Holding Tank
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In order to comply with the waste water regulations in force in some Mediterranean countries an holding tank has been installed in the boat which will enable either direct overboard discharge of waste water into the sea or storage of waste into an holding tank. Discharge of waste from the holding tank is possible through a skin fitting, common to direct discharge from the toilet, using an electric pump (19 Litres per minute).


The holding tank depends on aerobic action to prevent the waste from smelling and to an enable adequate supply of oxygen a 38mm vent was fitted using a Vetus skin fitting. Initially only a single vent will be fitted but the tank has provision to add another vent.

The above image shows the inside view of the 38mm vent before the pipes are connected.


Above first two images shows the layout of pipework to the vent and toilet through the heads shelving. The space taken up by the pipes does not take up too much of the shelf space. The second two images are of the space below the forward bunk with the holding tank base in position. This is held in place at the rear with two hinges so that access can be gained to the space below the tank, should it be necessary to retrieve anything that falls beneath the tank. Note the use of a membrane to reduce the risk of objects sliding under the tank but not preventing any water flowing/draining.


On fitting the tank in place on its base the forward end is prevented from movement athwartships using foam on each corner of the tank. This is ideal because it takes up the shape of the hull and tank. Forward and upward movement is prevented using wooden blocks screwed to the base and aft bulkhead respectively. The third image shows the cable and pipe run through the port sail locker. The vent, toilet in and discharge pipes are run unobtrusively to enable the locker to be used easily and to enable access for pump and pipe maintenance.


Pipes and discharge pump fitted to the tank are shown above. All the pipes shown are above the waterline and are therefore only single clipped.

All valves relating to the holding tank are sited below the sink. The image shows the layout of the valves and the names of the connecting pipes.

The image above shows the pipework complete.

For completeness the image above shows the toilet skin fittings which have double clipped hoses to reduce the risk of the hoses slipping off.

The power supply for the holding tank discharge pump has been taken off the windlass contactor feed. It is unlikely to run both at the same time.

The pictures on the right show the locker space below the heads sink with trim and removable panel. The lower picture shows the pump switch below the sink.

Addition of Deck Discharge (January 2011)

Sailing in the Baltic and across Sweden requires that the holding tank should be capable of emptying via a deck discharge outlet. This was achieved by fitting a two way valve in the discharge pipe and leading the deck discharge up behind the toilet and across the top of the shelf unit to a deck outlet.