List of monitors of the United States Navy

They were low-freeboard, steam-powered ironclad vessels, with one or two rotating armored turrets, rather than the traditional broadside of guns.

The low freeboard meant that these ships were unsuitable for ocean-going duties and were always at risk of swamping and possible loss, but it reduced the amount of armor required for protection.

World War II all steel 56-foot (17 m)-long Landing Craft Mechanized (LCM-6s) were used as the basic hull to convert into 24 Monitors from 1966-1970.

This was a separate US Navy Mobile Riverine Force from the Swift Boats (PCFs) and PBRs already operating in country.

Ten Program 4 Monitors arrived first in Vietnam, and were armed with one 40mm cannon mounted inside a revolving Mk 52 turret; while the 8 later arriving Program 5 versions (designated Monitor "H") mounted one M49 105mm Howitzer inside a revolving T172 turret.

USS Monadnock (BM-3) crossing the Pacific Ocean in 1898; note how the ship is swamped due to the low-freeboard typical of monitors
The river monitor Neosho .
Casco -class monitors Shawnee and Wassuc .
The Monitor , prototype for an entire class of warship.
The original Puritan .
The "refit" Puritan .
USS Monterey
USS Wyoming
The Keokuk .