||Capt. P. A. Vergroesen
||Royal College Zeemanshoop
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This book is intended to be a practical guide of measures, which should be taken to evade Tropical Revolving Storms, and if found inadvertently near or in the centre of such a storm, how to "ride it out" with the least possible damage. Only a limited number of the first edition by Captains Vergroesen and Ellens were printed. This was soon regretted as it became evident that this book filled a long felt need. Not only for the traditional navigators of the Merchant and Royal Navies, but also for the steadily increasing number of seamen and workers in other oceanic enterprises. Through their special circumstances they are even more in need of practical guidance about which measures can, and should be taken to minimise the danger and damage a T.R.S. can inflict. This category of mariners is a comparatively new appearance on the high seas and include for instance: International Towing Services; Off-Shore Operations for Oil Production; Drilling Rigs and Drilling Ships and the Logistic Operations. The majority of The units used in these operations are smaller, slower and far less seaworthy than modern cargo and containerships. Through their special circumstances, they have only a limited freedom of movement and are therefore more in need of practical guidance to help them to take the correct measures and make the right decisions, without the need of "time consuming studies." Ships with relatively low power, handicapped by enormous deckloads, or with slow and unwieldly "tows" should, in planning their voyage, set out strategic courses to evade dangerous cyclone areas during the cyclone seasons. A first requirement is noticing the first basic indications. A barometer-reading below normal and an abnormal wind-direction, give the first warning of the presence or the threat of a tropical cyclone. Every trained navigator knows which information is needed, but to compile these and draw conclusions without a "method" is difficult and time consuming. To make this easier, the authors of this booklet have brought all the necessary information of the normal conditions and the regular cyclone tracks together in one chart for each (or part of) month for all tropical cyclone areas. They used information from the weather-maps of the Netherlands Meteorological Institute (KNMI); US Pilot Charts and the British Admiralty Sailing Directions. With the aid of the enclosed models one can determine the ships position relative to the T.R.S., from the abnormal winddirection, the barometer reading below normal, consequently the distance and direction of the storm centre.