It is for this reason that this marine accidents inquiry agency insists on the importance of the investigation of external forces exerted by waves and swells, as well as accurate calculations of ship strength.
3] We do not need to speak at length about the fact that ships should be able to respond to many situations. In the past, when fishing vessels, which used to be built with wood, came to be constructed with steel, crew members on board such ships dared to continue sailing even in rough weather, with a vague, false belief that steel ships by definition would be okay. Many of these vessels encountered accidents over time. Even if a vessel has become large in size, the dimensions of structural members have not increased proportionately and there are cases where, in seas with a wave length of 200 to 300 m, huge vessels may rather be exposed to danger. It goes without saying that even huge vessels must, in heavy weather, take such measures as the alteration of course and reduction of speed, as necessary.
It can be positively recognized that on board the "Bolivar Maru", after having entered the area of strong seasonal winds when she came closer to Japan on the voyage of the casualty, not to mention during the encounter with Typhoon No. 21, the handle notch of the engine speed was lowered several times out of prudent consideration since the heavy weather was considerably severe, as expected every year in the winter North Pacific Ocean.
The forecast made by the Meteorological Agency will not always be correct and at times the prediction of the course of a typhoon, as to whether it will pass on the right side or left side of a ship's course, or on a collision course, is extremely difficult to determine until after it comes very close to the ship. Accordingly, it is often experienced that the master of a vessel has no time to study a typhoon carefully or is troubled by incorrect foreign weather reports. In such a situation, even if the vessel enters a storm area, the master will be able to properly maneuver her with confidence if he has a clear idea about her hull strength and, hence, crew members will be able to devote themselves to the carriage of goods with peace of mind.
Today when the size of vessels has grown so huge, shipbuilders are expected to submit specific data for judging hull strength against winds and waves anticipated by ships and make arrangements to maintain close communication between designers and operators, thereby sweeping away any anxiety felt by crew members.
4] As for electrolytic protection of ballast tanks, etc., it is necessary to inspect its effectiveness at regular intervals and whenever necessary in order to grasp a clear picture of protection against corrosion and, if required, replacement should be made with paint coatings whose performance is well known, or any other improved method of electrolytic protection.
Taking notice of this point, Nippon Kaiji Kyokai, or the Japanese ship classification society, set standards for the required scope of coating and electrolytic protection and notified its branch chiefs with circular No.71 HC5RZ on January 19, 1971 and, furthermore, concerning their handling, with circular No.71HC54RZ "Handling Procedures of Coating and Electrolytic Protection of Ballast Tanks, etc."
