I hadn't used the anchor in a month or more, and the last place had fabulously stick mud on the bottom. I think the chain brought up most of it and left 1/3 of it under the windlass gypsy, cementing the gypsy to the base. The anchor wouldn't lower and the windlass was tripping its breaker.
I should have taken a photo when I began cleaning--quite a pile of shells, small stones, and cement-like mud were removed. The stones under the gypsy were the main problem.
I don't give up easily, so there is always a manual option. For those of you with Simpson-Lawrence Sprint series windlasses, or any similar model, note that the hause pipe can be revealed by removing just 2 screws on the front cover. The chain can then be brought in or out manually without difficulty. Well, not too much. Padding the front beam with a towel is a good idea.
As for freeing the windlass, a few taps with a light hammer and a simple flossing did the trick. Heavy waterproof grease was applied liberally, assuring that the next opening will be a bit easier.
(In retrospect, since I had to replace the windlass not long after, I think failed bearings contributed to the problem. The second time the windlass jams, replace it. Not that I'm anti-repair, mind you, but in my case corrosion insured the case would not open and the sounds convinced me that there would be a lot of parts to replace.)
"Well it just goes to show you, it's always something."
Rosanna Rosannadanna, SNL