During the 1950s and 1960s, Maine imagery became the primary focus of Folinsbee's work, particularly scenes of turbulent water and the rocky shoreline along the coast of Maine near Wiscasset, where the Folinsbee purchased a house in 1949. The scene in Off Seguin (Ellingwood Rock) is a grouping of rocks off Seguin Island, a small body of land with Coast Guard Station and a lighthouse perched on it that stands at the mouth of the Kennebec River, five miles off shore. Seguin was a popular summer boat trip, and it featured in many of Folinsbee's paintings from the period (see, for example, Coast Guard Station at Night, JFF.471). When Folinsbee won the Palmer Marine Prize at the National Academy's 127th Annual Exhibition, he remarked, "Now that I've won a marine prize I might as well become a marine painter."
Some have speculated that the presence of turbulent water in Folinsbee's paintings from the 1930s, and particularly in his Maine scenes, is a reflection of a constant threat of danger always lurking beneath its surface. Folinsbee's life was marked by water-borne tragedy early on, but to say that this continued to be reflected in his canvases is the same as saying that Folinsbee's late emphasis on mood was because he was depressed (he wasn't). It is more correct to say that Folinsbee saw in the water what Homer and Bierstadt and Bellows (and others) have seen. That is, the challenge to transfer onto the stillness of canvas the essence of movement, of something constantly in a state of transformation?not only physically, but also in its color and in the way the light is reflected off its ever-changing surface. In Off Seguin, Folinsbee's swift and fluid brushstrokes in greens, blues, and the whites of the spray effectively translate the swells of the waves as they hit the rocks and shore and then recede.