Which ship in whose Navy had an ILS localizer on board? Did it tow marker
beacons, too?

SPN41, equivalent to ILS. A godsend when it got ugly and/or dark.

Yes, those plane guard helos had a hell of a time maintaining position with
their marker beacons, heh, heh, heh.

Obviously, we were limited to DME only, assuming it was radiating. But
given the nature of the beast, you knew pretty much where you were by
altitude.

R / John