If you’re cruising in the Chesapeake this spring or summer, you may want to think about taking a side trip up the Potomac to visit Washington, DC, a great cruising destination for a long weekend or even more. It may be a well-kept secret, but the nation’s capital is boater-friendly, with several new and revamped marinas, a few within walking distance of some of the most iconic sights in the world. Here’s a story I wrote not long ago for Southern Boating about cruising to Washington. Local construction has improved some of the marinas since then, but all the attractions…