Ice Warriors Raise a Guiding Light Atop the Frozen Deep

By Bob Trapani, Jr.

Buoy encased in ice
USCG Photo

"Old Man Winter" wreaks havoc
with conventional buoys when
waterways freeze over

When December’s winds blow cold and “Old Man Winter” transforms the fluidity of waterways into frozen masses of icy desolation, many different types of lighted aids to navigation (ATON), including the rugged buoy, find themselves succumbing to the lethal force of moving ice floes. Whether piled upon by pancaked ice fields or dragged under the frozen seascape to the “cradle of the deep” by running bergs, exposed lighted buoys stand little chance of holding their station in a manner that is of maximum navigational value under these conditions.

Even lighted buoys that are free of ice floes and able to bounce upon winter’s frigid blue waters remain at grave risk to the debilitating effects of ice. As waves splash against the hull and tower of a buoy during long periods of bitter cold weather, frozen spray accumulates, forming a heavy ice coating that precariously weighs down the floating light.

“Our standard lighted buoys have a lot of angles, cages, towers and the like, and the ice clings to the buoys like smell on roses,” says Chief Warrant Officer Paul Dilger, officer-in-charge of the ABBIE BURGESS, a U.S. Coast Guard “Keeper Class” 175-foot coastal buoy tender, based out of Rockland, Maine. “As the ice climbs higher into the cage, the buoy will lean further over until it is on its side and looking like a big ice cube.”

Buoy coated with ice
Photo courtesy of CWO Paul Dilger

Even buoys in open waters
suffer from ice accumulation during a
typical winter season

Lighted buoys are critical aids to navigation, but if conventional buoys can’t face down “Old Man Winter” in the mariner’s hour of greatest need, what does the Coast Guard rely on to safeguard America’s frigid waterways during these circumstances? The answer is the lighted ice buoy. You might call them the ‘Special Forces’ of ATON, whose sole purpose is to do combat with one of navigation’s most dreaded enemies – ice!

The lighted ice buoy’s very unusual appearance may look a bit strange at first glance, but its innovative design provides these ‘ice warriors’ with tactical advantages when waterways crystallize. Chief Warrant Officer (CWO) Dilger provides an explanation, noting, “The saucer shape of the hull allows the buoy to ride over the ice. There are no sharp edges so the ice is unable to cling to it. If the hull is pushed underwater by the ice, the light tube is all that is sticking up through the ice, and again, there is nothing for the ice to attach to and therefore it usually leaves the lighted ice buoy in place.”

Crewman work with ice buoy
USCG Photo

A Coast Guard buoy tender
crew prepares to place a
lighted ice buoy on station

Petty Officer Mike Hvozda of Coast Guard Public Affairs Detachment New York further points out that “ice hulls and their lanterns are shaped to deflect loose ice floes and sustain prolonged periods of time submerged below an icy waterway and emerge still providing a signal to the mariner.” Petty Officer Hvozda goes on to say, “A conventional buoy in the same situation would be severely damaged.”

Each year from December 1st to April 1st the U.S. Coast Guard deploys the lighted ice buoy in place of certain conventional buoys as advertised in the Light List. At other lighted buoy stations, the decision of whether to switch out to a lighted ice buoy falls to the discretion of the Coast Guard, depending on winter trends and the threat level of ice. According to CWO Dilger, “We have numerous hulls that are advertised as ‘replaced when endangered by ice.’ Many of those hulls may simply be removed to keep them from being damaged or destroyed – or towed to sea by the ice!”

The lighted ice buoy has no place to hide when the irresistible tides begin to carry large fields of ice upon its watery shoulders. Whether standing toe to toe against frozen floes plowing seaward or having to hold station during periods of being completely submerged under water by fields of ice – until it can once again reemerge victorious, the lighted ice buoy is one tough cookie.

Ice buoys
Photo by Bob Trapani, Jr.

The unique design of the lighted
ice buoy might look odd, but
it works like a charm

This winter warrior might not look all that impressive size-wise if you are to observe it floating in the water, but when fully exposed before deployment, it is a massive hulk that presents an almost space-age like appearance. According to the U.S. Coast Guard’s 2005 Aids to Navigation Manual, the lighted ice buoy weighs 6,500 pounds. Overall the buoy is some 20 feet in length, with a hull that possesses a 10’ 7” draft and a steel pillar topped by a light that has a focal height of 9’ 10”.

Its sheer size, innovative construction and durability bode well during its annual battles with ‘Old Man Winter,’ but as the Coast Guard’s ATON manual points out, the lighted ice buoy has a few disadvantages. According to the document, the buoy “is designed with special lighting and battery equipment to survive entrapment under the ice,” but at the same time, “the buoy has no radar reflector and has a very small visual profile.” The daymark visual of a lighted ice buoy is only 1.4 nautical miles.

