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    Past and Present Coast Guard Vessels for the Arctic

    Encyclopedia Arctica 9: Transportation and Communications

    001      |      Vol_IX-0168                                                                                                                  



    Captain Edward H. Thiele, USCG

            With the advent of U.S. Revenue Cutter Service (Coast Guard) operations

    in the Arctic it was apparent that a special type of craft would be necessary to cope

    with the problems of extreme cold weather, ice and operations in remote sparsely

    inhabited areas. Because of the lack of experience in this type of operation, the

    logical solution was arrived at by investigating the types of ships then in existence

    and plying these remote areas.

            At that time whaling and sealing in the polar regions were in full swing,

    and through bitter experience a type of vessel had been developed that would with–

    stand the rigors of arctic navigation within the limits of the facilities available.

    It was common practice, especially with whalers, to make cruises into the Arctic of

    several years duration, freezing in during the winter months — sometimes purposely,

    other times unavoidably. As a result of this type of operation, the hull form, construction

    and means of propulsion were governed by the probability of becoming ice-bound and

    being caught in heavy squeezes.

            The U.S. Navy had acquired two special type craft, which had originally

    been constructed as arctic sealers, for use as relief vessels in connection with the

    ill-fated Greeley expedition. After the successful completion of several missions to

    the Arctic under the Navy, these two vessels, the Bear and Thetis , were transferred to

    the "Revenue Cutter Service" in 1885 for patrolling Alaskan territorial waters.

            The construction of these two vessels was modern and in accordance with the

    best practices of the period, and proved to be highly successful for the duty in

    tended. The hulls were built in Dundee, Scotland, by A. Stevenson and Sons, about

    1874, and the boilers and machinery in Greenock, Scotland, by the Greenock Boiler and

    Iron Works. Details, showing the inboard profile and midship section, are shown in

    Figs. 1 and 2. The vessels were similar. The characteristics of the Bear were as


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    Length over all 198' 0"
    Beam molded 28' 6"
    Draft (maximum) 18' 2"
    Displacement tonnage 1,700
    Main propulsion Reciprocating steam
    Power 350 IHP
    Auxiliary propulsion Sail
    Rig Barkentine
    Hull Wood
    Keel American Elm, 14 1/2” x 14 1/2”
    Frames German Oak, 12” x 14” (Approx.)
    Frame Space 16 1/2” (Approx.)
    Bottom planking Elm, 4 1/2”
    Side planking Pitch pine, 5 1/4”
    Inner planking Pitch pine, 4”
    Ice sheathing Iron bark doubling, 2 1/2”

            By the 1870's it was recognized that power was essential to work in northern

    waters, but the possibilities of losing or damaging the propeller or rudder, if caught

    in the ice, were ever present. With no assistance available and no communications,

    the only solution in case of underwater damage was to rely on sail. No ship would

    dare enter the A rotic without two sets of sails (one spare).

            The Bear was operated by the Coast Guard in arctic waters from 1885 to

    1926. In 1927 the Coast Guard built the Cutter Northland (Figs. 3,4) to replace her.

    The Bear had proven satisfactory for routine Coast Guard duties during her many years

    service in the Bering Sea, and so, naturally, many of her characteristics were incorp–

    orated in the Northland . The principal characteristics of the Northland were:

    Length over all 216’
    Beam, molded 39’
    Displacement at 15 Ft. mean

    2,050 tons

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    Number of main propulsion

    diesel engines
    Total shaft horsepower 1,000
    Speed, knots 11.5
    Auxiliary propulsion Sail
    Rig Barkentine
    Builder Newport News Shipbuilding Co.,

    Newport, Va.

            Although the Northland had some of the same general characteristics as her

    predecessors, the Bear and the Thetis , many improvements were embodied in her design.

    The massive wooden hull of the earlier ships was replaced with steel. Special

    attention was given to providing hull strength to withstand the crushing forces of ice

    and to limit flooding in case of hull damage. The waterline plating of the hull varied

    from 1-1/4” thickness at the bow to 1” thickness at the sten. Other strakes of

    plating varied in thickness from the maximum of 1-1/4” to a minimum of 1/2”. It was

    expected that this plating would be sufficiently heavy to resist the abrasive and

    tearing action of ice which this vessel might normally be expected to encounter. The

    vessel was of riveted construction and was subdivided by nine transverse watertight

    bulkheads. In addition to the function of limiting flooding, these transverse bulk–

    heads were designed as strength members and contributed towards the vessel's ability

    to withstand crushing.

