I think it is fair to state that the USCG recreational standards are in the process of giving way to the ABYC standards. One standard is sorta voluntary (ABYC) depending on your insurance requirements the other is quite limited in scope. In my opinion the next step up in safety is the USCG T-Boat standard. It is required if you are putting more than 6 passengers for hire aboard. >From a practical point of view I appreciate the need for certain safety systems when many lives are at stake and the lack of requirements when only a few are at stake. From a personal point of view and especially if it is MY life at risk I would like to be as safe as is practical. Accordingly I tried to build a 52' boat to the T-Boat standard. I did not succeed ultimately but I have many safety features normally only found on commercial vessels and a significantly degraded fit, finish, and spaciousness. Perverbial trade offs. As far as the differences between ABYC and USCG T-Boat -- my latest copy of the ABYC standards states that Propane lockers must open from the top and that the pressure dials must be visible. Mounting a tank horizontal in a top opening locker would seem to contravene the rules since one could not read the dial. I've never seen a horizontal tank mounted in a top opening locker. My lockers open from the side. It's a small point and I hope I would not be cited by a surveyor. The original question was 'are there places of disagreement between the ABYC and the USCG'. I also know that the members of those organizations think of them selves as simpatico. I simply asked Are they 100%? Edmond Badham COSMO Wilmington, NC