First off:
The weather in SH can sometimes be REMARKable. It's so beautiful to watch, it's nearly insane. However, I have noticed there are close to no clouds unless the layer is at 8/8!
So it's either the full monty or the ultimate piss.
Imagine how (much more) beautiful some sunsets would be if there were cirrus clouds up there reflecting nicely... and imagine the reflection. Oooh.... such fine weather to sink a battleship.
Second off:
Lights. It struck me partly when I dropped a fish at a coastal merchant off Norway a little while ago: While I had to park my sub 300m from the bastard to see it plainly, with the fire burning I could spot it from two kilometers away!!
Then it struck me again when I saw a fishing boat just outside my town. They've got lights, too.
Wouldn't it be relatively sane for neutral ships to carry certain lights aboard?
As a PS now... someone COULD have told me that magnetic detonators are easily triggered in heavy seas.