The developer make this changes:

First, I tracked down a bug that could still cause escort ships to drift away after losing their capital ship.

Second, I balanced out Corvettes and Frigates to have a minimum possible turning speed - Corvettes a bit faster than Frigates. This is a bonus to help them play the roles that I envisioned for them to be screening ships. I noticed that a lot of times these escort vessels could have a really hard time making the turns they needed to make to keep in escort range. So the end result is that you'll see the ships moving at the same speed they normally would, but regardless of how slow or fast they are, they'll have a minimum turning speed to keep them behaving properly.