[Fyron]

1) Your ships that have that design strategy will break from formations. Only ships and fighters can ever be in formations. Other things are in the list for no reason I know, other than it might have been possible to code them to be able to go into formation.

2) Sentry means the ships will not be selected with the "select next ship" button. They will desentry when any enemy object is present in the same system, whether it is ship, unit, planet, whatever.