There are fourteen possible mission types. Your 2IC selects from these, based on your strategy and available forces, when creating missions. The following mission types all involve surface forces except where it is noted that they employ submarines instead. (In SAS, a fleet can not contain both submarines and surface ships).
In this mission type a fleet that includes one or more aircraft carriers will be sent out to attack one or more enemy ports with aircraft from the carriers. The ports will be selected either by your 2IC or by you. The aircraft will attempt to damage not only infrastructure at the port, including RP storages, but also enemy ships in harbour. The fleet will come just close enough to the port to be in attack range by its own aircaft, but no closer.
This is similar to a aerial bombardment mission except that the fleet will be composed of ships intended to use naval guns for bombardment. (In SAS, this excludes submarines and aircraft carriers). The fleet will sail into an adjacent hex to an enemy port that has been selected as an appropriate target.
In this mission type the fleet will typically be very powerfully composed and will sail "into the lion's den", relatively close to an enemy port, and will patrol there waiting to intercept enemy ships attempting to sail into or out of the port. The port will have been selected either by your 2IC or you.
In this mission, one or more fleets will have orders to sail to a hex adjacent to the port to be assaulted, offload any troops and perform a preliminary bombardment. In missions of this type set up by your 2IC, the fleet(s) will arrive at a time that allows for a pre-dawn bombardment. When several fleets are involved they will sail from different points and converge on the enemy port at the same time. The land battle may take some time to resolve or it may be very quick. When the battle is resolved, if the assault is successful, the enemy port and all its remaining facilities as well as any enemy ships in the harbour come under your control and can be used like any other of your ports and ships. If the assault is unsuccessful, all remaining troops from your assaulting units are captured.
If the port is the enemy's home port, a successful assault signifies that you have won the game.
The combined operations mission is the most complex of all as it can involve the coordination of several fleets plus any ground forces able to reach the target by land.
Your 2IC does a lot of complex planning when preparing a combined ops mission for you!
Note:Combined ops missions are not possible on the first turn of the game. Although you can always manually create your own amphibious assaults, your 2IC (as well as your computer opponent) will desist from planning combined ops missions on the first game turn. This is because, at the start of the game, your 2IC does not consider he yet has enough intelligence of enemy troop dispositions to sensibly plan. After the first turn however, your 2IC will have intelligence (of varying quality - depending on the level of you enemy intelligence) which he can use to plan combined ops missions.
A convoy is any fleet with at least one ship carrying raw materials, troops or supplies and that is sailing between your own ports, loading and unloading as it goes. The carrying will usually be done by merchant ships; but naval vessels can also carry troops and supplies (but not raw materials) when needed.
The ports can be selected either by your 2IC or you. If your 2IC is creating the mission, the ports will be selected according to need as well as profit. Need is determined by a calculation of the supply needs of a port (eg to support troop garrisons or to refuel, rearm or repairing your ships) compared to the current supply stocks. Profit is determined by calculating the value of routes between ports basd on the length of the route and the value of the cargo. (Typically, convoys will be plannned between rich sources of raw materials and ports with the industry to profitably process them. The shorter the route, the more valuable it is also, because more trips can be made in the same time).
If resource points (RPs) are your lifeblood in SAS, convoys are the main arteries that carry the ingredients necessary for making RPs and transporting them to where they are needed.
Convoys are typically relatively slow, and usually will include escorting naval ships to protect the merchants ships from aerial, surface and submarine attack.
In a defensive patrol mission, the fleet will be given one or more hexes to patrol. The hexes are set either by your 2IC or you. The fleet will usually have aggressive orders to intercept enemy fleets it encounters. Defensive patrols are useful to establishing defensive lines to secure important rear areas, such as your key ports or convoy routes.
This is the same as a defensive patrol mission, but has submarines only.
Ships that can lay mines (which in SAS means only escort ships) are tasked to lay them in nominated hexes. The hexes are specified either by your 2IC or you. The hexes will typically be chosen so that they form a defensive perimeter around your ports.
This is similar to a defensive patrol except that the patrol hexes will be inside enemy controlled sealanes, usually in areas that interdict key enemy convoy routes. The fleet will usually be given cautious attack orders.
This is the same as an offensive patrol mission, but has submarines only.
This is the same as a defensive minelaying mission except that the hexes to lay mines in will be inside enemy controlled sealanes, such as on major enemy convoy routes, or close to enemy ports.
In a ready reaction mission, the fleet will remain in port but with orders to aggressively sally and attack any enemy fleets that come too close.
A reconnaisance mission is like an offensive patrol but the fleet's orders will be to always avoid battle if possible. (Offensive patrols with rules of engagement like 'Hit and Run' can perform reconnaissance but can also be of some offensive use. Pure reconnaissance missions will typically contain a small number of fast ships, like fast cruisers, that can use their seaplanes for scouting and usually be fast enough to avoid battle).
A troop transport mission is one in which ships capable of caryying roops are tasked with transporting a required number and type of troops from a place where there is sufficient surplus to one where there is a greater need to bolster the garrison.
The number of troops and the pors of embarkation and disembarkation ar selected by the computer based on where troops are currently distributed compared to where they are most needed for defence, as well as on where suitable transport is available.