A loonnggg time ago I had planned to give the forward heads its own holding tank. After much cutting and grinding I realized that this was going to be more trouble that it was worth. While I accept that holding tanks are a necessity I consider them a major PITA. Having two would just double the experience. In any event I need the space for the bow thruster.
As per LAVAC drawings I had not installed an antiphon valve in the waste hose, this was a mistake. The water siphoned back into the bowl and while it did not overflow it did back-flow waste from the hose with the inevitable smell.
Antiphon valve now installed. All hoses/pump etc. surface installed for ease of maintenance. Wife not majorly impressed but she won't be maintaining it AND its the boy heads.
In keeping with the "boy heads" element it will pump directly overboard (where legal) or back to the holding tank in the engine room. As I hate "Y" valves I have copied this system from another W42.