This is a game for one player, and as well as having an arcade appeal, it is also a game of deduction and sensory perception! The scenario is fairly straightforward. You are the captain of a fast sub destroyer and have orders to locate and destroy an enemy submarine in your vicinity. However. you only have a limited amount of time and just ten depth charges. To help you find the submarine you will have to listen carefully to your sonar soundings. When you run the program, the screen display will appear. The computer will then wait for you to either press a key. move the joystick or press the fire button. When you do this, the game will start. The large blue oblong is an aerial view of the sea. The white symbol is your ship. You may cruise around this area of sea but may not leave it. Neither may the submarine. At the bottom of the screen there are two gauges which show the current speed and helm position of your ship. Also shown are the number of depth charges and the time left. To increase the throttle, push the joystick forward (or press the + key). To decrease the throttle, pull the joystick back (or press the ? key). To bear left, push the joystick left (or press the Z key) and to bear right, push the joystick right (or press the X key). Practise manoeuvering your ship. It may take some getting used to and bear in mind that the helm is more sensitive at high speed. At the start the submarine will be out of sonar range. You must search the sea to find where the sub is hiding. Once in range, the sub will reflect the sound pulse of your sonar. You will hear the faint echo shortly after each pulse is sent out. As you home in on the submarine, the delay between the outgoing and incoming pulses will decrease. Also your sonar will automatically start to pulse more frequently. You should learn to judge the range of the submarine by listening to the pause between the outgoing pulse and its echo. More program notes and listing next week. Popular Computing Weekly
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