Hi,
As the term indicates, UAT (User Acceptance Testing) is testing by the user (or owner or customer) or keeping the user's interests in focus. UAT would check the correct implementation of all requirements in the contract.
The entity that has awarded the contract to the company for developing the ship would decide the entity or individuals that would actually perform the UAT. The entity or individuals that would perform the UAT could be any or all of the following:
1. Navy personnel
2. A company hired by the Navy to perform the UAT
3. Contractors hired by the Navy
4. Experts from all the relevant areas
5. External inspectors (who would verify the compliance to applicable laws)
I would imagine that the UAT of the ship could take several months and probably involve a limited number of complex tests (exercises at sea) as well as a number of simple tests (tests of ancillary systems).
Thank you,
Inder P Singh
Blog: Software Testing Space