• 1. (1) Subject to subsections (2), (3) and (7), the minimum continuous shaft power in kilowatts available from the propulsion machinery of every Arctic class ship shall not be less than the numerical value obtained from

  • (a) P_r × D_r ÷ D if D_r ÷ D ≥ 1, or

  • (b) P_r if D_r ÷ D ≤ 1,

    where

  • (c) “Pr” = (579.4-2.6 W^1/3) BA²,

  • (d) “B” = the maximum breadth of the ship at the operating waterline in metres,

  • (e) “W” = displacement of the ship in tonnes at the operating waterline,

  • (f) “Dr” = 0.05 √ Pr ÷ Z ,

  • (g) “D” = the diameter of the propellers in metres except that where the propellers are of different diameters,

    • D = √ (D₁² + D₂² + D₃²) ÷ Z ...,

  • (h) “Z” = the number of propellers, and

  • (i) “A” = for an Arctic Class ship set out in Column I of an item of the table to this section, the value shown in Column II of that item.

  	Column I	Column II
  Item	Arctic Class	Value of A in metres
  1	1	0.305
  2	1A	0.458
  3	2	0.610
  4	3	0.915
  5	4	1.220
  6	6	1.830
  7	7	2.135
  8	8	2.440
  9	10	3.050

• (2) The minimum continuous shaft power available for the propulsion of every Arctic class ship shall not be less than that required to propel the ship in still water at a speed of 12 knots.

• (3) A pollution prevention officer may accept a ship as an Arctic class ship where the shaft power is less than that required by subsection (1) for a ship of that Arctic class if the owner of the ship has demonstrated by physical model tests or by actual demonstration that the ship is suitable for navigation in those zones and at those times of year in which a ship of that Arctic class is permitted to operate.

• (4) The shaft power that the propelling machinery of every Arctic class ship is able to develop when going astern shall not be less than 70 per cent of the power required for that ship in subsection (1) and the machinery shall be able to maintain that power for a period of not less than three hours.

• (5) Every ship of Arctic class 10, 8 or 7 shall be

  • (a) powered by not less than two prime movers; and

  • (b) provided with not less than two propellers, each located at the stern.

• (6) Every Arctic class ship that is propelled by steam driven machinery shall be provided with not less than two boilers that have an equal maximum evaporation rate.

• (7) Every Arctic class ship that is propelled by diesel machinery other than

  • (a) diesel electric machinery, or

  • (b) diesel machinery that drives a controllable pitch propeller,

  shall be provided with machinery capable of developing 1.1 times the shaft power derived from the formula in subsection (1).

• 2. (1) The propulsion machinery, gearing, shafting and propellers of every Arctic class 3, 4, 6, 7, 8 and 10 ship shall be designed so as to take into account the conditions that arise in the propulsion system when the propeller could be slowed or jammed by ice.

• (2) Means shall be provided to prevent the prime movers of every Arctic class ship from overspeeding.

• (3) Where an electric motor is used for the propulsion of any Arctic class ship, provision shall be made to automatically protect the motor from

  • (a) excess torque;

  • (b) overloading; and

  • (c) overheating.

• 3. (1) The calculations made to determine the dimensions of a propeller and screw shaft of every Arctic class ship shall include an ice torque factor.

• (2) The ice torque factor described in subsection (1) shall be derived from the following formula

  M = mD²     kN.m

   where

  • (a) “D” = the propeller diameter in metres; and

  • (b) “m” = for an Arctic class ship set out in Column I of an item of the table to this section, the value shown in Column II of that item.

  	Column I	Column II
  Item	Arctic Class	Value of “m”
  1	1	12.0
  2	1A	15.7
  3	2	17.7
  4	3	21.1
  5	4	24.0
  6	6	28.5
  7	7	30.1
  8	8	32.2
  9	10	33.0

4. Materials used for propellers and shafting of every Arctic class ship shall be tested in accordance with

• (a) the Marine Machinery Regulations; or

• (b) in the case of a ship that is certificated by an exclusive surveyor of one of the classification societies described in paragraph 13(1)(b), the rules of that society.

