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U.S. Coast Guard Icebreaker Mackinaw

Engineer Officer Kevin Asbury stands on the bridge of the Mackinaw for nearly the last time as he closes in on retirement and prepares for a new life with his family in Southern Illinois.

Everyone who lives on or near the Great Lakes is familiar with the silhouette of ships and boats seen on the horizon. Some of us can even distinguish the difference in the larger ships ? this one being an ore carrier, that one being a grain carrier? But for over 58 years everyone unmistakably recognizes one ship's silhouette. It is the "Mac", the "Guardian of the Lakes", the "Great White Mother" and a half dozen other nicknames she has been fondly called. This is the Coast Guard's heavy icebreaker, "Mackinaw".

In October of 2001, the Coast Guard awarded a contract to the Manitowoc Marine Group in Wisconsin to build a new icebreaker. Scheduled for delivery in 2005, the new ship will replace the "Mac" which will leave the Coast Guard for a fate as yet unknown. So the final curtain has begun its decent upon that venerable old friend that has served her country and the Great Lakes so well. Thus, the Chief Engineer thought it a good time to visit with this remarkable ship and the remarkable people who helped her forge a legend on the "Lakes"; a legend that will remain long after she fades from the horizon.
The beginning of our story has to be at the beginning of the Mac; and that takes us back to 1944. The Second World War was still being furiously fought both in Europe and in the Pacific. Although then the outcome of the conflict was still in doubt, there was no doubt that victory, if it came, would be brought about not solely from the blood and sacrifice of America's fighting men, but also from our nation's ability to equip and arm those doing the fighting, with the necessary weapons of war.

All along the coastal shores of the Great Lakes, industry worked ceaselessly for the war effort. The mills of Chicago and Gary rolled from their furnaces the raw steel that would be fashioned into components for ships, tanks, aircraft, and thousands of other products, vital for any hope of winning and ending the conflict. Fueling those furnaces of industry was coal from Pennsylvania and producing that steel was ore mined in Minnesota. The best method for delivering that coal and ore was the great natural resource known as the Great Lakes. And so, from their ports in Erie and Duluth, the ore carriers and coal carriers would come, filled with the fuels and natural resources necessary to keep the great mills working. And from the ports in Chicago, Gary and Hammond flowed the finished products for war and the grain to feed a hungry world.

But one natural obstacle threatened the steady flow of all these vital necessities. That obstacle was ice. From mid December until mid April, ice forms in the very ports necessary to provide these vital supplies. Starting its formation near the shoreline, the ice spreads outward into the lake. Sometimes, if the winter is especially harsh, an entire lake can freeze over. The last time this happened was during the winter of 1993-1994 when all of Lake Superior was covered with ice. A look at a map of the Great Lakes will quickly illustrate a second Great Lakes ice problem. To move commodities from any one of the Great Lakes to another, a relatively narrow passage must be taken. For example, to move from, or to Lake Michigan, requires passage through the Straits of Mackinac; to, or from Lake Superior, requires a trip through the St. Mary's River. In these relatively narrow points, ice quickly forms, and many ships can quickly become ice bound ? or worse.

The War Department clearly understood the vital need to keep ice from slowing the industrial war effort. Funds were quickly authorized for the construction of a heavy icebreaker, built specifically for service upon the Great Lakes.

At the Toledo Shipbuilding Company in Toledo, Ohio, the beginning of what would become a legend began to take shape. From the beginning, the designers knew they were not just creating a new icebreaker, but an entirely new class of icebreaker. Beginning with the massive keel, they knew that the Mackinaw would have to accomplish in one pass, what smaller ice breakers had to make in 3 to 4 passes to accomplish. This meant a beam (width) wide enough to make a path through ice that the largest ore carrier or freighter could easily steam through. At more than 74 feet, the Mackinaw is as wide as most of the vessels on the Great Lakes are long. And with her massive length of 290 feet and a displacement of 5,252 tons, her designers knew that the power needed to carry her safely through the heaviest ice, would have to be as massive as her size.

For the propulsion systems prime movers, the marine engineers selected six, 2-cycle, Fairbanks Morse diesel engines. Two of the engines reside within one on the three watertight compartments that were designed below deck. Theoretically, if catastrophe struck, the Mackinaw could lose four of her engines to flooding and still bring her crew home. Each of the 10 cylinder diesels produces 1,750 continuous Horsepower and has a 4-hour rating of 2,000 Hp. The cylinders of the diesels have an 8-1/8 inch bore and 10 inch stroke. The engines are rated at a continuous 750 Rpm with a 4-hour rating of 810 Rpm. An air system is used to start the engines.