            The Northland was built with a typical (European type) cut-away bow that had

    been successfully in arctic operations by other nations. Although the Northland could

    break light ice, she was not built primarily as an ice-breaker. She was built with

    sufficient strength to withstand the contacts with ice accompanying navigation in

    fields of broken ice; and with sufficient endurance to permit operating away from a

    base for long periods of time, and to give the crew a reasonably good chance of sur–

    viving until the thaw, should the vessel become entrapped.

            Although great strides had been made in the design of machinery and

    materials, navigators were still reluctant to take a ship into arctic ice without

    004      |      Vol_IX-0171                                                                                                                  
    sails as an auxiliary means of propulsion. As a result, the Northland was rigged

    as a barkentine ship to satisfy the old line experienced arctic skippers. In the

    process of changing from wood to steel ships the propulsion machinery was given

    intensive thought and study. The advantage of diesel economy was recognized, but

    a means of providing rapid maneuverability and protection for the propeller and main

    engines was desired. After weighing all factors it was decided to adopt diesel

    electric drive, and as a result one of the first successful installations of this

    type was made. As an added precaution to protect the propeller and the main motor,

    an electromagnetic coupling was installed in the line shafting between the main motor

    and the propeller. This feature was later eliminated when it was found that the

    coupling would throw out in a sea-way when the propeller broke water.

            The reliability of the main power plant was of utmost importance. The refore

    two main generators were employed, supplying current to a single double-armature motor.

    In this manner it was possible to provide two independent sources of power to a

    single propeller, thus increasing the reliability of the motive power. We note that

    in all modern arctic vessels this principle of multi units has been adopted.

            Although aviation was still somewhat in its infancy in 1926, the specifications

    for the Northland included a boom for hoisting a seaplane to the after deck. A sea–

    plane was not operated from this vessel to any great extent until World War II, when

    the Northland was used on patrol duty off Greenland, nearly twenty years after she

    was built.

            The Northland proved herself a worthy successor to the Bear , and was used

    in arctic operations from 1927 until 1946. The Northland was designed for extended

    cruises into the Arctic and for work in broken ice fields, but it was never intended

    that she should be able to break or force leads into heavy ice. The Coast Guard

    subsequently built several other vessels with ice operating features, including the

    Calumet Class (1934-1935), and six vessels of the Escanaba Class built during the

    period from 1931 to 1935. Much was learned from the ice operation of these vessels

    in regard to the desirability of various types of propulsion machinery, the design

    precautions necessary to insure proper operation of the machinery in ice, and the

    005      |      Vol_IX-0172                                                                                                                  
    the structural effects of ice operations upon the hull.

            Coast Guard experience in the Arctic indicated the desirability of having

    vessels designed not only for operating in ice, but also capable of breaking ice. A

    study of the entire problem was instituted in 1937, including a review of all of the

    date obtainable on the characteristics andperformance of all of the ice-breakers ever

    built. A representative was sent to Europe to inspect and gather information on ice–

    breakers built for the Soviet Union, Sweden, Denmark and Holland. Investigations were

    made to find the most effective hull form for breaking ice, and to develop the proper

    relation between displacement, hull strength and horsepower. Also, all available in–

    formation on actual operating experience was reviewed. The results of this study were

    incorporated into the design of a group of 110’ harbor cutters built in 1939. These

    small vessels were eminently successful as ice-breakers, so many of their characteristics

    were included in a group of 180’ buoy tenders built in 1941, and in the Storis , a 230’

    vessel built in 1941 for operating off Greenland.

            The culmination of this series of vessels was the Wind Class (Figs. 5-6),

    the first of which was completed in 1944. Some features of the early Northland appear

    in the Northwind and her smaller prototypes. All of this series of ice-breakers are

    powered by multiple-engine direct current diesel electric plants. This type plant

    offers economy in space and fuel consumption, flexibility of operation, and dependability.

    It also makes possible the use of pilot house control to permit fast and accurate

    maneuverability while working in ice, thereby minimizimg the possibility of damage. The

    magnetic clutch used on the Northland was not used on these later ice-breakers, but

    main motors of a light weight high capacity type have been used in order to reduce the

    rotating mass attached to the propeller.

