Silent Service was devised by Sid Meier and published by MicroProse as one of the games that simulated different vehicles and as one of the MicroProse games that became precursors for whole genre. It was the first real simulator of submarine - previous games usually were mix of submarine themes and arcade elements, while in Silent Service we took part in World War 2 aboard one of the US Navy submarines operating on Pacific. There were training mission available, single missions based on historic events or war patrols, in which we had complete freedom where do we want to hunt the enemy forces.
The graphic side was a weak point of the game, of course - after all it was 1985 and even the vector graphics were very simple. Nevertheless the game gave an opportunity to see the world through eyes of the captain of the submarine - while submerged you could use periscope only, there were no sonar screens or anything to help you. While on periscope depth or surface the identification of the targets was available, firing torpedoes or using deck gun (while surfaced). The interface was split into separate screens (bridge, map, periscope, gauges, damages) - a simple solution that was used for many years in further similar simulation games.
Today Silent Service is obsolete with simple graphics, poor sound and not very impressive number of options available, but in 1980s it was a huge deal and the game started the whole genre. Even for those reasons it is important to take a look at Silent Service, another example of Sid Meierís brilliant imagination.