Preservation of the hulls

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From outset the commission was worried about the problem of the preservation of the wood that the fine mud of the lake had miraculously protected. Earlier attempts at recovering objects from the lake showed that even the use of planks and beams could be used to display items with perfect preservation provided that they were placed in a suitable environment, protected from bad weather and humidity, without any special treatment. This, however suitable it may have been for small objects, was not however, a viable option for something as big as the ships.
It was, nevertheless, attempted to protect the wood from the deleterious action of the sun's rays and in his account, Cultrera records that on the advice of the commission, the hull was covered with protective cloths which were continuously wetted with pumps, as soon as timbers emerged from the lake, in order to avoid damage through too rapid drying out.
Once freed from the mud both internally and at its sides, in June 1930 the prima nave was covered by a hanger of cloth, supplied by the Air Force and which, after towing up the slipway onto solid ground, was re-erected in February 1931.
Despite every precaution the drying out of the wood even through the sole action of the air, was too fast for the uncovered parts which dried out faster than the internal sections or other areas protected by other structures or coverings. This produced notable damage to the surface layers that promptly warped cracked and flaked, starting a disintegration of the hulls which had been recovered virtually intact. The conditions pertaining to the second hull were even more difficult to cope with. Leaving aside the fact that the state of the second hull was notably worse than the first for reasons which cannot be stated, the re-immersion of the hull after having partially dried out had further deleterious consequences for the state of the hull, notwithstanding the measures which were implemented as a result of experience with the first.
Since 1930 the commission had taken care to gather information on various methods of preserving wood, among these the Oslo Museum for the preservation of the Viking longships.The preservation of the Norwegegian vessels had been ensured through use of a vegetable tar diluted in solvents and applied to various areas sometimes up to ten times. For greater success in the operation, given the large size of the vessels, the members were often removed and then after treatment put back into the original position.

The recovery of the original volume of the wooden members was obtained through steam, preceded in the case of wood already dried out, by a bath of water and formalin.
In a meeting at the lakeside on 21 July 1931 the commission decided to adopt the treatment as had been used by the Oslo Museum. (Photo shows the application of tar to the seconda nave - the difference in colour between the treated and untreated parts can be seen)
Admiral Sirianni supplied the first tons of vegetable tar and the work of applying it to the wood was started immediately. As previously noted, the landslip of August 22 cause the draining of the lake to be suspended and slowly the hull of the ship was once again submerged. It was only the following spring that once again the pumps could start again and the hull was brought definitively out of the water. This done, on 13 October 1932 while the second ship was being dragged up clear of the lake, a meeting was held to discuss once again which method of preservation to use. The outcome was a decision to repeat the treatment of vegetable tar with partial use of hot application for certain areas. The most pressing problem by this point was getting the ship under proper cover out of the ravages of sun and rain, much more so since the seconda nave showed signs of attack by parasites.

In the meantime, a temporary protection was made for it from an immense sheathing of wood, tarred cardboard and cloth (see photo).
After the storm of 5 February 1934 that tore off the covering from the hangar protecting the prima nave, the same sort of protection was rigged up for it too.