I am the 2010 Training Commodore at Pentagon Sailing Club. I am a retired Surface Warfare Officer (cruisers, destroyers, frigates). I am also a member of Navy Pax River Club, and participated for three years as the Officer-in-Charge of Navy 44s for the Naval Academy's offshore training program. I have several thousand miles of offshore sailing experience (mostly the Ches Bay, Bermuda, New England triangle). I am also a member at Navy Pax Sailing, where I am boat captain of the Navy 44 MK I "Valiant".
As for most respected certifications, as you are aware, there are basically three now: the American Sailing Association (ASA), US Sailing, and Navy Sailing (USNSA). There are some Royal Yachting Association (RYA) affiliations, but they are very few. Any ASA, US Sailing, or Navy Sailing organization, will have a challenge process that you can follow. It will often involve little more than taking a one hour exam, and paying the organization's fee.
I apologize for the long answer, but I see your question a lot.
There are three major sailing clubs in the Washington area that offer floor to ceiling qualifications:
Pentagon Sailing Club (PSC), which is located at Capital Cove Marina on Bolling AFB across from Reagan National Airport. PSC has about 200 member "units". Average turnout for club meetings is about 75. Most of them are active duty or retired military; many are DoD affiliated, with about 25% unaffiliated with DoD. The club has 4 Catalina/Capri 22 boats, with one older Sonic 23 that we keep because she is big and heavy and great for winter sailing. These boats are owned by the club. We have a clubhouse on the back lot of the marina. Our unrestricted sailing ground is the area from the Woodrow Wilson Bridge south of Alexandria to the Fourteenth Street bridge north of the Airport to the Capitol South Bridge on the Anacostia. We have a Racing Squadron that races three of the Capri 22s in the Dangerfield Island Sailing Club (DISC) series on Tuesday nights and on select Saturdays. We offer a B-KBS plus qualification (comparable to ASA 101/103) is required to sail the club boats. As long as the club boats are not being used for the B-KBS course or for racing, they cost $25 to take out for a social sail, or one Frequent Volunteer Sea Mile (FVSM), which are certificates the club gives out for 8 hours of club volunteer work.
For sailing on the Bay, PSC charters from Annapolis Bay Charters (ABC) at Port Annapolis on Back Creek in Annapolis, Maryland. We have approximately 56 day equivalents of sailing on the Bay during the season from April until November. We have raft ups on three day weekends, overnight sails, and trips to remote locations such as Bermuda. To sail as a Bay skipper, you need a D-CS rating in the Navy Sailing system. The club is in the process of implementing an ASA 101/103 concurrent qualification for its B-KBS qualification course.
Navy Pax Sailing Club (NPSC) is based at West Basin on Patuxent River Naval Air Station in Lexington Park, Maryland across from Solomon's Island. The club has about 100 member units, with average club turnout for meetings at 20. Most of the members are NAVAIR civilian employees, with about 40% retired or active duty military. The club has a very nice permanent building owned by Navy Pax MWR. The boats are owned by MWR. They consist of three Catalina 16s, two Catalina 250s, and three former Naval Academy Sail Training Craft (STCs). Two of the STCs are Luders 44 Yawls, which were the Academy's offshore training vessels from 1967 to 1987. The third is a Navy 44 Mk I; this class replaced the Luders Yawls in 1987, and are, in turn, being replaced by the Navy 44 MK II. The sailing area for the Catalina 16s is the local waters between Solomons and Pax River. The Catalina 250s and Luders 44 Yawls can be sailed anywhere on the Bay. The Navy 44 is unrestricted. We offer the ASA 101 course for the Catalina 16 and the ASA 103 for the 250s. We are working on a Navy Sailing based qualification package for the STCs. It will be similar to Pentagon's, but with some signoffs specific to the STCs.
NPSC regular participates in the Southern Maryland Sailing Association (SMSA) races. There is a frostbite series on Sundays in March and November. During the season, the races are on Tuesday night. In addition, there are some all day races to various in the Bay. We regularly participate in Governor's Cup, which is a race from Maryland's current capital (Annapolis) to its former capital (St. Mary's City). It is done on the last weekend of July and starts at 1800 on a Friday and ends whenever the boats get to St. Mary's, which is usually early afternoon. The club also participates in Harborfest in Norfolk, where we take the Yawls down as part of a parade of sail of tall ships. We moor between Harborplace and Nauticus on the restored waterfront. We also take a Yawl and a Navy 44 to the Annapolis Boat Show each year, to support Navy Sailing.
Annapolis Navy Sailing Association (ANSA): I am not a member of this club, but many were active in the Naval Academy volunteer programs. They restarted themselves a couple of years ago, and now have the use of a large cruising boat "Fantasea". They don't have small boats, and are oriented toward ocean cruising. Their certifications are Navy Sailing.
Sailing Club of Washington (SCOW): they are based at the Washington Marina south of National Airport, on the Virginia side. They are co-located with the DISC group. They have, I believe, four Flying Scots and two Catalina 25s. I believe that their qualifications are local. I know little about them.
Chartering:
The sailing qualification card as a "credential" is a chimera. The real truth is that if you are going to try to get another sailing organization to let you take out a boat, they will not be interested in your ASA, US Sailing, or Navy Sailing card. They will want to see your sailing resume. They may want to check your references. They will tend to respond well if you have references from other chartering companies thanking you for returnin their boats in perfect condition. They will view you more favorably if you have been sailing with a sailing club, such as PSC, where other people are "looking at you" than if you have been a private boat owner and can keep your mistakes a secret. Most of the members of the New York Yacht Club and the Cruising Club of America, two of the most respected bodies of offshore sailors anywhere, do not hold a "credential" from ASA, US Sailing, Royal Yachting Association, or Navy Sailing. There is no such thing as a universally recognized "credential".
What the "credential" does for you is show that you went through a structured training program. Combined with lots of on the water experience in an environment where other people have been "looking at you", it paints a picture that instills confidence in the person who will "hand you the keys."