The reality of Pilgrim's Head Plumbing

Note:  To preserve the narrative of Pilgrim's refit this post and diagrams will remain available to readers.  There are design flaws in the plumbing diagrams depicted on this post.  If you are seeking black water diagrams for use on another vessel, then please see our September 30, 2014 post - Holding Tank and Blackwater Plumbing Complete.  Thanks.

Thanks for all your comments and questions on my plumbing schematic for Pilgrim's head.

In the ideal world of plumbing schematics.

Sketching out the system in the 2D world of Google Drawings and actually making the plumbing fit into the space available while conforming to the laws of physics are two very different animals.

I've collected all the components and begun to experiment with the actual installation.  Below is a more accurate image of the routing of plumbing for Pilgrim's head...

The reality of Pilgrim's head plumbing.

With the exception of two changes to hardware, the system above functions identically to the schematic in the original plan.

Comments both on our website, and on the M38 Owners Board inspired me to revisit the possibility of employing the Whale MKV Maunal Pump rather than a Shurflo electric macterator pump.  The Whale MKV pump was part of the Lavac head system on C'est la Vie.  In the 9 years we traveled aboard the pump proved reliable yet simple and relatively easy to service. We already own both the pump and a rebuild kit.

Mounting the pump under the head counter top on the centerline wall works well.  The socket for the removable pump handle will be accessible from the hall outside the head.  This location is eclipsed by the mast when viewed from the salon / galley so I do not believe it will present an eyesore.  If necessary I will fabricate a cover for the handle socket.  This installation places all the pump fittings and the clean out port in easily accessible locations that are also above the waterline.  The drawing above places the pump below the level of the tank discharge.  I plan to install the pump so that it is level with or slightly above the level of the "Y' valve at the exit of the tank.

The second hardware modification is the removal of the 1 1/2" valve at the exit of the tank.  Plumbing the shut off valve between the tank and the "Y" valve splitting the pumpout and the offshore discharge took up a great deal of space.  I believe the "Y" valve will provide enough control to facilitate repairs while mitigating messes. This is the method we used successfully aboard C'est la Vie.

Hopefully this post marks the end of posting plumbing drawings and I will have some images of the installation soon.