The sole purpose of these six massive engines is to generate electricity. Probably surprising to most "landlubber" Chief's, is the fact that the Mackinaw is technically an electrically operated ship! Equipped with 6 Westinghouse generators rated at 1,375 kW each, the Mackinaw diesels supply the power for the generators that in-turn, supply power to electric motors that turn the shaft and propellers of the vessel. The 900-volt DC generators turn at 810 Rpm and are shunt-wound. 5kW of excitation is required per generator at 250 volts. Excitation comes from three motor generator sets, 1 located in each motor room. The gen-sets are driven by AC motors and must be powered by at least one of the auxiliary service engine-generators, which are the only source of AC power aboard the ship.

Current flowing from the main generators feed to the 3 main propulsion motors. One motor is located forward near the bow (front) of the ship; the other 2 are located near the aft (rear) section. These motors work the three shafts that are coupled to the 3 propellers of the ship. Two propellers are in the aft and one is in the bow. That's right! The Mackinaw is equipped with a propeller in her bow! Besides maneuvering her out of tight spots, the bow propeller has the power to "mill" ice into a safe, thin slush for the ships that follow, in the path the "Mighty Mac" makes.

The aft Westinghouse DC propulsion motors are rated at 5,000 Hp each and operate at 900 volts, turning at up to 170 Rpm. The forward Westinghouse DC propulsion motor is rated at 3,300 Hp and operates at 900 volts, turning at up to 200 Rpm. All three motors are shunt-wound. 9.7 kW of excitation is needed for the forward motor and 5 kW is needed for excitation of the aft motors. There is no gear reduction between the motor and the shaft. If the motors are running at 200 Rpm, the "screws" (propellers) are turning at 200 Rpm as well.

So how does the "Mac" speed up or slow down? A potentiometer rheostat that governs the flow of current from the propulsion generators to the propulsion motors accomplishes that. If you want to speed the ship up, you increase the current flow to the motors.

The diesels on the Mackinaw can handle up to 75% of the generator output while at idle speed of 400 Rpm. If more speed is needed, the diesels will slowly increase speed to their maximum of 810 Rpm, allowing full output from the generators to the propulsion motors. To reverse the rotation of the propellers, polarity through the motor windings is reversed.

Control of the propulsion system is accomplished through a pneumatic control system operating from 0 to 60 psig. The pneumatic control system operates actuators that vary the potentiometers input. A control demand for more speed results in an increase in current flow to the propulsion motors and, as a result, more Rpm from the shaft.

Control panels are located in both the engineering section of the ship and in the pilothouse. There are two ships wheels for steering the ship as well. One ship's wheel is found in the pilothouse and another located in the steering section, well below and aft in the ship. Hydraulic pumps, located in the aft steering section of the vessel move the massive ships rudder. This redundancy, engineered into the Mac by her designers, allows for complete operation of the vessel from the pilothouse, or from below in the engineering and steering sections of the ship.

When moving through ice, the most vulnerable area on an icebreaker is its rudder. A propeller can quickly mill chunks of ice, but if they strike hard into the rudder, the ship could lose its ability to steer. To assist in protecting the Mackinaw's rudder, a "horn" was incorporated into its design. This horn, which extends forward from the rudder. Helps "cut" through ice chunks, keeping them from impacting upon the rudder. During operation, keeping the rudder amidships (straight) also helps to protect it from impacts upon its more vulnerable sides.

Besides the tremendous power incorporated into an icebreaker, the strength and design of her hull must be such as to not only withstand the impact of hard ice, but to crush and bust the ice it encounters without sustaining any damage. The principle behind breaking ice is to not simply have the hull of the shop ram into it, but to allow the bow to rise from the water atop the ice and then allow the massive weight of the ship to crush down upon it. While the rising bow is accomplished through the design of her hull and power from her propellers, the crushing blow to the ice comes from the sheer strength of her body. With a forward hull (ice plate) made of 1-5/8" thick steel and her steel ribs spaced just 16-1/2 inches apart, the Mackinaw was designed to have the strength to continuously move through ice of up to 3 feet in thickness at a speed of 3 knots (3.45 miles per hour).

