Hi all, I'm trying this method right now, although there is a large (what i think is) torpedo net running across the sunken ships. I submerged just before them because i spotted a coastal gun just behind them on the shore. I've taken damage but i think i can quickly surface to get over it then submerge again (I hope that gun doesn't spot me)
Edit: I can safely say this tactic doesn't work (at least in the summer as there is not enough night to work with) after jumping back over that fence by the sunken ships i was spotted by the coastal gun and cornered. Finally I was destroyed in a collision with a Destroyer being pushed up the shore bank, forced to surface to try to break free and fire my deck gun but was destroyed.