[1] Use of timber rafts loaded with cannon by Danish defenders of Copenhagen against bomb ketches of a combined British-Dutch-Swedish fleet is attested by Nathaniel Uring in 1700.
[2] In 1727, Spanish engineer Juan de Ochoa proposed King Philip V his project of the barcaza-espín ("barge-porcupine"), heavily armored floating batteries moved by rows and fitted with multiple rams.
[3] An early appearance was in 1782 at the Great Siege of Gibraltar, and its invention and usage is attributed to French engineer Jean Le Michaud d'Arçon.
[5] However, Kronstadt was widely regarded as the most heavily fortified naval arsenal in the world throughout most of the 19th-century, continually upgrading its combined defences to meet new changes in technology.
Experimental ironclad vessels that proved too cumbersome or were underpowered were often converted into floating batteries and posted for river and coastal waterway control.