As for the canal, how did you travel through? Did you hear any "Banshee Skreaching"? Like you were running over an anti-sub net? There are none there in FotRSU, if that's what you were using. However, there is one little thing about the game, when it comes to navigating in tight places, like a canal. If you look at the "lay of the land" in the Mission Editor, it actually looks quite a bit like it does on the NavMap, as far as the "jaggies" go:
But notice that I've got the "View" menu open, and selecting the "Render accurate shoreline"? That yields a slightly different picture:
They do not have that in the NavMap view, only the "jaggie" shoreline. Notice how the land and sea are displaced in different places? This is why sometimes, you just have to be on the bridge, personally driving the boat. It just might be that you scraped bottom or the sides in a couple of spots, which is entirely too easy to do if doing Waypoint navigating, especially if you do TC above 8x and don't get to hear all the warning sounds... Myself, I have not tried to go through there, but I will now. Then I might try the Suez, and a few others...

- If you look closely at the map in the ME, you'll notice some "odd" changes from land to water in there, especially the west end of Gatun Lake, and up by Colon, which is where it appears that the adjoining grid was not edited the same, so it might also be that there are "pillars of death" in there, like we had at Truk in an earlier version of FotRSU, which you would not see those, unless on the bridge the whole time.
