Nice to see you back for some colourful comments.
That is easy to explain; The Merchant Marine Act of 1920 (better known as the Jones Act) is concerned with transportation of goods between US ports, while the OCS act of 1953 (with modifications) is in respect of activities on the federal OCS, (known as the EEZ per the UNCLOS)
This has been explained so many times here that nobody could miss it. Besides, the text and interpretations are freely available on the net for anybody who care to google it.
The problem is that the two are being mixed up to where the Jones Act is applied to fixed and floating platforms, or even ships operating on the OCS, way outside US territorial waters.
My point in post #98 was that if US owned foreign built CSVs were flagged to US and manned by US citizens they should be allowed to transport the tools and material they need to perform their tasks from a US port, not having to do dangerous ship-to-ship transfers in open sea.
That would create "instant" jobs for US Mariners, not waiting to build vessels capable of doing the task at US yards first.
But of course dumb foreigners cannot see the need to "protect" US jobs by killing the GoM Oil & Gas industry. (Refr. the article in gcaptain newsletter today: http://gcaptain.com/reinterpreting-jones-act-done-deal-not-fast/ and several others before it)
If these vessel will EVER be built they will most likely be foreign designed with foreign machinery and equipment and assembled by mostly foreign workers at US yards, taking years to complete. Meanwhile the US Oil & Gas industry has moved ashore, or abroad.
Good luck to y'll from the dense professor of the most immense brain.