Black hole in the water? Heh, best naval tactic ever! "Come and get meeeee!" But yes, naval is purposely slow. It's subject to balance changes though so it could still change.
I kinda like the slow navy. It makes naval warfare feel fundamentally different than the ground war. The ground war can be more re-active. You see someone coming and you react to the threat. The naval war, because your ships are so slow, has to be fairly pro-active. You need to predict what I'm going to do and make your plans accordingly well in advance if you want to actually have ships on hand to confront me. If navy was sped up, it would just be "ground war with big units".