238500 MT tanker “TOHKAI MARU” is an energy saving ship equipped with a twin engine (medium-speed PC), a controllable pitch propeller and the IHI super economical shaft generator (SSG MK-II) .
This aid is a microcomputer-based equipment utilizing a graphic CRT display to inform the operator of various effective running data in order to have her highly energy saving propulsion plant operated safely and at high efficiency.

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The presence of time delay in a conventional starting system of a marine large diesel engine makes it difficult to open and close the starting valve at most suitable timing for starting and braking in different engine speed. The time delay occurs mainly in pressure transmission in the pipe of pilot starting air between the starting air distributor and the starting valve.
In a new starting system, ECSS, the time delay is calculated and compensated by electronic controlled circuit so that it can drive the starting valve at most suitable timing for starting and braking respectively, even if the engine speed may change rapidly. The ECSS adapts magnetic valves to the starting air distributor. They are controlled by a micro computer where the engine speed and the crank angle are sampled by using an encoder fitted at the end of cam shaft.
From the result obtained through the test engine (NKK-SEMT 3PC2-5L) experiments, it is proved that the starting performance is improved remarkably compared with the conventional, mechanical starting system. As for braking performance, it is found that the starting valve can be controlled beyond the limitation of conventional effective braking speed.

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A new energy saving pump control system has been developed for ship. This system consists of a cooling sea water pump, control valve of sea water line, microcomputer, transistor inverter, etc. While conventionally the pump is run continuously at a given speed and surplus sea water is supplied with various auxiliary machineries in many conditions, this new developed system provides proper amount of sea water with auxiliary machineries by the control valve and variable speed pump with a microcomputer and transistor inverter.
The first plant of this system was installed on the container ship and we confirmed that the function of this system was satisfactory.

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As the needs for exploration for and development of seabed resources grew in recent years, the sites for such projects have been moving to deeper and deeper waters. As the result, anchors have increasingly lost their usefulness as a means of holding ships in position, and instead, there has been a growing demand for drilling rigs and other structures, etc., equipped with automatic position-keeping devices.
Meanwhile, Mitsui Engineering & Shipbuilding Company has long been making active efforts in the ocean development field, at the same time energetically tackling the ocean electronics field, as a link in its overall ocean-resources development efforts. Such efforts have led to the successful development and production of its own computerized system for dynamic ship-positioning.

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The Koyo Maru, the most advanced cable layer owned by the NIPPON TELEGRAPH & TELEPHONE PUBLIC CORP., incorporates latest technological achievements into her design; Here two systems, ACNAS (Advanced Cable-ship Navigation Aid System) and MICOS (One-man Control System), are reported in details as her typical automatic system.
(1) ACNAS intends to combine and unite the various information such as design route, positioning, course record, target vessel data, degital map and data of cable laying and burying. This system achieved the mechanization of cable laying and burying and data recording works.
(2) According to the change of ship modes (Rest, Stand-by, Work, Navigation), MICOS controls sequentially main engine, auxiliary machines and valves.
These systems realized the remarkable improvement of accuracy, sure operation and labor-saving for cable laying works.

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The Advanced Ships Operation Control System (ASOCS) has been newly developed.
ASOCS is a new type navigation supporting system different from the various automatic navigation systems in the market, and can be installed in not only newly built but also existing ships.
ASOCS has functions to show the ship's optimum operation by correlating the ship data including propulsive performance and main engine characteristics with the sea and weather conditions she encounters.
The functions are as follows.
1. Route planning
2. Optimum sail planning
3. Optimum sail keeping
4. Administration of operation
ASOCS is composed of the two subsystems below.
Operation Control Support Subsystem
Automatic Navigation Subsystem
ASOCS is expected to greatly contribute to the fuel-efficiency of the ship.

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In these several years, the electronics technique has become the leader current at expanded area among control and monitoring system of marine plant, and this will be expected to develop rather quickly toward more higher level and ingenious technique.
On the other hand, it is the real circumstances that the present situation of outfitting, adjustment at shipyard and of handling, management at sea, especially those in engine room do not always give proper circumstances required to the electronic components and equipment.
In order to maintain the adaptability and the reliability of them having in the production stage at manufacturer's factory, this paper is of which announce the general advice or suggestion - from manufacturers to users - on the point of such environmental factors as temperature, humidity, vibration and fluctuation of electric source.

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