alt Hacker Newsships are less likely to wreck in deep water. Storms can sill overturn them (though if they are unstable getting to deep water is questionable). You mostly expect wrecks from hitting rocks on the bottom. Though in war time sinking happens in deep water.
Too late to edit, but there is one more factor: even in war, the easiest way to find an enemy ship is when it is leaving port. Thus you would expect even in war time the battles are mostly in shallow water just because that is usually what you find around good ports. (Today with radar, satellite and such finding ships at sea isn't nearly as hard, but it is still not easy if the other isn't cooperating)