Victory's 37VT02 Ballast Placement Slows Roll Period

Victory 37VT02 has a roll period of 3 seconds, 20% slower than the other tugs tested so far (for background read the LNVT Roll Period Theory vs. Reality blog post).   So, why is Victory's roll period longer? Because Victory has an estimated 1,400 lbs of ballast, in the engine room, outboard, and split evenly between the port and starboard sides (see the picture below).

The Port Side of  Victory's engine room.  The ballast is contained behind
the elliptical opening under the battery boxes.

The ballast itself is composed of thousands of ferrous metal punchings.
  

Some of the ferrous metal punchings.   

Because the weight of the punchings is so great and distributed port and starboard, I doubt an owner added it to correct a list.  It's more likely that the punchings were added at the factory in an attempt to build the tug per the blueprints.  Perhaps it was later that the decision was made to move the ballast to the keel.




So, how is the ballast configured on other tugs made about the same time as Victory?  Hiaqua 37VT03 reports having fiberglassed-in ballast in the engine room; how much we don't know.  Raven 37VT04 reports having no ballast in the engine room.  This makes me wonder if what we're seeing is the evolutionary process by which the ballast was moved from the engine room to the keel.

20 June 2015 Update:  Spoke with Tommy Chen today.  He believes that the all the tugs were built with ballast in their keels.   As for Victory's ballast of punchings, Tommy said he never worked used the stuff.