Private equity firm Avista Capital Partners informs it has invested in a newly-formed joint venture (J/V) with SEACOR Tankers Inc., a subsidiary of SEACOR Holdings Inc. that operates a fleet of 7 U.S.-flag Jones Act vessels (5 owned and 2 chartered-in) in the U.S. coastwise trade transporting crude oil, petroleum and specialty chemical products. Under the terms of the joint venture, ACP III Tankers LLC, a wholly owned entity of Avista, will fund a portion of the equity required for the design and construction of three 50,000 deadweight ton product carriers, each with 330,000 barrel cargo capacity, which SEACOR has contracted to build at General Dynamic's National Steel and Shipbuilding Company (NASSCO) shipyard in San Diego…