• 5. (1) Propellers of every Arctic class ship shall be made of a material that has

  • (a) an elongation of not less than 19 per cent; and

  • (b) if made of carbon or low alloy steel, a Charpy V-notch test value of not less than 20.34 J at -10°C.

• (2) The width and thickness of propeller blade sections shall not be less than that determined by the following formulae:

  • (a) for solid propellers at 25 per cent of the radius measured from the centre of the boss

  WT² = 2648 ÷ (S ( 0.65 + 0.7P )) ( 272H ÷ RN + 20.39M ) cm³,

  • (b) for controllable pitch propellers at 35 per cent of the radius measured from the centre of the boss

  WT² = 2108 ÷ (S ( 0.65 + 0.7P )) ( 272H ÷ RN + 23.45M ) cm³,

  • (c) for all propellers at 60 per cent of the radius measured from the centre of the boss

  WT² = 932 ÷ (S ( 0.65 + 0.7P )) ( 272H ÷ RN + 28.55M ) cm³,

  where

  • (d) “W” = expanded width of a cylindrical section of the propeller blade at the appropriate radius in centimetres;

  • (e) “T” = maximum thickness of the propeller blade at the appropriate radius in centimetres;

  • (f) “P” = in the case of a fixed pitch propeller, the propeller pitch in metres at the appropriate radius divided by the propeller diameter, or in the case of a controllable pitch propeller, 0.7 times the nominal pitch in metres divided by the propeller diameter;

  • (g) “H” = the maximum shaft power in kilowatts available for that propeller;

  • (h) “S” = the ultimate tensile stress of the material of the propeller blade in megapascals;

  • (i) “M” = the ice torque as determined in accordance with section 3 of this Schedule;

  • (j) “R” = propeller revolutions per minute at the maximum shaft power available for that propeller; and

  • (k) “N” = number of blades.

• (3) The propeller blade thickness at 95 per cent of the radius measured from the centre of the boss shall not be less than that determined from the following formulae for a ship of the appropriate Arctic class:

  • (a) for an Arctic class 10, 8, 7, 6, 4, 3 or 2 ship

  t = ( 20 + 2D )  √ 490/S mm, and

  • (b) for an Arctic class 1A or 1 ship

  t = ( 15 + 2D )  √ 490/S mm,

   where

  • (c) “t” = thickness of blade in millimetres;

  • (d) “D” = diameter of propeller in metres; and

  • (e) “S” = ultimate tensile stress of the material of the propeller blade in megapascals.

• (4) The strength of the mechanism in the boss of a controllable pitch propeller shall be 1 1/2 times the strength of one of the blades when a load is applied at 9/10 of the radius from the centre of the boss in the weakest direction of the blade.

• 6. (1) Subject to subsection (2) and section 9 of this Schedule, the diameter of a screw shaft of every Arctic class ship shall not be less than that derived from the following formulae:

  • (a) if the diameter of the propeller boss is one-quarter of the diameter of the propeller or less,

    Screw Shaft Diameter

    

  • (b) if the diameter of the propeller boss is greater than one-quarter of the diameter of the propeller,

    Screw Shaft Diameter

    

     where

    • (c) “Su” = the ultimate tensile stress of the material of the propeller blade in megapascals;

    • (d) “Sy” = the yield stress of the material of the screw shaft in megapascals; and

    • (e) “WT²”, = in the case of the formula in paragraph (a) the value derived from the formulae in paragraph 5(2)(a) of this Schedule and in the case of the formula in paragraph (b) the value derived from the formulae in paragraph 5(2)(b) of this Schedule.

• (2) Where the diameter of a screw shaft when calculated by the appropriate formulae in subsection (1) is less than that of a screw shaft required by the appropriate formulae in the Marine Machinery Regulations, the diameter of the screw shaft shall not be less than that required by those Regulations.

• (3) When calculations are made to determine the diameter of the intermediate shaft in order to determine the diameter of the screw shaft for the purposes of subsection (2), the diameter of the intermediate shaft need not be increased as required in section 7 of this Schedule.

