French silver boatswain's call with a spherical buoy with a rosette on each side and a scalloped ridge running around it. The long gun is perfectly straight. The keel is shaped as a sea serpent with overall engraved shading, and a three part chain attached to three loops on top. The ends of the chains are attached to a large ring (see also PLT0406 for a smaller call of similar design).

The boatswain's call has a long history both as a symbol of office and as a practical instrument for conveying orders at sea. The call's shrill whistle can be varied in pitch to convey a variety of information, and can be heard above the sound of wind and sea. Such instruments were private possessions rather than official equipment and silver calls like this one made suitable gifts and presentation pieces.