Here are some links to pages that describe various LH construction types. The caisson is a very unique method, also used for building bridges. You have to scroll about 3/4 of the way down the CG site to get to caisson. In the NPS site they include a list of caisson lights. Interesting that they include the Harbor of Refuge light as it is built on a
breakwater. Coast Guard Historian NPS Caisson Page NPS LH Construction Types Dave
