“Running a Line Heating Work” Video
Line Heating Work in Japan
Sanwa Dock Co., Ltd.
First of all, you're probably wondering, “What is line heating work in Japan'?” Let me explain what is involved exactly.
Ships are built by piling layers upon layers of outer plates. These outer plates come in geometrically different shapes: one-, two-, and three-dimensional. One-dimensional plates are flat boards, two-dimensional plates are curved either vertically or horizontally, and three-dimensional plates consist of various types: those combining vertical and horizontal curves, dished plates, saddle-shaped plates, and plates which are a combination of all of these. There are some boards that are even twisted, which is why the outer plates of ships are very complicated.
In Japan, line heating work refers mainly to the machining of three-dimensional curved outer plates. The work is broadly comprised of two processes: cold work and hot bending work. Cold work is the process of bending sheet steel using mainly pressing machines. Hot work involves bending the sheet steel by utilizing the property that it shrinks during cooling after heating the sheet with gas. In Japan, this hot bending work is regarded as craftsmanship.
In the narrow sense of the word, we call hot bending “line heating work.” The video I will show you shortly introduces the line heating work process. Before going into that, let me explain the percentage of bent plates used for ships. In Japan, for large ships, bent outer plates account for about 30% of all plates used. For small- to medium-sized ships, 60% to 70% of all outer plates are this type, in some cases up to 90%. Note that these figures are rough estimates, and the actual number differs according to ship type, or the speed of the ship. For example, for large passenger ships, the percentage is 40% to 45%. So the higher the speed of the ship, in other words: the faster the ship, the more bent plates are used. Between tankers and RO/RO ships of the same size, RO/RO ships use more bent outer plates, because the ship form is determined hydro-dynamically.
In Japan, the history of the development of line heating work coincides with that of the establishment of welding technology and progress of ship variety. Let me talk briefly about the history of line heating work here. Around 1945 and onwards, the first line heating work developed from a type of work called furnace work. Furnace work involves heating sheet steel in a furnace until it becomes red, and hitting the hot sheet steel with a hammer, etc. to the desired shape. Technicians found that hot sheet steel bends when wet to cool during this process and later they became the pioneers of line heating work. In the next twenty years from then, this technique spread to the rest of Japan. The infrastructure for line heating work was completed in a decade starting about 1965. The line heating work technicians of this time are the masters of line heating work today.
The first ship built by the welding block method was the “Shinwa Maru” built in 1948. The welding technique allowed bent outer plates.
The first wave-less hull form in Japan was realized by the “Kurenai Maru” built in 1959. The wave-less hull is designed to use its bulbous bow to dissipate waves at the bow. The establishment of the line heating work technique underlies the development of the bow shape of ship. Ships built after this were all designed with bulbous bow.
The first super tankers in Japan were the “Nissho Maru” (with 100,000 DW) built in 1962 and the “Idemitsu Maru” (with 200,000 DW) built in 1967. Both were realized by the welding block method and wave-less hull form (bulbous bow). Supporting these two techniques is line heating work.
For these reasons, line heating work is a skill unique to shipbuilding technology, and one which is indeed crucial to this industry.
USE OF RO-RO SHIPS IN THAILAND
- Project for Promotion of The Modal Shift in Thailand -
Masahiro UESONO, JETRO Singapore
The Kingdom of Thailand has established its position in the world as a moderately industrialized country. On the other hand, as a result of the speedy growth of its national economy, various problems such as increasing income differential among regions and economic activities polarized exclusively to Bangkok which consequently generate heavy traffic jams have emerged.
At present, 90% of Thai domestic freight is moved by truck, often on overloaded vehicles that cause serious damage to the road system and impose a major cost on the Thai government. In addition, heavy vehicles contribute significantly to traffic congestion, greenhouse gas emission, atmospheric pollution, and noise and vibration problems.
It is therefore expected that the establishment of a balanced transportation system would make an important contribution to both economic and environmental objectives.
The Japan External Trade Organization (JETRO) Singapore Center has studied the Modal Shift in Thailand with the cooperation of Ministry of Transport of Thailand, Thai Maritime Navigation Co., Ltd., and The Cooperative Association of Japanese Shipbuilders (CAJS) for more than 3 years.
2 POTENTIAL OF COASTAL SHIPPING IN THAILAND
Of the road freight task, which currently stands at nearly 400 million tons per annum, approximately 13% ― roughly 50 million tons ― flows in corridors in which coastal shipping could conceivably be a competitive alternative. A comparison with the scale of the current coastal shipping task shows clearly the magnitude of the opportunity presented here. If we exclude bulk petroleum, which is largely captive to coastal shipping and uses services dedicated entirely to this task, the total volume of cargo moved by coastal shipping at present is approximately 1.2 million tons per year. The total scale of the potential new market is therefore nearly 40 times the volume of non-petroleum cargoes carried by coastal shipping.
It would, of course, not be realistic to assume that this potential market could entirely be captured by coastal shipping. However, even a five per cent penetration would triple the current quantity of non-petroleum cargoes carried by coastal shipping.
As mentioned above, the expected potential volume of cargo moved by coastal shipping is obviously sound and existing, and it is clear that the transfer of cargoes from road to sea offers the greatest opportunities for future growth of the coastal shipping industry.
3 MERITS OF RO-RO VESSELS
“Modal Shift” is generally known as a shift in the transportation mode to a more suitable transportation system aimed at improving the conventional transportation mode based on properties of cargoes and passengers. In reality, it is commonly understood to mean shifting from road transportation to water or railway transportation.
To achieve an effective modal shift, which will in turn result in the improving of the cargo carrying capacity and usability of marine and railway transportation, it is essential to ensure smooth operations at inter-modal junctions. Using multiple transportation systems typically entails a great deal of time and cost in loading and unloading cargoes. Minimizing these factors is essential to physical distribution efficiency and is the goal of modal shift.
Under such circumstances, roll-on roll-off (RO-RO) vessels are being utilized in maritime transportation globally and are commonly known as one of the best inter-modal transport systems in conjunction with road networks.
RO-RO vessels also provide significant advantages in cargo care, since cargoes can remain aboard a road trailer for the full journey and avoid both multiple handling operations and minimize exposure to damage during the actual element of transportation by sea.
4 MEANING OF INTRODUCING THE RO-RO VESSEL INTO THAILAND
RO-RO vessels are more suited to a common carrier role, carrying higher value cargoes that travel in smaller parcels, and for which transit times and/or delivery deadlines are particularly important. Presently, cargoes of this type are carried almost entirely by road in Thailand. The successful introduction of coastal RO-RO services in Thailand, therefore has the potential to achieve significant external benefits through the reduction of congestion, air pollution and road maintenance costs.