maintenance under water is a bitch.

As is off-shore oil platform maintenance.  Companies supplying divers for the oil industry could supply divers for these facilities.  Hopefully, the East River Project will provide information on that issue.  It may prove possible to remove-repair-reinstall.  For some aspects tidal estuaries seem worst case, but at least, in this case, they are close to shore.

If sanity be culturally normative, then by the norms of this culture I claim insanity.