Tuesday, November 13, 2012

Another project done: head plumbing

Yet another boat project post.  Sorry, no pictures of warm, blue, inviting water.  If you're interested in those stories, please look back to my travels last year for some beautiful blue warm waters.  Or better yet, read one of the blog's from people out there now, such as SockdolagerEstrellita 5.10bSwell or Alex and Taru.

Also, note that I use this blog as a way of keeping track of my records so that if I need to refer back to how I approached some project I did in the past, I have a record of its details handy.  I don't expect everybody to be as fascinated by these stories as I am.  With that said, onward.

While I was preparing to leave Hawaii one of the last things I did was to ensure that my head Y-valve was moving freely.  The Y-valve is used to direct the head's 'black water' to either the holding tank or to a seacock in the hull so that it can go directly to the ocean.  While on passages, I have the head pump directly offshore rather than into the holding tank.  So, I was going through my departure checklist and went to make sure the Y-valve could move.  Much to my surprise, the Y-valve's handle broke off in my hand as I tested diverting it from the holding tank to offshore.  After swearing is surprise, and then swearing some more, I realized that fixing this little incident was going to be rather painful but that it could safely be left to much later.  Well, that much later started a couple of weeks ago and just finished.

Look Ma, no handle!
(Note that the picture above was taken after removing the hose clamps which are normally there.  I realized at the last minute that I almost missed an opportunity to amaze my readers with an incredible project photo and snapped it during disassembly.)

For avid readers of this blog, you may recall how much I enjoyed removing the original head hose and installing the hose that has been in the boat for the last couple of years, as described in this old post.

The general layout related to this project is shown below.

The black water runs from the head up the hose at the back on the left to a vented loop, then down to the top of the Y-valve and either down to the left to the holding tank or to the right directly to the ocean.  The vented loop is below.

Vented loops need to be installed high.  One of the problems with the installation I had was that the vented loop was installed high in the cabinet behind the head beneath the cap-rail, which also turned out to be behind the ducting for my forced air furnace.  Its location meant that the vented loop was pretty much inaccessible.  You'll notice on the picture above that the vented loop has a removable cap on the right.  This cap contains a little valve that should be cleaned and inspected periodically.  You can guess how often this happened in my installation.  The valve failed sometime last year and as a result I would now and then get black water escaping out of the vented loop and dribbling down an adjacent hose.  This wasn't a pretty sight.

A second more subtle problem with the previous installation is in the hose from the Y-valve to the holding tank.  It heads down from the Y-valve and then up again to the entry to the holding tank.  This loop of hose would pretty much constantly contain black water from the head as it is 'uphill' to the holding tank inlet.  I've since read that its much better if the plumbing can be self-draining, that is all of the hoses are normally empty.  If you can design the system this way the hose will remain odor free longer.

So, similar to the sink project, I wasn't sure how I was going to solve all of the related issues, but the first step is to rip out what I had so that I could make progress.  Since the hose I had previously installed fit so snuggly onto all of the different hose barbs and inlets I had to cut the hose off.  Doing this meant that I couldn't reuse any of the old hose.  So I cut the hose off, pulled the vented loop down and freed it as well.  At this point I could verify that the vented loop was the cause of the black-water-dribbling problem and that the valve had completely failed.

I wanted the vented loop to be more easily maintainable and the only way I could think of solving that was to make it easily accessible, and only place I could picture that happening was outside of the cabinet, external and visible.  I didn't like this so much as I thought it would be ugly but in the end, I chose Function over Form and now that its all done I see the beauty inherent in an easily maintainable system.  This decision meant that I would need to drill two large holes in the counter top - it was a bit of a Bold Move.

The proposed area, without any holes drilled yet
Before drilling any holes I needed to decide how large to drill them.  The hose I had been using was Sealand Odor Safe Plus, and it is a bear to work with.  I just hated the idea of working with it again, its very stiff and extremely difficult to get onto all the different fittings it needs to fit onto.  Also once its on you have to cut it off, and it would be much better if the hose could be removed every few years and pounded on a dock somewhere to remove the scale which builds up inside it.  I did some reading and discovered that there seem to be two leading sanitation hoses - the one I had used last time and Trident 101 sanitation hose.  They both have a 5 year warranty against odor failure which shows both manufactures are pretty confident in their product.  I found some of this hose at Fisheries Supply and bought a 3 foot segment.  It was very bendable and fit onto all of the various inlets and hose barbs easily.  I decided to use the Trident hose and having worked with it now, would chose it over the Odorsafe hose every time.  The outside diameter of the Trident hose is larger than the hose I had been using.  I found a larger hose which had an inside diameter that would hold the Trident 101 and bought a short segment of this to be used as a chafe guard.  Time to start drilling.

First hole cut
which eventually lead to:

Two holes and chafe guards
To mount the vented loop above the two holes I had drilled, I needed a mounting plate.  I had some teak from a previous project, so I cut a square of it and shaped it into a triangle that the vented loop would fit onto.  I teak oiled the wood, drilled the mounting holes in the wood and then used 3M 4200 to bond the teak to the wall.  I used 1" nylon spacers to hold the vented loop slightly off of the teak.  From here on its simply a matter of fitting the hose, cutting it, re-fitting and clamping.  This last part went very quickly.  Or it would have gone very quickly if I had planned a little better and had enough clamps of the proper size (larger than the old clamps were) and had decided on the best routing of the hose before cutting (oops,) it actually took me a leisurely 3 days to finish up.

My new beautiful vented loop.  Look how easy it will be to maintain!
Behind the head I changed the geometry of where the Y-valve was mounted and have a setup in which all the hoses that could possibly self-drain, do self-drain.

You may notice that the Y-valve is no longer mounted at all.  I tried to mount it in its old location on the hull but the hose just wasn't making it easy.  The hose from the vented loop through the counter top to the top of the Y-valve just wasn't going to bend into place and the hose from the Y-valve to the holding tank inlet would be uphill again.  The three hoses the Y-valve is clamped to are all sturdy and pretty inflexible.  It turns out that the Y-valve doesn't need to be mounted to the hull or a wall - the Y-valve is fixed well in place even though that place is not attached to anything except hose.

Also notice that the hose leading to the holding tank is short and self-draining, and that the one from the valve to the ocean heads slightly down.  When working on boat projects its useful to develop a different aesthetic than normal - I look at the picture above and think: That's Beautiful!

The last thing I could point out, if you ever plan to do this yourself, note the routing of the hose up to the vented loop - it was originally in front of the valve-holding tank hose and after staring at it for a moment I decided I didn't like it there and ripped it out, bought five more feet of hose and re-routed it.  I did this to give more space for storage.

The valve I'm using is a Bosworth BM95 Sea-lect Y-Valve.  It's much beefier than my old valve.  The handle is made of epoxy coated aluminum.  This new handle is not going to break off in my hand like the old one did.

Every now and then someone asks me what I learned Out There cruising for a year and I kind of shrug my shoulders and say 'this and that' not really knowing how to answer the question.  Here's something I learned!  When its possible to make your boat more maintainable, do so.  My choice to make the vented loop more maintainable added cost, possibly made my head uglier and made the project more difficult.  But I'm glad I did it.  Having a working vented loop is important and my previous setup wasn't maintainable.

One of these days I'll get back to sailing, but not just yet.  More to do.  If this concerns you, don't let it, I'm having fun in Seattle but at the same time looking forward to taking off again next summer.

[Ok, at the start of this post I said that I write these up as a record keeping exercise.  Clearly, once I get started I just can't shut up!]