Radar Navigation, Radar Plotting and Use of ARPA
IMO Model Course 1.07
This course provides training in the basic theory and use of radar for officers in charge of a navigational watch. It is based on the guidance on training in radar observation and plotting and in the operational use of ARPA in Section B-1/12 of the International Convention on Standards of Training. Certification and Watchkeeping for Seafarers, 1978, as amended in 1995 (STCW 1995). This model course aims to meet the minimum training standards in Table A-II/1 of STCW 1995. This guidance superseded the recommendations annexed to Resolutions A. 482(XII) adopted by IMO in 1981.
The various modes of display available and the choice of a suitable mode for a particular application are covered, together with the effect that changes in the course or speed of “own” or target ship cause on the appearance of the display.
The course also covers the recognition of critical targets, the measurement of bearings and distances, and the use of these for fixing the ship’s position and maintaining a plot of the movement of other ships as an aid to collision avoidance. Exercises in the application of the International Regulations for Preventing Collisions at Sea (COLREG) make use of the resulting plots.
A trainee successfully completing this course and meeting the required performance standards will recognize when radar should be in use; will select a suitable mode and range setting for the circumstances; will be able to set the controls for optimal performance; and will be aware of the limitations of the equipment in detecting targets and in terms of accuracy.
When within the range of the coast, the trainee will be able to compare the radar display with the chart, select suitable conspicuous land targets and use these targets to fix his position.
In addition, the trainee will be aware of the need to maintain a continuing plot of ship targets which may pose a potential threat of collision; and he will be able to derive from the plot the necessary information about other ships’ courses, speeds and nearest approaches to enable action to be taken in ample time, in accordance with COLREG to prevent a close-quarters situation arising.
The course is principally intended for candidates for certification as officers in charge of a navigational watch. Before undergoing the course, trainees should have completed a minimum period of six months approved sea service and preferably have gained some experience of bridge watchkeeping.
This section of the course provides training in the basic theory and use of radar and automatic radar plotting aids (ARPA) for officers in charge of a navigational watch on vessels equipped with ARPA. It aims to meet the minimum training standards in Table A-II/1 of the STCW Code.
The methods by which the ARPA acquires targets, tracks them and derives information on their movements are covered in sufficient depth to allow an appreciation of the limitations of detection and accuracy, and the dangers of over-reliance on ARPA.
Other aspects covered include the different types of ARPA in use and their various displays, the content of IMO resolution A.823(19) – Performance standards for automatic radar plotting aids; tests for the malfunctioning of equipment; the effects of inaccuracies in the input of course and speed; the selection of speed input to the ARPA; and the response of the system to changes in course and speed of own-ship or target.
The exercises provide practice in the setting up of the radar; the selection of operational alarms and ARPA facilities, and the use of these to derive information on other ships, i.e. the movement, the ranges at closest points of approach (CPA), and the times to closest points of approach (TCPA); the recognition of potential threats; and the use of ARPA to determine the action to take to avoid close quarters situations in accordance with the International Regulations for Preventing Collisions at Sea (COLREG), and the subsequent monitoring of such actions.
Those who successfully complete this course will be able to choose an appropriate mode of display; select plotting and graphics controls suitable to the circumstances; make appropriate use of operational alarms; acquire and track those targets which present a potential threat of collision; extract the information needed on course, speed and nearest approach to enable early action to be taken to avoid a close quarters situation; and make use of ARPA to confirm and monitor their actions.
They will understand the dangers of over-reliance on the automatic acquisition and tracking of targets and on operational alarms. They will also be aware of the performance standards set out in IMO Assembly Resolution A.823(19), and factors (including errors in course and speed inputs) which may affect the accuracy of derived information; and they will realize the need to check the accuracy of inputs and the correct functioning of the ARPA.
Those wishing to enter this part of the course should have completed a course of training in Radar Navigation and Radar Plotting, and meet the standards of competence specified in Part C1 of this model course.