6.3 Fishing vessels

 For vessels operating in areas where ice accretion is likely to occur, the following icing allowance should be made in the stability calculations:

• .1 30 kg per square metre on exposed weather decks and gangways;

• .2 7.5 kg per square metre for projected lateral area of each side of the vessel above the water plane;

• .3 the projected lateral area of discontinuous surfaces of rail, sundry booms, spars (except masts) and rigging of vessels having no sails and the projected lateral area of other small objects should be computed by increasing the total projected area of continuous surfaces by 5% and the static moments of this area by 10%.

 Vessels intended for operation in areas where ice is known to occur should be:

• .4 designed to minimize the accretion of ice; and

• .5 equipped with such means for removing ice as the Administration may require; for example, electrical and pneumatic devices, and/or special tools such as axes or wooden clubs for removing ice from bulwarks, rails and erections.

 In the application of the above standards, the following icing areas should apply:

• .1 the area north of latitude 65° 30΄ N, between longitude 28° W and the west coast of Iceland; north of the north coast of Iceland; north of the rhumb line running from latitude 66° N, longitude 15° W to latitude 73° 30΄ N, longitude 15° E, north of latitude 73° 30΄ N between longitude 15° E and 35° E, and east of longitude 35° E, as well as north of latitude 56° N in the Baltic Sea;

• .2 the area north of latitude 43° N bounded in the west by the North American coast and the east by the rhumb line running from latitude 43° N, longitude 48° W to latitude 63° N, longitude 28° W and thence along longitude 28° W;

• .3 all sea areas north of the North American Continent, west of the areas defined in 6.3.2.1 and 6.3.2.2;

• .4 the Bering and Okhotsk Seas and the Tartary Strait during the icing season; and

• .5 south of latitude 60° S.

 A chart to illustrate the areas is attached at the end of this chapter.

 For vessels operating in areas where ice accretion may be expected:

• .6 within the areas defined in 6.3.2.1, 6.3.2.3, 6.3.2.4 and 6.3.2.5 known to having icing conditions significantly different from those described in 6.3.1, ice accretion requirements of one half to twice the required allowance may be applied; and

• .7 within the area defined in 6.3.2.2, where ice accretion in excess of twice the allowance required by 6.3.1 may be expected, more severe requirements than those given in 6.3.1 may be applied.

  6.3.3.1 The skipper of a fishing vessel should bear in mind that ice formation is a complicated process which depends upon meteorological conditions, condition of loading and behaviour of the vessel in stormy weather as well as on the size and location of superstructures and rigging. The most common cause of ice formation is the deposit of water droplets on the vessel's structure. These droplets come from spray driven from wave crests and from ship-generated spray.

  6.3.3.2 Ice formation may also occur in conditions of snowfall, sea fog (including arctic sea smoke), a drastic fall in ambient temperature, as well as from the freezing of drops of rain on impact with the vessel's structure.

  6.3.3.3 Ice formation may sometimes be caused or accentuated by water shipped on board and retained on deck.

  6.3.3.4 Intensive ice formation generally occurs on stem, bulwark and bulwark rail, front walls of superstructures and deck-houses, hawse holes, anchors, deck gear, forecastle deck and upper deck, freeing ports, aerials, stays, shrouds, masts and spars.

  6.3.3.5 It should be borne in mind that the most dangerous areas as far as ice formation is concerned are the sub-Arctic regions.

  6.3.3.6 The most intensive ice formation takes place when wind and sea come from ahead. In beam and quartering winds, ice accumulates quicker on the windward side of the vessel, thus leading to a constant list which is extremely dangerous.

  6.3.3.7 Listed below are meteorological conditions causing the most common type of ice formation due to spraying of a vessel. Examples of the weight of ice formation on a typical fishing vessel of displacement in the range 100 t to 500 t are also given. For larger vessels the weight will be correspondingly greater.

  6.3.3.8 Slow accumulations of ice take place:

• .1 at ambient temperature from -1°C to -3°C and any wind force;

• .2 at ambient temperature -4°C and lower and wind force from 0 m/s to 9 m/s; and

• .3 under the conditions of precipitation, fog or sea mist followed by a drastic fall of the ambient temperature.

 Under all these conditions the intensity of ice accumulation may not exceed 1.5 t/h.

  6.3.3.9 At ambient temperature of -4°C to -8°C and wind force 10 m/s to 15 m/s, rapid accumulation of ice takes place. Under these conditions the intensity of ice accumulation can lie within the range 1.5 t/h to 4 t/h.

  6.3.3.10 Very fast accumulation of ice takes place:

• .1 at ambient temperature of -4°C and lower and wind forces of 16 m/s and over; and

• .2 at ambient temperature -9°C and lower and wind force 10 m/s to 15 m/s.

 Under these conditions the intensity of ice accumulation can exceed 4 t/h.

  6.3.3.11 The skipper should bear in mind that ice formation adversely affects the seaworthiness of the vessel as ice formation leads to:

• .1 an increase in the weight of the vessel due to accumulation of ice on the vessel's surfaces which causes the reduction of freeboard and buoyancy;

• .2 a rise of the vessel's centre of gravity due to the high location of ice on the vessel's structures with corresponding reduction in the level of stability;

• .3 an increase of windage area due to ice formation on the upper parts of the vessel and hence an increase in the heeling moment due to the action of the wind;

• .4 a change of trim due to uneven distribution of ice along the vessel's length;

• .5 the development of a constant list due to uneven distribution of ice across the breadth of the vessel; and

• .6 impairment of the manoeuvrability and reduction of the speed of the vessel.

  6.3.4 Operational procedures related to ensuring a fishing vessel's endurance in conditions of ice formation are given in annex 2 (Recommendations for skippers of fishing vessels on ensuring a vessel's endurance in conditions of ice formation).