OSM is one of the world's biggest Crewing and Ship Managers, with 30 offices in 13 countries, incl. USA (Houston & Fort Lauderdale) and abt. 500 vessels under management, incl. Offshore vessels of all kinds and their own training centers.
Don't know if this includes any US flag ships, but it certainly involve foreign flag vessels working in the GoM from time to time.
The CEO of OSM is shearing his views on the future of Shipping and Offshore vessel management in today's Splash 24/7: http://splash247.com/osm-shippings-new-reality-demands-fresh-strategies-from-owners/
Most of this may not apply to the business that interest forum members, as the Bayou boys and US Shipping companies are not following the model outlined here, although Crowley is getting into the Shipmanagement business world wide in a big way, I believe.
PS> For US Shipping read; US flag Shipping. Lots of US based Ship Owning companies are using 3rd party Ship management companies, as they are pure financiers.