[1][9] While initially the idea of ordering two similar but technically different series of ships for the same purpose was to gain operational experience for the future arctic freighters,[8] shortly after the deal was made public the shipyards approached Sudoimport to agree on a uniform design.

Not only was running two parallel development projects wasting effort and resources for the shipyards, but constructing a single type of ships instead of two would bring savings to the customer in form of reduced maintenance and spare part costs.

[9] The first ship of the class, Norilsk from Wärtsilä, was delivered on 13 November 1982 from the Perno shipyard in Turku, half a year behind schedule due to the prototype nature in many of its systems.

[13] Minor modifications were made to the design based on the operator's experiences during the exceptionally hard arctic winter,[14] resulting in a subclass sometimes referred to as SA-15 Super.

In winter the SA-15 type freighters mainly supported the Norilsk-Dudinka operation, providing a continuous flow of non-ferrous metal concentrates to the smelters of the Kola Peninsula and other industries within the Soviet Union,[23] but also carried other cargo especially when the ice conditions became too difficult for other vessels.

In 2009, Igarka was used as a setting for the opening scene of the 2010 action movie The Expendables while the ship was staying at Rio de Janeiro, Brazil, for repair work.

The ships, no longer required to sail in the arctic conditions, were renamed Speybank, Arunbank, Foylebank and Teignbank and converted in the United Kingdom for the South Pacific service.

The ships, while still managed by Bank Line, were time chartered, renamed to Mahinabank, Tikeibank, Gazellebank and Boularibank, and sent to Singapore for drydocking and extensive refits.

[27][28] However, due to the economic downturn of 2009 the round-the-world cargo liner service was discontinued, the charters were ended, and the four converted SA-15 type ships were returned to their original owner and sold for scrap in late 2009.

On 28 April 2009, on her last complete voyage in round-the-world service, Boularibank was attacked by Somalian pirates 120 miles northeast of Socotra Island at the entrance to the Gulf of Aden.

Unable to outrun the attackers, Captain Peter Stapleton carried out evasive manoeuvres while under fire from the assailants' AK-47s and RPGs and had his crew ward off the invaders using water cannons, twistlocks and heavy balks of timber lashed to the guard rails.

By the time a destroyer of the Russian Navy arrived at the scene the pirates had given up, leaving Boularibank's crew of 31, eleven passengers and the captain's wife unharmed.

[35] In early 2009 another SA-15 type ship, the Monchegorsk, became the centre of an international incident involving Iran, Egypt, Russia, the United States, Israel, the Palestinian territories and Cyprus.

On 11 July 2011, more than two years later, the confiscated containers, stored in the open under allegedly inappropriate conditions at the Evangelos Florakis Naval Base near Mari, exploded, leaving 12 people dead and 62 injured.

[23] In November 2010 one of these new vessels capable of breaking ice up to 1.7 metres (5.6 ft) thick when operating astern,[40] Monchegorsk, became the first ship to traverse the eastern part of Northern Sea Route without icebreaker assistance while sailing from Murmansk via Dudinka to Shanghai.

[42] It was followed by the four ships operated by Bank Line – Boularibank was sold for recycling in India and Gazellebank, Tikeibank and Mahinabank in Bangladesh during the second half of 2009 – and Monchegorsk, which arrived at the breakers in China in late 2009.

[5] The shallow waters of the Northern Sea Route limit the draught to 9 metres (29 ft 6 in), but outside the arctic their cargo capacity can be increased by allowing the ice-strengthened parts of the hull to become submerged.

[55] For this reason the hull form of the SA-15 type freighters resembles that of icebreakers and their robust propulsion system has several innovative features and prototype arrangements to improve the ships' operational capability.

A special high-strength steel, Rautaruukki Raex E32 Polar, is used in the main components of the ice zone where it was protected by abrasion-resistant low-friction paint, Inerta 160.

[1] Propulsion power is provided by two 14-cylinder Wärtsilä-Sulzer 14ZV40/48 4-stroke medium-speed diesel engines running on heavy fuel oil, each with a maximum continuous output of 7,700 kW (10,326 hp) at 560 rpm.

[5] The main engines are connected to a single propeller shaft through a double input/single output single-stage reduction gear manufactured in Finland by Valmet Rautpohja Works in co-operation with Renk AG.

[56][59] The shaft line is designed according to a certain hierarchy of strength, meaning that if the maximum load is exceeded, yielding occurs in predefined points before components that are more expensive or difficult to repair are damaged.

[1] The propeller hubs, which house the pitch adjusting mechanism dimensioned for arctic ice conditions, have a diameter of 2.35 metres (7.7 ft) and were, at the time of the building, the largest ever constructed.

1, is specially designed for the carriage of explosives for the mining industry, inflammable liquids and chemicals in packages, and for this reason has a separate seawater fire extinguishing system that can also be used to cool the bulkhead between the foremost holds.

These hovercraft, manufactured by Wärtsilä, were powered by a 625 kW stern-mounted diesel engine driving two fans giving the platform a hovering height of 0.6–0.7 m (2.0–2.3 ft).

They were capable of carrying a payload of 38 tonnes over ice, water, land and marshy terrain when towed by a tractor or a tug or, if necessary, by using an auxiliary propulsion unit that gave the platform a speed of at least two knots.

The cargo-carrying capacity of the ships was increased by converting deep tanks between the cargo holds and below the lower deck in the bow for the carriage of vegetable oils.

Other changes included upgrading the cargo handling and lifesaving equipment, converting ten cabins for passengers and installing a new incinerator to deal with the shipboard waste.

[63] When China Navigation Co Ltd bought the South Pacific service from Andrew Weir Shipping in 2006, the four SA-15 type freighters were time chartered by the new owner and further modified during drydocking in Singapore.

Fuel efficiency was further improved by grit blasting the underwater parts to minimize hull roughness and installing wake-equalising ducts and a rudder bulb.