Thanks Jan for spotting this one, and JapLance for your explanation of how to correct it, I was having this problem too.
And thanks for the Med. Mod
. It's a very different game playing in a small pond (at least compared to The Pacific) and with 10 forward tubes.
The first contact on the first patrol of HMS Tribune was a small convoy containing a Huge-Fast Troop Transport! Looks like some Italian general will be a brigade short.