Sorry! I dont buy that for two reasons.
Sorry was not selling anything, just giving my opinion on how to kill them.
1. To do that all ten ships would have to run my double sub screen on hexside 17:42 to 18:42 twice a day. Once at dusk to enter Gilli Gilli harbour and once at dawn to exit again. The odds of 10 ships doing that twenty times without creating a ripple in a subs periscope don't figure. Not when I'm clocking up one or two sightings a day with single sub patrols elsewhere.
Not hard for Warships to run a sub screen at 30 or so knots, subs are 3 times slower, or the majority are. If you want your subs to catch the warships then put them in Gili Gili, otherwise unless the warship is damaged you may never catch them coming through. I put 4 in Gili and caught them everynight. Of course I lost 4 subs doing this.
2. If they were out at sea beyond LBA range during the day then my convoys heading into Gilli Gilli would be able to make the dash into port during daylight hours. Now I've only tried this once but when I did they ran into the full IJN TF in daylight, in 17:42 and I lost every ship in the convoy.
Sorry have not seen this problem, except for large transports that have to take more then a day to unload. If I use APD or allow retirement then they never get caught by the Japanese fleet. I also have no problem running mine layer into the area during the day.
So! I don't think they move at all. I think they sit in 17:42 day and night but that the program engages a cloak on them during the day to stop them being spotted by LBA. Perhaps to simulate a run out to sea without having to plot it.
I have come across this sort of thing before. Its quite common in the Talonsoft games and comes under the all encompassing umbrella of 'play balancing'. Perhaps without a cloak its just too difficult for the AI to set up bombardment missions that work. I can remeber trying to do it in Carriers at War and it was a pig to organise and time.
Don't know, perhaps they did, but if they are then it is to simulate the actual war because the Japanese did this in the area, GC was the historical area for it. But at any rate we will not know unless a coder states it, of course cheats have to be used for the AI at times just to balance the game.
On a practical note however, if the IJN can run such cloaked missions and sit outside Port Moresby without being detected then what hope is there for stopping them sitting in 17:42 for the rest of the war.
Two big reasons if you use them, Your Surface Task Force, and Your Air Task Force.