Tehoretical investigations of typhoon surges along the Japanese coast (to be continued)

566

Oceanographic Abstracts

Les deux sexes arrivent en m6me temps ~ l'endroit de la ponte chez les e s p i e s qui s'accouplent pendant la migration, ce sont celles qui vivent en bancs. Chez les solitaires, un des sexes pr6c6de l'autre (ici, le m~le pr6c~de la femelle), l'accouplement a uniquement lieu ~ l'endroit del a ponte. Parmi les facteurs externes d6clenchant la migration, la quantit6 quotidienne de lumi~re dolt intervenir de fa~on d6terminante. La g lande optique est susceptible de garantir le fonctionnement hormonal des mouvements migrato~res. Parrot les moyens d'orientation, l'orientation visuelle d'apr~s le soleil et l'orientation olfactive sont envisag6s favorablement. MIKHMLOV B. N. 1962. On the feeding of the Black Sea medusa Aurelia aurita L. Zool. Zh. Akad. Nauk, SSSR. 41 (2): 286. Species of the organisms entering the composition of phyto- and zooplankton found in the food mass in the medusa Aurelia aurita L. collected in October 1961 in the west half of the Black Sea arc listed in the paper presented. MIYAZAKI M., T. UENO and S. UNOKL 1961. Theoretical investigations of typhoon surges along the Japanese coast (to be continued). Oceanogr. Mag. Tokyo, 13 (1): 51-75. In this manuscript, we have computed the typhoon-surge distributions in Tokyo Bay, Osaka Bay, and Ise Bay by the numerical method. We are based on the hydrodynamic equations and integrate each equation numerically by giving the terms of external forces. The Ise Bay Typhoon in 1959, and some important others, are idealized and used as the typhoon models which induce these external forces. The effects of bottom friction and the Coriolis force are also taken into account. The computed results are thought to be in good agreement with the observed ones. However, we have now many underlying questions which still remain indeterminately. MOCKEL W. 1961. Losses in ships" voyage speed due to tile fouling effect and weather conditions illustrated on the example of three far-range cargo ships. Prate Inst. Morskiego, Gdansk (2 Techn. Ek.spl. Floty), No. 7:27 56 (mimeographed). English summary 97-106. The paper presents the results of over two years' research work in ship operation, carried out by the Ship Model Research Institute in Hamburg with three single-screw cargo vessels, marked ' A,' ' B " and ' C.' Ship ' A ' was employed in liner service to Australia, ' B ' was plying to the West Coast of South America, and ship " C ' (a banana carrier) to West Africa. Within the period of observations ship ' A ' had her screw " 1 ' exchanged for screw ' 2." This allowed to extend the research in question partly also to the influence of the kind of screw on the intensity of losses in service speed. By comparison with additional material on measurements and observations compiled from 33 various ships, the research under discussion has been extended to include the problem of dependency of the weather occasioned losses in speed on the ship's block coefficient. Only those observations and measurements--taken from the three basic ships-~ have been utilized for the purpose of comparative analysis of the effect of fouling and weather factors on speed, which related to the passage of these ships through the common water area of the North Atlantic. To evaluate the data regarding speed losses resulting from fouling and weather factors, the following formula of the index of ship's progress has been applied: ,],,

E~ n" D

.....

whereby : V,--the speed of ship's progress, n - - t h e number of rotations per minute of the propeller screw, D--screw diameter. All the observations from the given ship on her given voyage have been performed with a constant number of screw rotations per minute which roughly corresponds to a constant propulsive efficiency. The measurements taken with ships in their service focussed on fixing the true speed of ship in relation to the water. Owing to the inaccuracy in indications of both mechanical and pressure logs, the data regarding speed have been based on fixes secured by taking astronomic bearings and from the resulting distances of way over the bottom, covered within some fixed periods of time, e.g., every 24 hours. The distances thus calculated underwent corrections as follows: (a) with a view to concluding on the effect of the fouling factor--corrections taken for streams, wind and sea; (b) with a view to concluding on the influence of weather factors corrections taken for streams and fouling of the underwater part of hull. When analysing the influence on speed of the fouling element, only those observations and elements have been taken into account which referred to voyage in nearly windless weather and with nearly smooth sea. With fundamental analysis of the influence of weather factors on speed (wind and sea) only those measurements have been utilized which derive from passages with wind and sea direct forward of the