Herbert 'Ocean Hobo' has a holding tank in each head.
They are take up the whole space below the towel rails alongside the sink and cover some of the cave lockers (although you can still just get a hand into the space that is left). Each tank is around 70 litres with a tank watch and electric macerate pump out. I had thought there was something in the archives about it from Ken Knight who installed them when he owned the boat.
The system has two diverted valves for Sea/Tank and to Fill/Empty the tank. This increases the amount of pipe work and the additional hazard of blockage and cleaning out. I am tempted to remove the first divert valve and just go direct to tank and then pump out to sea.
I can send some photos if you want. I am just in the process of replacing the original foam backed wall covering with plastic shower panelling.
