I've run the last few patrols with only the single barrel 40MM AA guns. Thinking I really wanted those twins, I experimented as follows:
1. In Port (the Office after my last mission completed), loaded an Aft Twin 40 with a single barrel 40 at the fore position, launched a new patrol from outside the port, manned the Aft Twin 40mm gun and test fired into the air. Worked fine. Reloaded the previous Office.
2. Replaced the Aft Twin 40 with a single and replaced the Fore AA single 40mm with a Twin 40, launched the same patrol (to recon Tokyo harbor) from outside the port, performed a test fire of the Twin 40 into the air. Again, worked fine. So I go back and reload the same Office I started with.
3. Next I replace both fore and aft single 40mms with Twin 40's. I launch the recon patrol for the third time, test fire both AA guns from the patrol starting position, and they work just fine! Ah, sweet victory.
4. Now I load the Office (in Port) that I started with, Add the Twin 40's (at 1,000 renown each time I add one), save the configuration with the twin 40's, start the patrol, and move about 60Nm off Midway, a point I like to use to make a cautionary save before starting across the Pacific. Feeling brave, I have the crew man the AA guns as before, go myself to the Aft gun, and test fire. Immediate CTD! The last time I reported a CTD it was at the point of firing the Fore AA gun, so position doesn't seem to be a factor.
So why should it work at the patrol start position (outside the harbor) but CTD 60 Nm out of port? Sure would like to see someone diagnose this one. You can see my current configuration in my signature.
On the subject of the Tokyo recon mission, while the written orders say to recon Tokyo harbor and take pictures if possible, the actual destination shown on the mission map is quite a bit south of Tokyo. The target destination Star is on Yaizu, about 95 miles south of the entrance to Tokyo Bay. Just thought you'd like to know.