DISQUS

I have heard of this in the past, but the unexpected 7.3% reduction in power from the original ballast, tank bulk carrier is new news and welcome benefit.

Also, this concept could have prevented relatively recent "Cougar Ace" heel instability and resulting death. Eliminating the machinery related to pumping, filtration, and/or chemical sterilization are certainly advantages, but eliminating the need to disturb your stability while underway will definitely appeals to my KISS principle.

I wonder how frequently other ships have had "incidents" while conducting a ballast exchange?

This looks like a container for transporting used nuclear fuel, also called a mixed oxide (MOX) cask. Here is a link to world-nuclear.org that describes the shipment of these casks and the purpose built ships for transporting spend nuclear fuel; http://www.world-nuclear.org/info/inf39.html .