OPNAVINST 1710.7a dated 2001 gives the following guidance when passing Washington's tomb:
1281. Ships passing Washington’s Tomb. When a ship of the Navy is passing Washington’s tomb, Mount Vernon, Virginia, between sunrise and sunset, the following ceremonies shall be observed insofar as maybe practicable:
a. The full guard and band shall be paraded, the bell tolled, and the national ensign halfmasted at the beginning of the tolling of the bell.
b. When opposite Washington’s tomb, the guard shall present arms, persons on deck
shall salute, facing in the direction of the tomb, and “Taps’” shall be sounded.
c. The national ensign shall be hoisted to the truck or peak and the tolling shall cease at the last note of “Taps,” after which the National Anthem shall be played.
d. Upon completion of the National Anthem, “Carry on” shall be sounded.
I would add that the signals to render the salute, complete the salute, and to carry on are usually signaled by use of a police whistle sounded on the ship's topside speakers. These whistle blasts are about two seconds in duration and are sounded as one blast for hand salute, two for complete the salute, three blasts for carry on.
Naval vessels passing close aboard as in a channel render passing honors to each other with the junior ship captain initiating the salute and holding it until the senior ship gives the two-whistle signal, and the junior ship signals the carry on to its crew AFTER the senior ship has done the same for its crew.
Maybe you have some appropriate music you would like to play on a boombox or loud hailer.