Commuter Ferry Skarven

The archipelago of the province of Aland comprises approximately 6,500 islands. There are 9 archipelago municipalities with a combined population of around 2,200 people. In addition to the castles and numerous bridges, there are 10 passenger car ferries in the archipelago, which enable the islands to be connected to the main island and the Finnish mainland with ships that can transport vehicles to the islands, the size of which is limited by the same rules as on the mainland. This makes it possible to live on the islands all year round, practice agriculture, fishing and industrial activities, and be sure that the products can be delivered to customers reliably in all seasons.

The three newest of the Aland archipelago’s ferry ships were built according to our concept and basic design, the previous five were built and designed by Laivateollisuus Oy. In all the ships, the main principle of the design has been a ship that moves well in ice, with good open water features, whose car deck can accommodate large trucks or several cars, and where passengers have their own salon and cafe. The travel time of each ship is different, it varies from half an hour to three hours. On the way, they stop at several islands that are inhabited all year round.

The newest ship, Skarven, differs from previous ships in that due to its short travel route, it has been made “double headed”, meaning it has the same bow and stern, so the ship does not have to be turned when it travels between ports. Travel time and energy are not spent turning the ship. The ship is designed for traffic between the main island of Aland and Föglö, where the one-way journey time is about half an hour.

The ship’s design also differs from its predecessors in that its ice reinforcements are “only” in accordance with ice class 1A, while the predecessors have been stronger, partly with 1A Super ice reinforcements. In terms of ice conditions, Föglö is easier in the southern region of Aland than the ferry traffic areas of the northern region, so the provincial government of Aland wanted to make the vessel lighter and use less energy in open water use than its predecessor. However, the ship’s ice-passing properties and ice reinforcements had to be sufficient, and Skarven was designed according to “archipelago dimensions” in such a way that the bottom ice reinforcements were added to the minimum.

Archipelago design interested the ship’s classification society Lloyds Register of Shipping to such an extent that they proposed a Joint Industry Project (JIP), a study on ice properties, reinforcements and propulsion. After negotiations, the ship’s owner Aland County Government, its classifier Lloyds Register of Shipping (London), designer ILS Oy (Turku), propeller equipment supplier Rolls Royce Oy (Rauma) and construction yard Western Shipyard (Klaipeda) participated in the product development program. The research program included the study of plans and calculation methods as well as extensive measurements of the conditions (ice thicknesses, temperatures, winds, etc.), hull strengths and propeller devices and their support structures lasting about a week. The measuring sensors were installed on the ship during construction at mutually agreed locations in the fall of 2009, and the measurements were carried out after the ship’s completion in February 2010. The ice tests also examined the operation of the machine’s box-cooler cooling system, and it was concluded that the system works flawlessly even in slushy ice fields, where even the ice bottom wells could easily become blocked.

Skarven was completed at the shipyard in October 2009 and began traffic in November 2009.