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74 THE MarRINE REVIEW DANISH SUBMERSIBLE DyYKKEREN. ranges from 800 to 1,500 metres and while running at different speeds sub- merged, A little later, the boat had a six-hour under-water run, during which she maintained a uniform depth of four metres, and 'held this depth except during momentary inattention on the part of the man at the diving rudder, and then altered depth about a metre anda' half. Three different men controlled in turn the submerging | rudders--each. officiating in half-hour periods." ; ne During the past. year, the Italian government sent its submersibles out for Special maneuvers. They. were kept at sea for a period of more than a month--having no touch with the land during that time, and their mo- bile operative base was the mother- ship, Lombardia. None of these ves- sels had a greater displacement than that of 214 tons submerged, and this sea-keeping performance is both signi- ficant and exceptionally creditable. The accompanying picture of the Dykkeren just before launching gives a good idea -of- the form of hull peculiar to the Laurenti boats. To submerge, the superstructure ports are opened, and the space fills freely with water as the craft trims deeper owing to the admission of water into her bottom ballast tanks. When the boat comes to the surface after a submerged run, the superstructure frees itself automatically, and no pumps or other mechanical means are required to handle this mass of water. This is. a prime military advantage; because it makes it possible to give the vessel a surface factor of safety of great buoyancy, and yet does sot retard hasty submergence upon. the approach of a foe. The Italian govern- ment has given further evidence of approval by ordering eight more Lau- renti submersibles. The new. boats will have a submerged displacernent of nearly 300 tons and will be pro- pelled on the surface by means of heavy-oil engines. THE RecorpD-MAKING CRUISE OF THE February, 1919 SHIP BUILDING IN THE UNITE) KINGDOM. The ship building returns for last year show that exclusive of war ships 526 vessels of 991,068 tons gross were launched in the United Kingdom, while the war ships launched at both government and private yards num. bered 42 of 126,230 tons displacement. The total output for the United King- dom was 568 vessels, of 1,117,296 tons. The mercantile tonnage showed an in- crease of 61,397 tons 'but is the low- est total for 12 years, with the excep- tion of 1908. British colonies were the 'best customers for the ships, or- dering 70. vessels of 60,072 tons or' 6 per cent of the total output. . A comparison of the output in the 'United Kingdom and abroad, shows that a considerable decrease as com- pared with the 1908 figures is record- ed in the case of nearly every country, and is especially noticeable in France (over 49 per cent), Germany (nearly 40 per cent), and the United States (over 31 per cent). On tthe other hand, the tonnage launched in the United Kingdom shows an advance of 61,397 tons (or 6.6 per cent), 'on the output for 1908. Roy M. Wolvin has. resigned as manager of the Wolvin lines to de- vote his attention to the package freight trade in which he is interested. HVALEN FROM SPEZIA To STOCKHOLM.