This post is about the concept of a transport “overbuild”, by which I mean building more transports than you need to maintain a steady flow of ground troops to your destination. Such an overbuild can be extremely valuable, for reasons to be outlined below.
First, though, a little background. With island nations, the number of troops you can move to the front lines is often limited by your factory. This suggests a natural limit on how many transports you need. In particular, the UK is limited to 8 units per turn, even though it may have money for more if Africa is in Allied hands. This seems to imply that 4 transports is as many as UK can use. Similarly, Japan’s production in its capital is limited to 8/turn; though you will likely build a factory or two on the mainland, you don’t need transports for those, so again it seems that 4 is the most you need.
However, building an extra transport or two can be very helpful. Consider a few reasons why:
–-For the UK:
------Fleet defense. Transports provide fodder if you’re attacked by enemy air, and also make it so they have to kill more before they actually damage your shipping capacity. If you have 6 transports plus your battleship plus the Russian sub plus an American destroyer or two, you can hold off the Luftwaffe without buying a carrier.
------Force projection. This is the crucial reason to overbuild with the UK. Even if you can only ship 8 ground units per turn to the mainland, you can also pick up and move some of last turn’s units. Say you’re typically shipping units into Karelia and then moving them from there. If you have 6 transports, you’re threatening to pick up 4 units from Karelia plus the 8 new ones from UK, and drop all 12 on your target. The key thing to consider here is that adding to your offensive capacity threatens all targets at once! Typically Germany is trying to defend 3 stacks (for example, Weu, Berlin, and Eeu or Berlin, Eeu, and Kar), possibly even 4. If you increase your attack threat by 1 transport, i.e. 2 ground units, then in order for the defense to keep pace they need to add 2 units to all of their stacks. You build your threat by 2 units, they have to increase their defense by 6! Talk about leverage! Now, you might think that this implies you should just keep building transports sky-high: why not have 15, with a pile of 30 ground units threatening the whole coastline? The thing is that you want to be using your ground troops at the same time that you’re threatening the coastline with them. So you keep a stream moving into Europe, and only need an overbuild that can move the “leftovers” from last turn. In practice, I’ve found that 6 is about as much as I can use with the UK.
–----If you move the Australian transport to the Atlantic, it can join your fleet on turn 4 (though it may actually be turn 5; arriving on turn 4 requires stopping in SZ 12 on turn 3, when there may not be other Allied ships there, so you may need to detour around German air threats). This is plenty early enough as it will take that long to have your main transports in place and your ground troops built up to where you can use an overbuild. So you get one of your overbuilt transports for free. Since you start with two, that means you should build 3 transports. UK is the most variable nation in its opening turns, I think, so I won’t even attempt to prescribe when to build those 3. But in general it’s a good pattern to get up to 5 tran fairly early, and 6 when the Australian joins you.
------Here the main reason to get extra transports is so you can get the infantry off those remote islands and/or take things like Australia, New Zealand, Hawaii, and Madagascar. Again, 1-2 extra transports is probably enough.
-----Another possible reason to get extra is if you want to really emphasize the southern route (Fic/India/Persia). If you have 4 transports then you can put 4 units/turn into the south and 4/turn into the north (Manchuria or Buryatia). If you had 6 transports then you can rearrange this to 6/turn in the south and 2 in the north; depending on the strategic circumstances, this may be desirable. (I generally like to emphasize the southern route, but find that dual complexes in Fic and India are enough.)
------Extra transports allow you to get into Africa and the Middle East. You have to anticipate demand here. If you only build up to 4 transports, a turn will come when you want to use the transports in SZ 36 to hit Africa, and suddenly you have a hiccup in your flow of troops to the mainland because those transports were supposed to be shipping new guys across. So make sure to get some extra transports before you make any forays into Africa.
—For the US:
------Unlike Japan and UK, factory production isn’t really a limitation; WUS and EUS together can make 22 units a turn. Instead, you’re limited by your income, which is usually around 38-40 at least for a while.
------Other threads (most recently http://www.axisandallies.org/forums/index.php?topic=14315.0) talk more about US shipping options. I’ll just mention one where an overbuild can be useful. One US approach is to shuck units into UK, and then have a second fleet follow the UK into the Baltic and move units into Europe. In this case, it can be worth having an extra transport in the Baltic fleet. So if you have a 4x4 shuck going, adding a 5th transport to the Baltic can be worth your time; with a 5x5, consider adding a 6th. The main reason is the force projection mentioned above in the UK section. Unlike the UK, however, it takes a while to get an extra transport to the Baltic, so it’s not quite as useful for the US.
Concluding thoughts: I wouldn’t consider going over 4 transports with Japan to be a “true” overbuild, since those transports are being used in different areas from the 4 baseline ones. The UK overbuild is the one I want to emphasize and to recommend the most heartily. When I’m playing Germany, few things make me more uncomfortable than a 5th and 6th British transport!