Section 1 Strengthening requirements for navigation in ice – Application of requirements

1.1.1 Where additional strengthening is fitted in accordance with the requirements given in this Chapter, an appropriate special features notation will be assigned. It is the responsibility of the Owner to determine which notation is most suitable for his requirements.

1.1.2 Where a special features notation is desired, the ship is to comply with the requirements of the applicable Sections, in addition to those for sea-going service, so far as they are applicable.

1.1.3 Where the hull and machinery are constructed so as to comply with the requirements of different ice classes, then the assigned Ice Class Notation will be indicated for the combination as the lower of these classes on the Certificate of Class. Any compliance of the hull or machinery with the requirements of a higher ice class will be indicated in square brackets after the main notation. Other supplementary information that would influence the ice performance will also be indicated. For example, a ship hull built in compliance with 1B FS and the machinery in compliance with 1AS FS would be assigned the Notation Ice Class 1B FS [1AS FS Machinery] or Ice Class 1B FS [1AS FS azimuth thrusters] where azimuth thrusters are included in the approval.

1.1.4  The vertical extent of the ice strengthening is related to the upper ice waterline and lower ice waterline, which are defined in Pt 8, Ch 2, 2.2 Definitions. The maximum and minimum draughts at the fore, amidships and aft ends (for the lowest ice class) are to be stated on the Certificate of Class.

1.1.5 For ships that comply with the requirements of the Finnish-Swedish Ice Class Rules, the installed and required minimum engine output (for the lowest ice class), see Pt 8, Ch 2, 7 Machinery requirements for first-year ice conditions – Ice Classes 1AS FS(+), IAS FS, 1A FS, 1A FS(+), 1B FS, 1B FS(+), 1C FS(+) and 1C FS, will be stated on the Certificate of Class.

1.2.1 The requirements for Ice Class IE are for ships with length less than 150 m and are intended to navigate in very light first-year ice conditions, such as in brash ice and small ice pieces. The requirements of Pt 8, Ch 2, 4 Hull requirements for light ice conditions – Ice Classes 1D and 1E and Pt 8, Ch 2, 5 Machinery requirements for light ice conditions – Ice Classes 1D and 1E are to be complied with.

1.2.2 The requirements for Ice Class 1D are for ships intended to navigate in light first-year ice conditions. The requirements for strengthening the forward region, the rudder and steering arrangements for Ice Class 1C FS are applicable.

1.3.1 Ships that comply with the requirements of the Finnish Swedish Ice Class Rules and Pt 8, Ch 2, 6 Hull requirements for first-year ice conditions – Ice Classes 1AS FS, 1A FS, 1B FS, 1C FS and 1D and Pt 8, Ch 2, 7 Machinery requirements for first-year ice conditions – Ice Classes 1AS FS(+), IAS FS, 1A FS, 1A FS(+), 1B FS, 1B FS(+), 1C FS(+) and 1C FS, for Ice Class IA Super, IA, IB and IC may be assigned the corresponding notations Ice Class 1AS FS, Ice Class 1A FS, Ice Class 1B FS or Ice Class 1C FS. The Finnish-Swedish Ice Class Rules may be obtained from the following website:

www.trafi.fi

1.3.2 For ships where the ice class notation Ice Class 1AS FS(+), Ice Class 1A FS(+), Ice Class 1B FS(+) or Ice Class 1C FS(+) is requested, the requirements of the Finnish-Swedish Ice Class Rules, and Sections 8 and 9 are to be complied with.

1.4.1 The requirements for strengthening for navigation in ice, as given in Pt 8, Ch 2, 10 Hull strengthening requirements for navigation in multi-year ice conditions – Ice Classes PC1, PC2, PC3, PC4, PC5, PC6, PC7 and Icebreaker and Pt 8, Ch 2, 11 Machinery strengthening requirements for navigation in multi-year ice conditions – Ice Classes PC1, PC2, PC3, PC4, PC5, PC6, PC7 and Icebreaker, are intended for ships operating in multi-year ice in Arctic or Antarctic ice conditions under their own power and constructed of steel.

1.4.2 For ships assigned a Polar Class (PC) notation, the hull form and propulsion power are to be such that the ship can operate independently and at a continuous speed in a representative ice condition, as defined in Table 2.1.1 Polar class descriptions for the corresponding Polar Class. For ships and ship-shaped units which are intentionally not designed to operate independently in ice, such operational intent or limitations will be explicitly stated on the Certificate of Class.

1.4.3  For ships of polar classes PC1, PC2, PC3, PC4 and PC5, bows are to be of icebreaking form with bow angles generally within the range specified in Pt 8, Ch 2, 10.3 Design ice loads – General 10.3.5. Other bow forms are to be specially considered, see Pt 8, Ch 2, 10.3 Design ice loads – General 10.3.9. Bows with vertical sides and bulbous bows are generally to be avoided.

1.4.4 For ships of polar classes PC6 and PC7 that are designed with a bow with vertical sides or with a bulbous bow, operational limitations (restricted from intentional ramming) in the design conditions are to be stated on the Certificate of Class.

1.4.5 Ships that comply with Pt 8, Ch 2, 10 Hull strengthening requirements for navigation in multi-year ice conditions – Ice Classes PC1, PC2, PC3, PC4, PC5, PC6, PC7 and Icebreaker and Pt 8, Ch 2, 11 Machinery strengthening requirements for navigation in multi-year ice conditions – Ice Classes PC1, PC2, PC3, PC4, PC5, PC6, PC7 and Icebreaker can be considered for a Polar Class (PC) notation as listed in Table 2.1.1 Polar class descriptions.

1.4.6 The Polar Class (PC) notations and descriptions are given in Table 2.1.1 Polar class descriptions. It is the responsibility of the Owner to select an appropriate Polar Class. The descriptions in Table 2.1.1 Polar class descriptions are intended to guide owners, designers and administrations in selecting an appropriate Polar Class to match the requirements for the ship with its intended voyage or service.

1.4.7 The Polar Class notation is used throughout Pt 8, Ch 2, 10 Hull strengthening requirements for navigation in multi-year ice conditions – Ice Classes PC1, PC2, PC3, PC4, PC5, PC6, PC7 and Icebreaker and Pt 8, Ch 2, 11 Machinery strengthening requirements for navigation in multi-year ice conditions – Ice Classes PC1, PC2, PC3, PC4, PC5, PC6, PC7 and Icebreaker to convey the differences between classes with respect to operational capability and strength.

1.5.1 Sea-going ships specially designed for ice-breaking duties will be assigned the ship type notation 'Icebreaker' in addition to the special features notation appropriate to the degree of ice strengthening provided. 'Icebreaker' refers to any ship having an operational profile that includes escort or ice management functions, having powering and dimensions that allow it to undertake aggressive operations in ice-covered waters, and having a class certificate endorsed with this notation. The additional ship type notations may be assigned as follows:

1.6.1 Sufficient information is to be supplied to the Master of every ship to enable him to arrange loading and ballasting in such a way as to avoid the creation of unacceptable stresses in the ship’s structure. The following information is to be included in the vessel’s loading manual:

1. Upper and lower ice waterline.

2. Propeller immersion.

3. Indication of whether the vessel is strengthened for icebreaker towing.