I remembered that the Rhode Island GIS mapping site was offering free aerial photographs of RI, but I wasn't able to view the pictures since they needed a special program to open them. I finally downloaded the free program, and what a treat! The 1939 photos are surprisingly clear, and the things you can see are just as impressive. And it gets better- you can document a site as it changes! There are photos from a number of years, including 1939, 1951-2, 1962, 1972, 1976, 1981, and so on. There are also high quality color aerial photos (1 meter pixel resolution) from 2003.
Here's a link to the site:
http://www.edc.uri.edu/RIGIS/data/imageryBaseMapsEarthCover.htmlThe "specialized software" you need is either ExpressView Browser Plugin or GeoExpress. I have the Plugin, and once you save and run it, you can just go to the site and click on the portion of the map you want to see. If you have any questions, just post. Oh, the pics uploaded funny, so go to the bottom one and you can scroll l-r.
Here's some pics I got:
Fort Mansfield, with submerged part clearly visible:

Dutch Island, 1939

Dutch Island, closer
