Clear Lake Shores-based Castleman Maritime LLC has been commissioned by Texas tug operator, Signet Maritime LLC, to engineer and design their seventh ASD (Azimuthing Stern Drive) tug. This new 72' LOA x 28' Beam ASD tug is a smaller size, giving her operators improved maneuverability in the tight quarters found on Texas' inland waterways. Upon delivery, the M/V Signet Vigilant will operate from Signet's International Operations Center in Ingleside, Texas. The proximity of Castleman…