Crew deploys ice buoys
USCG Photo

The U.S. Coast Guard deploys lighted ice
buoys from Dec. 1 to Apr. 1 each year

CWO Dilger echoes similar sentiments, saying, “The ice buoys have a much smaller radar signature as they are smooth all around and do not show up on the radar as well as a radar reflective buoy. They are also harder to see as the top is rather slender and the main body is low in the water. Until the advent of the LED lights, the old lighted ice hulls were much dimmer than the buoy it replaced.”

Though the mission of lighted ice buoys is paramount to navigation, these ‘ice warriors’ are all but anonymous to the general public, for they disappear from the waters before the recreational boater returns for another season of fun in the sun. But as we all know, the duty of safeguarding mariners never takes a vacation. The hardy souls that ply the frosty seascapes during the long cold season can count on the United States Coast Guard and the services of the lighted ice buoy to show them the way when desolation and fields of ice are their only companions along their arduous way.

Interesting Lighted Ice Buoy Facts:

  • Definition of a Lighted Ice Buoy (LIB): A lighted buoy without a sound signal, and designed to withstand the forces of shifting and flowing ice. Used to replace a conventional buoy when that aid to navigation is endangered by ice.
Ice buoys
USCG Photo

Prior to LEDs, lighted ice buoys were
equipped with a polycarbonate dome that
protected the incandescent lighting system

  • The official Coast Guard designation or acronym for the lighted ice buoy is 7X20LI.
  • Prior to LEDs becoming the optic of choice for lighted ice buoys, the Coast Guard utilized a modified 155mm incandescent optic and CG-181 flasher that was protected from the elements by a polycarbonate or Lexan dome. According to the 2005 U.S. Coast Guard ATON Manual, “Ice buoy domes protect the lanterns on lighted ice buoys. The clear polycarbonate plastic domes are installed with a gasket kit and support ring to provide a watertight seal.”
  • “Crews working on Coast Guard buoy tenders and Aids to Navigation Teams have been switching conventional buoys with ice hulls for years. There are as many as 306 ice-hull buoys replaced annually, but some are only changed out if endangered by ice. The LED ice buoy lanterns were first tested in 2002 as prototypes in the Chesapeake and Delaware Bays, installed on a limited basis late in the ice season of 2003 and them completed as a full conversion this winter (2005). – From the Coast Guard Press Release Moving Forward into the Ice Age by U.S. Coast Guard Petty Officer Mike Hvozda, January 24, 2005
Sabik MPV-LED atop ice buoy
Photo by Bob Trapani, Jr.

A close-up view of the
Sabik MPV-LED that serves as the
lantern atop a lighted ice buoy

  • When LEDs replaced the traditional incandescent lighting apparatus, it not only improved the visibility of the light itself but the optic’s overall durability as well. According to Captain Paul Dilger, “The old polycarbonate dome and ‘standard’ lampchanger are gone. They suffered greatly from vibration caused by ice. Often all of the standard lamps would rotate out of the lamp changer or just disintegrate due to the constant vibration. The new LED lights are much brighter and certainly more ice resistant.”
  • The LED utilized as the standard lantern for lighted ice buoys is an MPV-LED, which is manufactured by Sabik of Finland. In addition to possessing light emitting diode technology, the MPV-LED also sports ice resistant housing, which eliminates the need for a Lexan ice dome, and is extremely durable and power efficient. The LED also produces uniform light output down to 10 VDC and has a Daylight control built-in to the lantern. The LED is powered by a 320 AH ice buoy battery.
Crew works on buoy deck
USCG Photo

A lighted ice buoy is placed on
station for the long, cold winter season

  • According to the U.S. Coast Guard ATON Manual, the Sabik MPV-LED is 4-inches tall, 12-inches in diameter and weighs approximately 35 pounds. A fixed LED lantern displays a red, white, green or yellow light 5 nautical miles. Flashing LED lanterns show a light for an average range of 4 nautical miles.
  • When it comes to servicing the LED lantern, the U.S. Coast Guard Aids to Navigation Manual notes, “Servicing is not necessary during a routine ice season. Based on past performance, the operating temperature and the drive current of the LEDs, this lantern can remain in service for 20 ice seasons (possibly longer) if the lens and housing are still in good condition.”
Lighted ice buoy
USCG Photo

Lighted ice buoys are the
"Special Forces" ATON
deployed to combat one of
navigation's most dreaded
enemies -- ice!

Lighted ice buoy in fights ice floes
USCG Photo

Lighted ice buoys stand and
fight against the onslaught
of moving ice floes

USCG Safeguards America's waterways
USCG Photo

The U.S. Coast Guard safeguards America's
waterways through ice, storm and calm

Created: September 2006