Why?
1. Current speed making too much bugs in battle. Like, torping yourself and entering to another ship happening much more than it was with 14 b/s speed.

2. It makes dodging and leaving from battle a lot easier. Even before, it was pretty easy to dodge dreads and cruisers (they had pretty good speed for chasing tho), now its almost impossible to get destroyer by any heavy craft.

3. It makes submarines completely useless. Look - the smaller and weaker your craft the faster and more evasive it will be, but not subs. How it was before - you hunting heavy ships, and if you got destroyer on you, you could try to run from it (torps is useless against it). Now submarines have no chances against it, because they became faster not just in cruise, but in dc (so even diagonal moving will be faster than subs one), so submarine sinking is just time question. They already was weak against destroyers, because depth charges breaking torpedoes placement with 99% chance, that making sub completely useless and it have retreat to base.

I think, destroyers speed should be reduced to 16 - 15 b/s, and being tested on movecraft first, or just return old 14 b/s speed for dc