PORTLAND, Maine — Two and a half centuries ago this spring, Solomon Goodwin brought a six-and-a-half-foot oar crashing down onto David Wilson’s head during an alcohol-fueled argument while the pair rowed a boat up the Kennebec River. The blow did not kill Wilson but it knocked him into the water, where he drowned. A third man in the boat, who had tried to keep the peace, turned Goodwin in to authorities.