• (4) Where carbon or low alloy steel is used for the construction of a screw shaft, the material shall

  • (a) be subjected to a Charpy V-notch test at -10°C; and

  • (b) have an average energy value of not less than 20.34 j.

• 7. (1) Subject to subsection (2) and section 9 of this Schedule, the diameter of the intermediate and thrust shafts for an Arctic class ship set out in Column I of an item of the table to this section, shall be determined by the appropriate formula in the Marine Machinery Regulations, and the diameter determined by that formula shall be increased by the amount shown in Column II of that item.

  	Column I	Column II
  Item	Arctic Class	Percentage of Increase in Diameter
  1	1	No Increase
  2	1A	4
  3	2	8
  4	3	12
  5	4	15
  6	6 and 7	20
  7	8 and 10	20

• (2) Notwithstanding the requirements of subsection (1), the diameter of the intermediate and thrust shafts need not exceed 0.85 times the diameter of the screw shaft determined by section 6 of this Schedule.

• 8. (1) Subject to section 9 of this Schedule, where gearing is fitted between the engine and the propeller shafting of an Arctic class ship set out in Column I of an item of the table to this section, the gearing shall be designed and constructed to transmit, in addition to the maximum torque that the engine is able to develop, the percentage increase in torque that is set out in Column II of that item.

  	Column I	Column II
  Item	Arctic Class	Percentage of Increase in Torque
  1	1	15
  2	1A	15
  3	2	30
  4	3	50
  5	4	60
  6	6 and 7	70
  7	8 and 10	100

9. Notwithstanding the requirements of sections 5 to 8 of this Schedule, where, in the case of an Arctic class ship set out in Column I of an item of the table to this section, the propeller tips at their highest point are not less than the distance set out in Column II of that item below the lightest operating waterline of the ship, the construction of the propellers, shafts and gears need not be stronger than that required for an Arctic class 3 ship.

• 10. (1) Every Arctic class ship shall be provided with at least one sea bay or tank from which cooling water for machinery that is essential for the propulsion of the ship may be drawn.

• (2) The sea bays or tanks described in subsection (1) shall be

  • (a) located as close to the keel as practicable; and

  • (b) be supplied with water from more than one sea inlet box.

• (3) The sea inlet boxes described in paragraph (2)(b) shall

  • (a) be fitted on each side of the ship;

  • (b) each have an area open to the sea of at least six times the total area of the pump suctions served by the sea bay; and

  • (c) be connected to the sea by pipes, valves and a strainer so that the strainer may be shut off from the sea and from the sea bay and the cross sectional area of such pipes, valves and strainer shall be not less than the total area of the pump suctions served by the sea bay.

• 11. (1) Every sea water pump in an Arctic class ship that provides sea water to machinery essential for the propulsion of the ship shall be able to draw sea water directly from the sea bay or tank described in subsection 10(1) of this Schedule.

• (2) The design flow velocity of sea water through the suction pipe to any pump described in subsection (1) shall not be more than 2.03 m/s.

• (3) Cross connections shall be provided from the overboard discharge pipes from the machinery referred to in subsection (1) and such cross connections shall be

  • (a) connected to the pipe between the valve on the sea inlet box and the strainer;

  • (b) of the same bore as the overboard discharge pipe; and

  • (c) provided with a suitable system of valves so that the water may be re-circulated.

• 12. (1) Every Arctic class ship that is propelled with engines that are started by compressed air shall be provided with not less than two air receivers and the total capacity of the air receivers shall be sufficient to provide, without replenishment, air for

  • (a) 12 starts in the case of a ship with reversible engines; or

  • (b) six starts in the case of a ship with non-reversible engines.

• (2) The compressed air required in subsection (1) shall be provided by more than one independently driven air compressor and the air compressors shall have sufficient capacity to charge the air receivers from empty to maximum pressure in not more than 30 minutes.

• (3) The capacity of the smallest air compressor required by subsection (2) shall not be less than two-thirds of the capacity of the largest air compressor.