Keel or Will? (2)
Part of the success of Roald Amundsen’s explorations is certainly to be attributed to his ability to always have ready all the necessary equipment for the expedition. Particularly important were his contributions for the design of the hull and the material to be used for vessels destined to sail Polar seas, which all prove that his discoveries were not only geographic.
The experience on board the Belgian RV, the vessel used for the first winter expedition to the Antarctic, was definitely illuminating with regard to the shape and materials used for the keel, which were the most suitable to navigate through ice.
Indeed, when the vessel and the crew were trapped in the ice for a whole year, Belgica was dismantled to be made into a shelter for protection from freezing and then reassembled with a more rounded keel to set off again in March 1899.
However, it was perhaps Fram, on which Amundsen reached the Antarctic and then on to the South Pole, the wooden hulled boat that best represents the innovation of naval engineering in the design of vessels, able to navigate Polar waters. The approach to design was not intended to emphasize the struggle against nature and the typically British sense of sacrifice, but the Scandinavians put their trust in the explorers’ competence and their ability to adapt to the environment. Construction commenced in 1891 in Colin Archer’s shipyard in Larvik.
The two elements that made up the keel were the use of American Elm, while the fuselage was in Pitchpine. All of the bulkhead frame was made of the highest quality of Norwegian Oak. The prow was constructed from three pieces of exceptionally strong oak estimated at 1.25 m thick. The double oak plating reached a thickness of 17 cm. From the keel to the float line, the spaces between the frames were filled with a mixture of tar and sawdust. To this was added a thermic insulating lining made of cork, sawdust and reindeer skin to a total bulwark thickness of 80 cm. Externally, the prow and stern were protected in a metal casing. Furthermore, the architect designed what he called ” an ice jacket”, a supplementary covering of 10 cm Greenheart on the float line 7 cm from the keel and hooked on to the first plating . The ship was launched on 26th October 1892.
This was an exemplary feat of advanced construction for the time, which has remained fundamentally unchanged today. Although steel plating has replaced wood, being the most suitable material to construct highly resistant vessels, the so-called “multi- system structure” is derived from Fram’s engineering.
This is a compromise between the Transversal and Longitudinal systems: in other words, the strength of the hull lies prevalently in the longitudinal structure (on the bottom and the bridges), while at the prow, stern and sides the transversal system is used.
An example of state-of-the-art shipbuilding when the most extreme sea conditions have to be faced during navigations, it can now be admired in our shipyards, which are involved in the realisation of a luxury steel 38 Explorer. We are proudly showing some photographs for reference.