The Mackinaw's designers fully intended her to be the workhorse she became. Designed with a range of 41,000 nautical miles (47,150 land miles) at her cruising speed and 10,000 nautical miles (11,500 land miles) at her top speed of 19 knots (21.85 mph), the Mac was meant for extended sea duty.

To ensure the Mackinaw was able to respond to most crises that may arise, the Marine Architects and Engineers designed the Mac with the ability to tow large ships. Notched into the stern of the Mac is a "V" that will accommodate the bow of another ship. A large towing motor is installed below the stern deck and equipped with a 1-1/2 inch steel cable. The idea was to allow the Mac to pull a ship directly into the "V" and in tandem the Mac and the towed vessel could proceed through the ice.

HVAC aboard the Mackinaw is accomplished with 3 electric boilers. The 150 kW boilers generate 15 psig, saturated steam, which is fed into heat exchangers to accommodate the hot water heating system. On the coldest of days, only 2 boilers are needed to keep the Mac's crew comfortable inside the ship. Six blowers provide ventilation throughout the ship, with duct coils tempering the air temperature. Three, 85-gallon, electric hot water heaters, rated at 100 Gph each, provide hot water for the crew.

Although the engineering design of the shop seems flawless for her time, one headache for the engineering crew comes from the lighting system. During ice breaking operations, considerable vibration is felt throughout the ship. This vibration tends to take a toll on the ship's fluorescent lighting system. Engineering personnel reportedly go through as much as 4 cases of fluorescent bulbs each month during the ice breaking season.

As packed with the tremendous power and utility the Mackinaw has, the most significant thing about her design and engineering is her appearance. No doubt about it, the Mackinaw is a beautiful ship. One look at her sleek lines turn all who see her into admirers. The "Lady of the Lakes" is yet another nickname penned on the Mac, and for sheer beauty and style, that name is most appropriate.

Slipped from her christening dry dock in 1944, the Mackinaw has witnesses much in her duty upon the Lakes. She has served to train sailors from other nations, forged countless paths through treacherous ice, assisted in search and rescue operations and officiated at countless regattas and special events. From the beginning her homeport has been Cheboygan, Michigan. Positioned at a key point near the narrow Straits of Mackinac, she responds to duty throughout the upper Great Lakes.

As the Chief Engineer boarded the Mackinaw, Zack Ford, the Public Information Officer for the Mackinaw, greeted us. Zack made the arrangement for our visit and made the first lasting impression on us about the U.S. Coast Guard as an efficient and highly professional naval service. It isn't easy to facilitate visits to the Mac during the ice season much less to accommodate a journalist who wants to climb through the engineering spaces of a working ship. But Zack made everything seem easy and we are deeply indebted to him for all of his hard work.

Zack ushered us into the Officers Ward Room where we first met with Lieutenant Commander Kevin Asbury, the Engineer Officer of the Mackinaw. Unlike the U.S. Navy and Power Engineers in general, the U.S. Coast Guard does not use the term "Chief Engineer". With 24 years of experience and more than 10 years of "sea duty", Asbury is retiring from the Coast Guard to take up residence in his home town near Carbondale, Illinois. The Chief Engineer was honored therefore, to have the opportunity to interview this remarkable man who serves such a remarkable ship.

As we first sat talking, Asbury seemed somewhat uncomfortable with being interviewed. But as soon as we began our tour of the engineering spaces of the ship, we were reintroduced to this Engineer Officer. To put it in terms that Chief Engineers would understand, Asbury is that kind of engineer whose heart beats in time with the pulse of his ship.

As we maneuvered down ladders and squeezed through small hatches, descending deeper and deeper into the Mac, Asbury became noticeably more comfortable. It didn't take long for us to realize that this Engineer Officer was actually sizing us up. At some point in our excursion, I guess we passed muster, because we stopped being interviewer and interviewee and became two engineers talking about what we love.

As we came to a stop in the lowest part of the ship near the bow, we asked him what he would miss most about leaving the Coast Guard. After a slight hesitation, he looked away and said it would be breaking the ice. "When she (the Mac) is out there", he said, "running through that ice, there is nothing like it in the world." As he spoke, we watched his eyes as they stared far away, and realized that at that moment, he was out there on that ice. And, that a part of him always would be.

