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Defining ice-strengthening requirements, the Swedish Maritime Administration uses the Finnish-Swedish Ice-Class Designations valid from 2009. The maximum ice-class draught amidships shall normally be taken as the summertime fresh-water load line draught according to Finnish-Swedish Ice-Classes TSFS 2009:111.

The Finnish Transport Agency(FTA) and the Swedish Maritime Administration (SMA) have developed the Finnish – Swedish ice class rules in co-operation with classification societies. The first version of Guidelines for the Application of Finnish-Swedish Ice Class Rules was puplished 20 December 2005. These guidelines will be updated and complemented as the development of rules continues.

For vessels that according to provisions in TSFS 2009/111 (Finnish-Swedish ice class) are existing vessels and holds ice class IA Super and IA, the older provisions concerning machine effect apply until January 1, 2005 or January 1 the year when 20 years have passed since the vessel was delivered, depending on which falls last.

The vessel's engine power is considered to be the total propulsion machinery power for which the vessel and machinery are designed. If technical means are used to prevent the machinery from being driven with full power, or if this is prohibited according to regulations being followed on board, then the power limited in this manner is considered to be the vessel's engine power.

Finnish-Swedish Ice-Class Designations

Ice Class For navigation in Metres
IA Super extremely difficult ice-conditions   > 1,0 m
IA difficult ice-conditions  > 0,5-1,0 m
IB moderately difficult ice-conditions  0,3-0,5 m
IC easy ice-conditions  0,15-0,3 m
II very easy ice-conditions  0,1-0,15 m

Requirements for ice class and tonnage size

For shipments to Norrland the following are the dates on which restrictions for traffic at sea normally come into force:

At least class/least dwt The Bay of Bothnia The Bothnian Sea
II / 2 000 1/12 1/1
IC / 2 000 15/12 15/1
IB / 2 000 1/1 1/2
IA / 3 000 15/1 15/2
IA / 4 000 31/1 -
IA / 3 000 10/4 -
IB / 2 000 10/5 1/4
II / 2 000 15/5 15/4


The dates given here are guides for the sea areas in question. During severe ice conditions assistance can be given only after special permission.

The Swedish Maritime Administration will, if possible, announce changes in the restrictions for traffic at sea 6 days before these changes come into force. When the Swedish Maritime Administration decides about reduction or cancellation of restrictions, the decision comes into force the same day it is announced.

For shipments in other coastal areas corresponding guiding dates cannot be given because of the variations in the ice obstacles which occur. In Lake Vänern and Lake Mälaren restrictions must normally be expected during January-April.

The ice class and tonnage requirements vary depending on the severity of the winter season. Small ports and loading places, in particular, must be closed in such cases if they have no ice-berakers of their own available and if the availability of state ice-breakers is limited.

Small ports and loading places must expect to be closed even if shipping occurs in the rest of the area.

Local ice-breakers of sufficient size and with sufficient engine power must be provided within the various districts. Local ice-berakers cannot normally expect assistance from one district to another or within the district.

The traffic restrictions may be combined with loading restrictions on, for example, 2,000 tonnes loaded and/or unloaded goods per port.