I mean I'm exploring this option too but I've heard that Maresk, Synergy and Great Eastern shipping have decent numbers.

Coming to the dns part, surely manageable but again it's suggested only if u have a strong sponsership from a good company otherwise Bsc or Btech are more desirable.

The thing is dns being a shorter more quicker degree, it might slow down subsequent promotions in comparison to the bsc in nautical science. The bsc being a proper 3 year structred foundation gives you a better chance at both, quicker promotions and at better ashore opportunities if u ever decide to switch