Two weeks out of high school, Asbury entered the Coast Guard Academy in New London, Connecticut. Four years later he graduated with a degree in Marine Architecture and Engineering. His first assignment was as a deck officer upon a Coast Guard cutter in Alaska. After 3 years he entered the Coast Guard's Student Engineering Program followed by shore duty in Cleveland. He assisted in the Coast Guards establishment of two engineering support groups, one on the West Coast and the other on Governors Island off the East Coast.

He then transferred back to sea duty as Engineer Officer aboard the cutter Vigilance until she was decommissioned, and then on the cutter Reliance, both sailing from homeport out of New Castle, New Hampshire. Eventually he requested and received a transfer to the Great Lakes. Married with a 1-year-old daughter, Asbury told us they were the main reason behind his decision to retire from the Coast Guard.
Aboard the Mackinaw, Asbury supervises a staff of 34 men and women who are responsible for the day-to-day operation of the ship. His biggest challenge he told us, was being left to his own ingenuity and resources while the ship was at sea. "When you're 100 miles out," he said, "You have to make the ship work".

We asked him what advice he would give to young men and women who might be considering a career with the Coast Guard. "Set your goals high", he said. "You can go as far as you want, as fast as you want".

"Would he miss the Mackinaw?" we asked. "Sure", he replied. "This ship is so dependable, the Lakers (Lake carriers) have come to expect us". "When other newer ships are down in port, we're always out there breaking ice".

In command of the Mackinaw is Commander Jonathan Nickerson. A graduate of the Coast Guard Academy's class of 1984, Nickerson assumed command of the Mac in July, 2000. A normal command tour is two years, Nickerson has had his tour extended for an additional year.

He told us that his greatest challenge as Commander of the Mackinaw was keeping the crew ready for duty. Since September 11th, the crew has been at a higher state of readiness, with primary concern being the protection of the vessel. Because of normal rotation of duty, a 50% annual turnover rate is normal for the crew. Along with the fact that 90% of the training enlisted personnel receive in the Coast Guard is on-the-job, following just 8 weeks of basic training in Cape May, New Jersey, it's easy to see that command of the Mackinaw is a 24/7 commitment.

Low pay also poses a challenge for Coast Guard personnel. According to Commander Nickerson, the starting salary for enlisted personnel is less than $1,000 per month, so all but a small handful of the entire crew qualifies for some form of financial assistance.

Nickerson explained to us some of the reasons for the decision to decommission the Mac. Besides her age, she is only capable of being out to sea for 5 days. When she was built, Nickerson explained, ships would eject waste directly into the sea. Since then, environmental regulations ban such practice. So now all waste has to be stored in tanks and pumped out in port. The Mackinaw was simply not designed for such a thing. In addition, modern ships can operate with a crew of less than 20 persons, while the Mackinaw presently has a crew comprised of 11 officers and 80 seamen. Finally, there is the fact that the Mackinaw was only designed for one thing ? icebreaking. A modern ship can perform multiple tasks.

Nickerson went on to say that the new vessel being built to replace the Mac would also be named Mackinaw. What would happen to the present Mac, he was not sure. Traditionally, he said, a friendly nation that petitioned the United States and demonstrated a need would have preference in receiving a retired vessel. But in the case of the Mackinaw, there are already private U.S. citizens that have expressed a desire to obtain the Mackinaw for a floating museum or tour boat. Ultimately, he concluded, Congress would decide the fate of the Mac.

In his little spare time Commander Nickerson likes to be with his wife and son, 11 and daughter, 8. An accomplished artist, who has previously sold some of his oil paintings, Nickerson confessed that he simply hasn't been able to pick up a paintbrush since assuming command of the Mackinaw.

Asked what advice he would give to those contemplating a career with the Coast Guard, Nickerson said that if you recognize yourself as a good person, with a desire to serve your country and your fellow citizens, then the Coast Guard could be a good career choice.

As the Chief Engineer left the Mackinaw, it was with mixed emotions. We bid farewell to a great ship but we came away optimistic about the future of the Coast Guard and her presence upon the Great Lakes. With so many young men and women, eager to serve their country and those of us who live upon the Lakes, and with dedicated professionals like Lieutenant Commander Asbury and Commander Nickerson, we recognized that as the Mackinaw slips from the horizon, we will see the coming of a new ship and a new crew, eager and ready to create another legend on the Lakes.

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