The Jones Act is about transporting goods on foreign-flagged vessels to US ports. In the case of Katrina it was waived to allow the importation of oil and petroleum products of foreign-flagged ships. It has little to do with foreign offers of assistance.
For fuck's sake, we know that there are multiple foreign ships operating right now in the Gulf yet you conceded that no waivers have issued. If the Jones Act says what you claim waivers would have had to have issued. Tell me, how can these foreign ships operate without the requisite Jones Act waivers?