much easier.

  • Jademarine

    appreciate info – what happened to ice breaker that used to visit my home town (Erie, PA) in 50′s?

  • Scott (MECM, Ret type)

    Well writen article Kristen… nicely done!

  • Scott (MECM, Ret type)

    Well writen article Kristen… nicely done!

  • LT S. M. Young

     Larry Lesniak,
    Thanks for commenting! Unfortunately, there are no “new” updates for either the Polar Star or Polar Sea. The Polar Star went into a special “Caretaker” status June 30, 2006. In the meantime, you can check out both the ship’s websites for more information: 

    and

    Very Respectfully,
    Lt. Stephanie Young
    Coast Guard Public Affairs 

  • LT S. M. Young

     Larry Lesniak,
    Thanks for commenting! Unfortunately, there are no “new” updates for either the Polar Star or Polar Sea. The Polar Star went into a special “Caretaker” status June 30, 2006. In the meantime, you can check out both the ship’s websites for more information: 

    and

    Very Respectfully,
    Lt. Stephanie Young
    Coast Guard Public Affairs 

  • Katherine Stewart

    Healy Mom, my hubby too is on the Healy and have been closely watching this mission.  This article is very informative and interesting.  This is my husbands second deployment on the Healy and it never ceases to amaze me what the Healy does!! 

  • Katherine Stewart

    Healy Mom, my hubby too is on the Healy and have been closely watching this mission.  This article is very informative and interesting.  This is my husbands second deployment on the Healy and it never ceases to amaze me what the Healy does!! 

  • http://www.facebook.com/aleut.lady Annette Wilson

    Very informative, thanks. I’m from Bristol Bay AK and my brother in-laws co., is the one that is charged w/ delivering the fuel on the Renda. We give you much thanks for crushing your way thru to deliver the much needed fuel to the region!

  • Sadysajo2

    Nice article. Thanks Rick

  • A Bit Lost

    Just saw the story on the news and don’t understand why the Healy treads out a circle around the trapped ship in order for it to move.  you’d expect a straight line…can someone help me understand? thank you.

  • Luan541

    Interesting article on icebreaking. It has been determined by the current government and Coast Guard that the US doesn’t need to waste money on such frivolous endeavors when the same money would buy two cutters giving two high ranking officers needed sea experience and the Caribbean is much warmer than Nome.
    Though the polar caps are melting and more commerce will be by polar routs and there are vast oil reserves recently discovered in the arctic. Russia thinks enough of the importance of the area that they are building 24 nuclear polar ice breakers. Ships are being built by the Canadians, British and Dutch. One can’t help but wonder why we aren’t interested.

  • http://www.facebook.com/people/Andrea-Lynette-Orenduff/1509821401 Andrea Lynette Orenduff

    Be safe. Thinking of the people that are on “all” the ships, the people on the ground assisting and everyone involved. Good Luck and please be safe.

  • ghennigs

    interesting story enjoyed it my father spent several years aboard the Northwind in the late 50′s and made several trips through the northwest passage enjoyed listing to his adventures as a child.  I’m sure he would be proud of the Healy crew as he is of all service men and women another great job by USCG.

  • Sam

    Its my understanding the Healy has 76 crewmembers and up to 50 scientists?  Can you verify that and also, how many crewmembers does the Renda have on board?  Thanks Coast Guard, you rock!

  • LT S. M. Young

    @50ac065c5c88aae107d18f92bf1db71c:disqus ,

    Thanks for your comment. I am not sure what moment exactly you are asking about, but there are many reasons Healy could have been treading out a circle. One of these is to relieve pressure. If the tanker vessel Renda becomes beset – or stuck – in the ice, Healy can free the vessel by performing a series of passes to relieve pressure on the hull of Renda, thus freeing it. 

    Healy could also have been avoiding thicker areas in the ice. Icebreakers may often take paths that are not straight in order to follow thinner ice, or find areas that there are breaks in the ice.

    Hope that helps!

    Very Respectfully,
    Lt. Stephanie Young
    Coast Guard Public Affairs

  • LT S. M. Young

    @c1e0c3bed0583244e3a8c3963bf13f93:disqus ,

    I checked out Healy’s webpage to find some answers for you and under accommodations I found: 

    “19 Officer, 12 CPO, 54 Enlisted, 35 Scientists, 15 Surge, 2 Visitors”

    Hope that helps. If you want to find out more information about the ship, check out this link:

    Very Respectfully,
    Lt. Stephanie Young
    Coast Guard Public Affairs

  • Charter Tschirgi

    Don’t forget water sky and radar. Two other excellent tools for finding leads.