            The general characteristics of the Wind Class vessels are as follows:

    Length over all 269’
    Maximum beam 63’ 6”
    Normal draft 25’ 9”
    Normal displacement, tons 5,300 0

    006      |      Vol_IX-0173                                                                                                                  
    Speed, knots 16
    Propulsion Diesel-electric
    Number of main propulsion

    diesel engines
    Total shaft horsepower,

    Number of Propellers 3
    Builder Western Pipe and Steel Co. of California

            The use of double bottoms and wing tanks for fuel has been incorporated

    in the larger recently-built ice-breakers. This provides protection from hull rupture

    and also makes it possible to utilize every available bit of space for the great

    quantity of fuel necessary for long periods of operation away from a base at full–

    power operation, and for surviving long periods of immobilization if entrapped in ice.

            The most outstanding feature of thw Wind Class is the hull form. Hulls of

    the same relative type had proven fundamentally sound by experience gained with the

    110’ Harbor Cutters and the 180’ Buoy Tenders. This hull is characterized by a cut–

    away bow, and bow sections having a great amount of slope. These sloped sections cause

    the buttocks to provide an angle of attack the same as the cut-away bow, and make it

    easier for the vessel to ride upon the ice. The design also causes the breaking force

    to be distributed over the entire forebody of the ship, and not concentrated at the

    forefoot, as would be the case with more conventional lines. Since a vessel must

    sometimes be backed into ice, the hull lines aft are very similar to the fore part of

    the ship. The after propellers are kept as low as possible and in close to the hull

    for protection, and the rudder stock is protected by a heavy cast fin, so constructed

    as to give a breaking angle aft similar to the bow. There must be a very definite re–

    lationship between the transverse strength of the vessel and the angle of flare of the

    midship section, so that, in case the vessel is caught between ice floes, it will be

    lifted before it is crushed.

            The hull of the Wind Class is of all-welded construction, as was the case

    with the smaller prototypes. Due to the use of extremely heavy plating and structure,

    some unusual welding problems developed. The shell plating is of high tensile steel,

    007      |      Vol_IX-0174                                                                                                                  
    varying in thickness from 1-1/4” at the keel to 1-5/8;” at the ice belt. This plating

    is backed up with truss type transverse frames spaced on 16” centers, capable of giving

    a uniform panel strength throughout the hull. The transverse strength is obtained by

    making the decks and bulkheads strength members.

            These vessels are designed to operate in temperatures as low as minus 50 degrees

    F. The entire hull and superstructure above the waterline is insulated with 5 inches

    of cork, and provision is made for isolating the central portion of the ship as winter

    quarters in case of a freeze-in. Also, some provision had to be made for the removal

    of ice forming topside. Such ice may be removed by chipping or by thawing with warm

    water. A large supply of warm water is provided for this purpose by utilizing the

    cooling water discharged from the main and auxiliary engine heat exchangers.

            Experience has shown that, in successful ice-breaking and ice-working

    operations, a means must be provided for freeing the ship if it becomes wedged into the

    ice. On smaller vessels it is customary to roll the vessel by swinging the rudder, but

    in the case of the larger ships other means must be provided. The Wind Class ships are

    constructed with heeling and trimming tanks. The heeling system permits the shifting

    of 240 tons of water ballast from one side of the ship to the other in an 80-second

    cycle, thus inducing a rolling motion of about 8° form the vertical and preventing the

    skin of the hull from freezing in if the vessel is stopped by the ice. The trimming

    system permits the shifting of water ballast (120 tons) between the fore and after peak

    tanks, thus giving a change of trim of approximately 5 feet.

            The underwater appendages of an ice-breaker are very susceptible to damage

    by ice, and propellers are a problem that require particular attention. Single screw

    vessels provide the most protection, because of the position of the propeller on the

    centerline behind a skeg, but the amount of power that can be absorbed is limited. Of

    necessity, the diameter must be kept small to permit broken ice to pass over the blade

    tips. On small vessels a single propeller is used in all cases, but on larger vessels

    the power is distributed between two or more propellers. At present there are two

    distinct types of ice-breakers in general use. The "European Type" consists of a

    cutaway crusher bow, with all power being applied to propellers aft. The "American

