I'm at about 42 - 44 on the NM.
That is close enough to be very concerned with every loss of NM point.
I was concerned about the loss of NM from a naval battle, which could cause an early end to the game. And I am concerned that a unit the size of a corps could be threatened by a computer decision. (The cash investment in the fleet, not including War Supply, is easily equal to that of a quality corps).
This was a bad decision by the computer that could significantly impact the game. As a result VigaBrand suggested he would make an intentional mistake and allow the fleet to largely escape (it did take some hits, resulting in some sinkings).
We are continuing. The fleet is out of the James at the moment and headed for an undisclosed port for repair.
Still, this drew on the players to repair the damage to the game. It shouldn't have been necessary. And, VB's navy was delayed for a turn while it dealt with this rather than the strategic mission it was on.
Regarding the move, it was brilliant. VB built a sizable fleet that is challenging the US Navy across the entire map. And, he did so in secret. I had been steadily building naval units, so I believe I still hold a naval superiority, but I'll need to move with care and concentrate the forces till I can overcome the CSA Navy.
I'll be updating the AAR shortly. The news isn't all bad for the Union. The South has been split at the Mississippi. And that was a rather bloodless victory (that brought no Victory Points). The South has moved a large part of the Eastern armies into Northern Mississippi. There they threaten Western Kentucky, Western Tennessee and of course Memphis.
The conservative strategy you are suggesting is one possible way out for my forces. I'm sure I'll be more conservative moving forward.
As I pointed out to VigaBrand, this is my first PBEM. I've learned a lot of what I shouldn't do here.