Re: Why a submarine?
25 meters may NOT be deep enough, FYI. Heavy seas at 100 foot keel depth were more than just noticeable as I recall. And if your navi-guession system can't handle taking 20 degree rolls every 2 seconds at that depth, and still compensate 'dead reckoning' so you do not go off course (it's too deep for GPS and radio navi-guession without a trailing wire antenna that would pose yet another navigation hazard to other ships in the area), then you could end up crashing into rocks or hitting a sea mountain without a whole lot of warning.
And constantly pinging with active sonar will only do you so much good.
If I wanted to build a ship that is incredibly hard to capsize and/or sink in bad weather I would build a catamaran or trimaran. But existing cargo shipping design is still pretty good.
There are just SO many difficult-to-solve problems involving sub design vs surface ships. Just the trim and drain system ALONE (to deal with neutral bouyancy as part of depth control) is a huge part of it, with trim tanks, fixed and variable ballast tanks, emergency blow systems, low pressure blow systems, yotta yotta yotta.
Biting the hand that feeds IT
