Mufflers for marine engines

Claim 1

A MUFFLER FOR MARINE ENGINES COMPRISING, AN ELONGATED HOLLOW SHELL COMPOSED OF UPPER AND LOWER SECTIONS FORMING A HOLLOW BODY, THE UPPERMOST OF THE SECTIONS HAVING A PLURALITY OF SPACED, RELATIVELY DEEP INDENTATIONS EXTENDING ACROSS IT AND TRANSVERSELY TO THE LONGITUDINAL AXIS OF THE SHEEL, SAID INDENTATIONS FORMING DOUBLE-WALLED BAFFLES HAVING THEIR WALLS SPACED APART ON THE OUTSIDE OF SAID UPPER SECTION TO FORM AIR SPACES BETWEEN SUCH WALLS, AND GAS EXPANSION CHAMBERS BETWEEN SUCH WALLS ON THE INSIDE SAID BAFFLES EXTENDING ON THE INSIDE OF THE SHELL TO THE CENTER OF THE UPPER SHELL SECTION ON WHICH THEY ARE FORMED, THE LOWER SHELL SECTION HAVING TRANSVERSE INDENTATIONS OF CONSIDERABLY LESS DEPTH THAN THOSE WHICH ARE FORMED IN THE UPPER SECTION, CREATING INLINE OPENINGS BETWEEN THE OUTER PORTS, WHEREBY WATER IS TRAPPED IN THE LOWER SECTION LOCATED BELOW THE TERMINATIONS OF THE BAFFLES IN THE UPPER SECTION.