All naval decisions are made during this Strategic Phase (yes, we're still in the Strategic Phase) so operations are planned on a two-monthly basis.
The naval game is abstracted but very real, and a very important aspect of the whole game. As with all decisions in the game, the orders for both sides are instigated simultaneously, and conflicts can occur.
The seas and oceans are divided into operational areas; just six of them; North Atlantic, North Sea, Baltic, Western Mediterranean, Eastern Mediterranean and the Black Sea. Each country has naval bases, and ports permitting direct access to an adjacent sea zone, and all naval and maritime units start in a port. Because each operational phase covers two entire months, naval units can actually be sent anywhere accessible. As expected the Black Sea is somewhat isolated. Units sent beyond an adjacent zone can be intercepted en route and may not reach their intended operational area.
Squadrons (read fleets / convoys) are ordered out to sea with a variety of missions; patrol, raider, ASW, anti-shipping, shipping, amphibious, re-base and return. Each unit sent out 'cost' 1 Naval asset point (about an eighth of 1 IP). Each unit can have 1 damage point repaired at this time again at the cost of 1 naval asset point. Merchant marine units can operate as 'shipping' permitting trade, or as 'amphibious' which enables ferrying of land units across the seas. To operate most effectively a sea zone must be controlled by your alliance and thus a string of amphibious units can transport a land unit a long way, e.g. England to Egypt. But, lose control of a sea zone along the way and the whole transfer fails.
Naval units attempt to take control of the sea region they are sent to.
Actual naval combat for the entire two months is now fought out in a somewhat random manner. There is no guarantee that two opposing fleets will meet and fight it out, but they may engage in 'hit and run' several times. Destroyers usually engage subs / U-boats, while U-boats seek out merchant shipping. Damaged units frequently return to port of their own accord. In consequence, the outright destruction of a dreadnought is unusual unless they're hit several sea zones away from base.
Thus if mutually contested a sea zone usually becomes controlled by one side or the other as units retreat back to base.
At the end of this sub-phase you are given a summary screen showing who controls what, and how many of your units remain in each sea zone. You do not know the enemy's strength, if any. Unit counters are placed on the sea zone to indicate possession.
Now, does this work? Yes, far better than I expected, because I've played similar naval zonal games where if a naval unit was at sea it was invariably located and usually destroyed by a larger force. In GoA there is the possibility that units can operate 'by stealth' despite superior enemy forces being present. The frequency of direct contact seems about right. U-boats especially are a real menace to the merchant marine causing damaged shipping to return to port with their holds empty.
For Britain especially, naval operations are vital and expensive. Controlling the seas so trade can come in, and hunting U-boats takes up a lot of time and effort. Securing a troop transport to the Middle East is a significant undertaking requiring planning. Even getting troops across the Channel to France has to be taken seriously for it to be achieved speedily. If severely damaged, a naval unit may be considered just to expensive to repair, and a dreadnought with say 12 damage points takes a minimum of 12 turns, two years to repair. Admiral Beatty's maxim that it was more important to keep the fleet in being than lose it in one afternoon is very true here!
Although as a naval strategy layer this works well, I did have some misgivings. These were mostly cosmetic. I've already mentioned the 'abstracted UK coastline' and arbitrary placement of Scapa Flow, but as regards the latter I was surprised it sits squarely in the North Sea meaning that naval units sent to the North Atlantic have to traverse the North sea, and risk interception there, before reaching the Atlantic. In my view, the whole idea of having Scapa Flow where it was, right up in the north of the British Isles, was because from there it gave direct access to the North Sea, North Atlantic, and Norwegian Sea (herein incorporated as part of the North Sea). I would have been tempted to put this important naval base on the boundary of the North Sea and Atlantic zones, but historically German U-boats DID cause disruption around Scapa, one even sneaking right inside and torpedoing a Battleship. So current naval geometry enforces this vulnerability should Germany countenance challenging in the North Sea.
More importantly, however, the transit to France must be through either the North Sea or the North Atlantic. Fair enough, both zones should be readily controlled by the British fleet, but a U-boat hitting an amphibious transport in the North Sea can send it scurrying back to port, not to its destination! It happens once in a while, and so it forces Britain to expend a lot of, largely wasted, naval effort on securing the sea lanes. This would seem to be historically accurate. Overall though I would have preferred to see a separate sea zone, 'The Channel'. I believe this would have given British transports slightly improved security without diminishing the cost to Britain in naval asset points.
A final complaint! The stacks of naval units at sea cannot at any time be inspected. Not even during this naval phase. The player has to access his naval unit inventory and identify which units are at sea and where. This isn't particularly arduous but some clear graphic would have been much appreciated.
So, overall this is a neat strategic naval game, but graphically it could have been better. 7/10