Ill Met by Moonlight - an Indonesian Confrontation Scenario

The date is October 1964. 

The unprovoked sinking of HMS Blackpool by Indonesian naval forces, has resulted in a serious escalation of tensions in the region and an international outcry against the Sukarno regime. The Indonesian government at first denied any responsibility for the act but, under pressure from Moscow, have subsequently admitted firing on the British frigate as an 'act of self defence', claiming that HMS Blackpool opened fire without warning first.

Her Majesty's Government has called for a UN Resolution to condemn the Indonesian attack as a pre-emptive act of war but has resisted calls to escalate tensions further through a retaliatory military strike. However, the Prime Minister and cabinet have secretly discussed the positioning of submarines in Indonesian coastal waters to shadow naval movements and, if the opportunity or need arises, to launch a punitive strike against any Indonesian warships involved in potentially hostile actions.

To reinforce the capability of the 7th Submarine Division in Singapore, the modern attack submarine HMS Oberon has been hastily dispatched to the Far East. On her first patrol, she has taken up position in the Karimata Strait, with orders to shadow Indonesian naval units and to report any hostile military activity. Intelligence has suggested that the Indonesian navy may attempt to land military forces on the western coast of Borneo and may try to seize control of the Karimata Strait as a precursor to a full amphibious landing operation.

In this scenario, HMS Oberon is represented by five contact markers, which may be placed anywhere within the deployment area marked on the map, following the restrictions in the rules for submarine deployment. Her objective is to sink or inflict heavy damage on all of the Indonesian frigates, which have been identified as a hostile threat. The rules of  engagement specify that the frigates must first be detected by sonar or radar, prior to any torpedoes being launched. 

The three Indonesian Riga class frigates, KRI Ngurah Rai, KRI Jos Soedarso and KRI Lambung Mangkurat, are unaware of the submarine threat and begin the scenario with passive sonar. They are deployed as contact counters inside the deployment zone in the SE corner of the map, with their objective being to exit from the NW corner. They should operate as a flotilla formation but may manoeuvre individually once the submarine has been detected by sonar or radar. They may only switch to active sonar and radar mode once passive detection has occurred or after a torpedo attack has been made by HMS Oberon.

The entire map area is shallow water with shoals extending ten centimetres around each of the islands. The scenario takes place at night but in full moonlight, with visual detection range at twelve centimetres. The weather is clear and the sea state is calm. To win a major victory HMS Oberon must sink or heavily damage all three frigates, with a minor victory if at least one frigate is heavily damaged or sunk. If HMS Oberon is heavily damaged it will be a minor defeat with a major defeat if she is destroyed. Any other result will be a draw. The scenario will end when the surviving Indonesian frigates exit from the NW corner or when either the submarine or all of the frigates have been heavily damaged or sunk.