The Boat …

It All Began with the Vikings

The Koster is a Swedish type of small boat with a pointed stern, which was used as a fishing boat and pilot vessel and whose ancestors are the pointed Viking ships at the front and rear. This shape was presumably inevitable for the Viking ships because it was easiest to join the planks at the front and rear when building a plank boat.

Just like the traditional Danish fishing boat types with pointed sterns, which became the model for sports boat types, the coaster type was refined more and more over the course of a long constructional development. A high point, although perhaps not yet the conclusion of a long development from the Viking boat via the fishing and pilot boat to the elegant and seaworthy ocean-going yacht, is the Koster yacht “Casella” designed by the Swedish constructor Arvid Laurin, which achieved many successes in sea races and was also the smallest yacht to take part in the Bermuda-Skagen race, thus proving its suitability for long voyages across the Atlantic.

Laurin developed his L-cruiser from this successful design, which is only two centimeters longer than the “Casella”. It is certainly a point of naval architecture that such a venerable boat type as the Koster, with such a long line of ancestors, is now made of glass resin instead of the traditional and proven Scandinavian pine wood. And it is the first time that a yacht that has been tried and tested in Atlantic racing has been duplicated, so to speak, in large-scale production using plastic.

Stronger than Lloyds

However, the Swedish manufacturer has not contented itself with producing the Laurinkoster in the usual glass resin construction, but has instead used a sandwich construction. A damping spacer material made of PVC foam is enclosed between the outer and inner shells. The resulting strength is sufficient to dispense with the usual wooden or steel fuselage reinforcements. This eliminates the risk of uneven point loads, which could possibly lead to deformation of the plastic laminate.

The composition of the laminate complies with the regulations of the Royal Swedish Naval Administration, which are significantly stricter than those of Lloyds Register of Shipping. For example, Lloyds only requires a tensile breaking strength of 850 kp/cm², whereas the Swedish Naval Administration's regulations require 1050 kp/cm². The Malmö shipyard's experience in processing fiberglass-reinforced plastics for industrial purposes dates back to 1942.

A Classic Boat with Unconventional Hull Shape …

The Laurinkoster is certainly one of the most interesting boats to have appeared in our waters in recent years. The shape of the hull with its pronounced pointed stern differs considerably from our conventional ideas of a beautiful yacht. The overhangs are barely more than one meter. The non-slip deck is slightly convex towards the gunwale. This is known as a waldeck. It allows a favorable use of space in the cabin, but also has the disadvantage that the walkable area next to the superstructure is narrower than on a corresponding sea cruiser with a straight deck. The sea railing is fitted at the point where the rounded edge of the deck begins.

The yacht naturally has a watertight, self-draining cockpit. It contains two berths in the enclosed foredeck, behind which there is a toilet and washroom and closets, two sofa berths in the cabin and a dog berth on the starboard side behind the chart table, which extends into the forecastle. On the port side is the galley with a plastic sink, two-burner, gimballed stove and storage space for kitchen utensils; the cabin has full headroom and plenty of space. The entire interior fittings, floorboards, locker lids and all wooden parts on deck are made of teak.

… and Solid Rigging

All standing rigging, scaffolding, guard rails, bow and stern pulpit and rudder fittings are made of stainless steel. Rarely have such solid rigging irons been seen on a ship of these dimensions. The Laurinkoster spent hours hanging from a crane on each of the three shrouds. A test that speaks for itself. The mast and main boom can be supplied in either glass resin or aluminum. The glass resin spars are also a development of the Malmö shipyard and have been tested by various domestic and foreign institutes. The engine is a Penta-BB-30 for petroleum with an output of 25 to 40 hp or a Lombardini diesel of 20 hp. It is accessible from the companionway. The position lanterns and the other lighting points, such as the reading lamps above the bunks, are powered by the connected 12-volt unit.

Fast and Safe

The fact that the Laurinkoster is a fast ship is proven by her regatta successes to date. However, it is also a very stiff and safe touring yacht. The ballast accounts for almost 50% of the deadweight. The confidence placed in the designer Laurin in Scandinavia is demonstrated by the fact that 40 boats have already been purchased before the first boat in the series has even been launched. The Laurinkoster was developed in close contact with ten experienced ocean-going sailors from various countries.

This article about the Koster and the Laurinkoster appeared in the sixties in a German Sailing magazine and was typed out and republished by the German Gerd Holthausen on the website https://www.holthausen.de/laurin32/test.htm. Translated with DeepL.com, headings added by the webmaster.