The cursor is usually steered by a tracker ball or touch pad in order to:

• Plot WPs and to mark or change them.
• Make measurements on electronic charts. ECDIS requires that the same operations that are performed on paper charts can also be performed on electronic charts, such as reading off courses, measuring distances and plotting fixes using latitude and longitude.
• Gather additional information on a highlighted object.

         ...

The interfaces for ECDIS/ECS differ from those of plotter systems in several ways. ECDIS/ECS systems use one of the common operative systems for computers and just like an ordinary computer this is controlled by menus, keyboard and tracker ball. These may be supplemented with, or replaced by, a manufacturer-specific control box to execute short cuts.
Plotter systems have their own operative systems. Menus and sub-menus are called up by hard and soft keypads and every manufacturer...

SOLAS has set out a timetable for vessels engaged in international voyages to be fitted with ECDIS. After 1st july 2018, all High Speed Ship, passenger vessel > 500 GT, cargo ships and tankers > 3000 GT should be fitted with ECDIS. (Between 1/7 2012 and 1/7 2018 there are different dates for different types of ships) See IMO homepage.

Raster Chart Display Systems, RCDS

All the waters of the globe are not yet covered by official ENCs. When vector chart coverage ...

A number of conditions must be fulfilled if a network of navigational instruments will work properly:

• The instruments must be able to communicate with each other. Signals from sensors can have different formats (analogue, digital and video) and speed (baud rate). This is managed by system settings.
• The connections must be resistant to damage from heat, water and vibrations. Both standardised and manufacturer-specific connectors can be encountered.
• Reliable...

"Navigational systems" is a multi-facetted concept and may embrace rather different arrangements. It has been in use since the 1950s for several systems of land-based transmitters and on-board receivers such as Loran, Decca, etc., and more recently for satellite navigation systems (GNSS) involving satellites, terrestrial monitoring stations and on-board receivers. A wide variety of ship-borne navigational systems are available these days, ranging from certified...

Electronic aids for radar work measure range and bearing.
EBL = Electronic Bearing Line, which can be moved on the screen. VRM = Variable Range Marker. ERBL = Electronic Range and Bearing Line.

IMO demands on accuracy:

Range: within 30 m or 1% of the range scale in use, whichever is greater; 

   

Radar screen with heading line, fixed rings, two EBLs and two VRMs

Bearing: within 1°
The system accuracy of fixed range rings should...

1.  Systematic errors

If the timing of the radar pulse is not synchronised with the timing of the screen the image will be distorted. This can be checked by positioning the ship near a straight object such as a pier. If the echo of the pier is not a straight line then the set needs adjusting. Usually this can be done without the help of a trained engineer.
Directions and bearings will be shown incorrectly if the antenna or HEADING LINE is not properly oriented....

Although radar can detect objects in darkness and fog, it cannot see everything that lies behind the horizon. So under these circumstances low-lying coastlines and other low targets will not return an echo. The radar horizon actually is a little more distant than the optical horizon.

An antenna sited at 4 meters height gives a radar horizon of 4.4 nm. Only objects that project above the radar horizon will be detected by radar. Even radars that have impressive range specifications...

The radar image can be presented in a number of different modes, each with its specific advantages and disadvantages. The image can be oriented with the head line up on the screen (Head Up), with due north pointing up (North Up) or with the vessel's course up (Course Up). Movement can be arranged so that the vessel is always at the image centre (Relative Motion, RM) or with land echoes stationary (True Motion, TM). There are several combinations...

Radar (acronym for RAdio Detection And Ranging) is the most flexible instrument in the Navigator's tool-kit. Radar can deliver a position, a course (as a heading) and a basis for decisions about the risk of collision. On the other hand it is the instrument that demands the greatest degree of competence and work from the Navigator.

Radar measures distance and direction by transmitting a narrow beam of high energy from a continuouslyrotating antenna....

Handlead


The handlead is a wieght at the end of a rope. The rope is marked, usually in two meters interval. (white=2m, blue=4m, red=6m, leather=8m, a string with one knot=10m)Untill 1930th this typ of lead was used for hydrograph survey. Today it may be used for inspection of depth around a ship that has went aground.

Echo sounder
The echo sounder is a useful navigational aid. It transmits pulses of ultrasound (>20000 Hz) and measures the period that...

The ures log speed is an andinstrument /or distancethat . There meas are  many types of log.  Speed can be measured relative to the water surrounding the vessel, Speed Through Water (STW) or relative to the sea bottom, Speed over Ground (SOG).
During harbour manoeuvres one wants to know the speed of the vessel in all directions, fore or aft, and the sideways speed of the bow and stern. Log sensors with two axes can give this information ...