Occaisional Head Smell

Nov 24, 2014
Catalina 310 Staten Island
Hello all! I have a new 2021 Catalina 315. It has an electric head, fresh water flush, holding tank, and macerator. Normally, the head smells just fine - new boat, in the water for only 2 months - it should smell just fine.

But 3 times now, always while sailing (never while motoring, and not during every sail), the head all of a sudden has a terrible smell. It only smells in the head, as it's not noticeable in the main cabin nor anywhere else. When it happens I see no visible signs of liquid anywhere in the head, and the smell is always gone by the next day. As it has never happened on the dock (despite spending several nights on the boat, and entertaining several times on the boat), and never while motoring, and not even always while sailing, I suspect it's somehow related to sailing at higher heel angles with stronger winds, which somehow causes air/gas to backup through the system. But I really don't know.

Ideas and solutions would be appreciated. Thanks!
Consider yourself lucky. Occasionally my head does NOT smell