    008      |      Vol_IX-0175                                                                                                                  
    Type" consists of a cutaway crusher bow, but with a propeller forward as well as

    propeller or propellers aft. The latter type was developed on the Great Lakes during

    the nineteenth century. Both the "European" and "American" type vessels have distinct

    advantages, depending on the operation to be undertaken. The "European Type" is best

    suited when working alone in extremely heavy ice such as is encountered off the East

    Greenland Coast. Forcing leads through heavy ice floes is known as "ice working." The

    "American Type" is far superior for straight "ice breaking" and for convoying other

    vessels through ice where the ice-breaker must work without benefit of leads. This,

    of course, can only be done in ice which is not beyond the breaking capacity of the ice–

    breaker. In the case of the Wind Class vessels the two types have been combined, in

    that the bow propeller can be installed or left off as operational requirements dictate.

            Propellers of the Wind Class vessels are solid nickel steel construction.

    The after propellers are designed to give the ma x c imum thrust while the vessel is in the

    stalled position. The forward propeller is used as a low efficient pump for dredging

    ahead of the vessel or for creating a wake along the skin of the hull to wash broken

    ice clear. No a ttempt is made to protect the bow propeller except by placing the tips

    of the blades as far below the water li n c e as possible and keeping it well clear of the

    ice-hull contact points. Provision is made for the removal of the bow propeller and

    capping the bow tube when it is anticipated that the vessel will be sent into the high

    Arctic where ice-breaking is impossible and where only ice working can be expected.

            Power for the three propellers is furnished by six 2,000 h.p. diesel engines.

    The power from these engines may be divided between the after shafts, giving 5,000 shaft

    horsepower on each after screw, or it may be divided between the three shafts, giving

    3,300 shaft horsepower each. Quick maneuverability is considered an essential in ice;

    therefore, all modern arctic vessels are provided with pilot house control of the main


            It has been found from experience with Coast Guard ice-breakers that assisting

    other vessels through ice frequently terminates in a towing job. Accordingly, the ice–

    breakers of the Wind Class are provided with very rugged towing equipment. A 40-ton

    009      |      Vol_IX-0176                                                                                                                  
    automatic electric towing machine is provided with 300 fathoms of 2-inch steel towing

    hawser. These vessels tow in open water in the customary manner, utilizing a long

    hawser, but when towing in ice, an ice-breaker, when suddenly stopped by a hummock or

    pressure ridge, is likely to be run down by the vessel being towed. To avoid such

    difficulty the Wind Class vessels have a notch in the stern, so that the towed vessel

    can be hauled in tight to prevent overriding and to keep the vessel in the clear water

    directly astern. This arrangement offers an additional advantage, in that the extra thrust

    from the vessel coupled astern may be used to assist in breaking ice.

            Regardless of the size or strength of vessels built for arctic operations, it

    is always the best and safest policy to pick leads where the ice is easiest to negotiate.

    Planes used for reconnaissance are of inestimable value in this respect, and, therefore

    all arctic vessels of a size permitting stowage are equipped for this type of equipment.

    The Wind Class vessels are now provided with helicopter landing platforms. These

    rotary wing planes are ideally adapted for ice reconnaissance and require no pen water

    for take-off or landing.

            Looking into the future of arctic operations and ships to accomplish this

    mission, the experience being gained in the development of stronger hulls and more

    powerful machinery indicates that eventually a type of craft will be devised that will

    be able to negotiate most of the water-borne obstacles imposed by nature. To this end

    the Coast Guard is committed in it responsibilities established by law as the protectors

    of life and property at sea.

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    [U.S.R.C. THETIS]

    Unpaginated      |      Vol_IX-0178                                                                                                                  

    In board profile U.S.R.C. "THETIS"

    Thiele Fig 1

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    [U.S.R.C. THETIS]

    Unpaginated      |      Vol_IX-0180                                                                                                                  

    Mid ship Section U.S.R.C. "THETIS"

    Thiele Fig. 2

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    Unpaginated      |      Vol_IX-0182                                                                                                                  


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    Midship Section U.S.C.G.C. "Northland"

    Thiele Fig. 4

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    Unpaginated      |      Vol_IX-0185                                                                                                                  

    Inboard profile U.S.C.G.C. "North wind" "East wind"

    Thiele Fig 5.

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    Unpaginated      |      Vol_IX-0187                                                                                                                  

    Midship Section U.S.C.G.C. "East Wind"

    Fig. 6

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