Holding Tank On Eriu

Without getting embroiled in the “Holding Tank” controversy, I decided that I needed
a HT in Eriu for the following reasons;

1. To permit the OCCASIONAL use of the heads while in a
Marina etc.

2. To permit the treatment of sewage (with a bio type additive), prior
to dumping it, when and where this is permitted.

3. To satisfy the legal requirements of having a HT.

The criteria for such a device were simple;

1. It had to take up as little space as possible while still being practical.

2. It had to be idiot proof.

3. There had to be a minimum risk of smells.

After much consideration the following plan was adopted;

1. An “in line” holding tank design was adopted (see diagram below). I had
first seen this on a charter boat. The HT is brought into use by simply
closing the existing waste outlet tru-hull.

2. The locker above the sink was to be used to store the tank (Raritan
Mold # 10B278 – 10 Gal – US$156) fits perfectly once you remove the shelf.
(Contact Vic at Raritan 800 352 5630 – superb service).
There is plenty space to store the usual bathroom stuff afterwards.
After much discussion 10gals (about 10 flushes) was considered adequate
as I have little interest in sailing around with raw sewage onboard.

3. The deck pump-out connection would be installed at a later date. (If I ever
live in a place with a working pump-out station).

4. The tank vent would be lead all the way to the stern to prevent any smells
entering the cockpit area. This may sound like overkill but it works well.
An inline filter could also be installed directly to deck level.

THERE IS ONE WORD OF CAUTION WITH THIS SYSTEM – Nothing (INCLUDING TOILET PAPER) can be put in the head, unless you have eaten it first. Paper will solidify in the tank and block the exit (easy to clean but unpleasant). This has never been a problem on ERIU as all such items go into a little brown bag for subsequent disposal.

While I was at it I decide to replace the Raritan heads with a Lavac model as I firmly believe that only the British make good marine toilets (they have to be good at something). This system, however, should work with any heads.


Holding Diagram

Pictures as follows;

Note handle insert for lavac pump, on the right hand side.


Connections from R to L, Waste Inlet – Inspection Plate – Deck pump-out (blanked off) – Vent to stern.


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