The Rockland Breakwater is an engineering marvel and a national treasure. I walk it regularly and take pictures there in all weather. Enjoy this site.

From the Breakwater Page on Wikipedia:

The city of Rockland is located on the west side of Penobscot Bay in the Mid Coast region of Maine. Its harbor, long regarded as one of the finest east of Portland, was frequently used in the 19th century as a safe harbor during bad weather. It was less than ideally suited to this task, because its large east-facing opening would still subject ships at anchor to storms with winds from the northeast. Major storms in the 1850s highlighted the need for improved harbor protection, but federal appropriations for a project were not approved until 1880. Between 1880 and 1900 the United States Army Corps of Engineers, under a series of Congressional appropriations, built the breakwater. The lighthouse standing at its end was added in 1902.[2]

The breakwater extends south from Jameson Point (marking the northern point of the harbor mouth), and has a total length of 4,364 feet (1,330 m). It is built out of locally quarried granite, and has a roughly trapezoidal cross-section, its seaward face sloping more gradually than the harbor side, in order to better take the battering of sea waves. The top of the breakwater is about 43 feet (13 m) wide, while its underwater base is an estimated 175 feet (53 m) wide. The visible top is formed out of coursed granite blocks. About 700,000 tons of rock were used in its construction. The breakwater is believed to be unique among Army Corps 19th-century breakwaters in its exclusive use of local materials.[2]

NOTE: I don’t know how they figure it’s 43 feet wide. My guess is more like 15-20 most of the way, widening at the Lighthouse, but if you add the rubble on the east side, maybe.

Links:

Breakwater Web Cam

Breakwater Wikipedia page

Maine Lighthouse Museum

JimDugan.com (owner of this site)