The word is buoy.
Those objects are called "buoys." Buoys are typically floating markers that help guide ships, boats, and other watercraft by marking navigational hazards, anchorage points, or underwater obstacles.
Douglas Ward has written: 'Berlitz 2000 Complete Guide to Cruising & Cruise Ships' 'Berlitz Complete Guide to Cruising and Cruise Ships (Berlitz Complete Guide to Cruising & Cruise Ships)' 'Berlitz 98 Complete Guide to Cruising and Cruise Ships (Serial)' 'Local associations eye instruction and professional development' -- subject(s): Education, Societies 'Berlitz 2005 Ocean Cruising & Cruise Ships (Berlitz Complete Guide to Cruising and Cruise Ships)' 'Berlitz Complete Guide to Cruising and Cruise Ships 2002 (Berlitz Complete Guide to Cruising and Cruise Ships, 2002)' -- subject(s): Guidebooks, Cruise ships, Ocean travel 'Berlitz 2007 Complete Guide to Cruising & Cruise Ships (Berlitz Complete Guide to Cruising and Cruise Ships)'
Give the meaning. Demonstrate the setting for the operational warning
floating islands
A floating sign for ships is a navigational aid that floats on water to provide information or warnings to mariners. These signs can include buoys, beacons, or floating markers, and they are used to mark channels, hazards, or other important maritime locations for safe navigation.
because they are so fraking large (some ships go for a kilometere)
They thought that the conquistadors were metal platted beasts and the ships were floating mountains.
Navigate
a light house
Sextant
ships or some type of floating thing
An amount whose weight is the same as the sum of the weights of all the ships that are presently floating,