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2012-03-29

The invisible revealed

This is what happens, I guess, when artistic meets statistics.

I could watch it all day.

UPDATE: I've been in e-mail contact with Fernanda Viégas and Martin Wattenberg, the designers of this wind map, and while they are concerned (fairly naturally, I think) about the kind of bandwidth charges peering at this sort of graphical representation this could cost, they are considering making it more accessible (i.e. embeddable) for more general use.

So I'll stand by and await results. If nothing else, it's very beautiful. The developers in question have several very intriguing ways of presenting statistic in memorable, aesthetically pleasing fashions.

2012-03-28

State of heads

It's called a "Popular". In southern climes, a sobriquet no doubt absolutely truthful

I have an older, if very lightly used, Lavac head on Alchemy. By "older", I mean it was installed by a previous owner, and so went in prior to 2006. But by "lightly used", I mean "hardly sullied as per its bailiwick". The boat's not travelled very far without access to shoreside facilities, and naturally, I encourage that over the indiscriminate filling of the 50-gallon holding tank, which I usually am deemed worthy to empty.

Indeed, without getting overly graphic, I discovered a flaw in said tank only after we reached the one-third full mark and, well, you can visualize the rest. Hauling a stinky HDPE tank out of the boat is what convinced me, among other considerations, to opt for four 50 gallon water tanks, instead of two 100 gallon tanks. I can just about manage shifting one, whereas I need mechanical aid to budge the other.

But I can't fault the Lavac in that now long-past unpleasantness. As I've mentioned before, it was the presence of a pristine Lavac, the boat bog what ate jeans without gagging...a somewhat curious selling point, in my view...was the deciding factor for my wife in the purchase of Alchemy, so sterling is its reputation as the top shelf of seagoing heads.

The feeding of the typical cruising boat head is obvious, even if visitors keep screwing it up requiring orientation seminars on deck. The rule of thumb (rule of bum?) is to not put anything it there save toilet paper and what has passed through, or at least has lingered, in the body. The plumbing of the typical head, while robust, is only a fraction of the diameter of the average home's "waste pipe", and feminine sanitation products, cigar butts and small plastic toys will cause extremely unpleasant aneurysms of sewage and a very upset skipper or other designated boat slave.

The care is less clear. Obviously, one brings rebuild kits for the various parts and, equally obviously, they are not cheap. But while one can, with a little practice, make a decent low-pressure gasket by hand out of a sheet of cork or even a cereal packet, certain items require The Approved Replacement Parts.

A Lavac, being the vault of Malkuth, falls under that heading. Yes, another sea toilet pun.

Amusingly, this is titled as "Exploded Diagram". I blame Taco Night.

The Lavac is available in manual and electrical pump version, but I am of the opinion that electricity and toilets should have no more proximity than bankers and financial reform regulation, and that to believe differently is to exhibit insufficient superstitious dread suitable for cruising. Besides, the heart of the matter, the "Henderson Mk. V Pump", is easily understood, more or less modular, and the pumping action allows measured application should you wish to do various remedial freshwater rinses. Besides, a simple diverter valve means that a) the same pump can be used to pump out the holding tank overboard in the legal areas of the sea, and b) a similar valve can be used to empty the bilges or, more typically, a shower sump inside the head. I suppose c) would be "exercise", but if you are pumping the Lavac enough to build your biceps, you may have issues beyond the device's stated functions.
This is actually, if not a pleasure to work on, a straightforward thing to service

Now, we aren't even in fresh water currently, and so the Lavac is in hibernation via the magic of "winterization", but we are fitting out for extended ocean travel after extended freshwater travel to get there. This brings us to the "care" side of "care and feeding". I am considering purchasing an entirely new pump, gaskets, lid, etc. (the Lavac works on a sort of vacuum pump principle, and the lid seals shut during the pumping process), and taking the aged but sound parts as spares, cleaned off as required and bagged, of course. This is the same principle as getting a new diesel (if about 1% the price): Replace good parts with new parts, reset the odometer in theory, and reuse the older parts as spares.

Due to the rubber/nitrile seals and the innards of the pump, which in some cases contain aluminum bits, I have heard that these otherwise excellent units can suffer from over-aggressive cleaning with the sort of cleansers and solvents once resorts to in order to clear out, uh, tenacious leavings and to kill the nearly inevitable lifeforms brought in from the seawater used to transport the human elements.

Many, therefore, use vinegar. But vinegar is expensive and bulky, and it's not really necessary. The portion you want is the particular acid that gives vinegar its kick: acetic acid. You can buy acetic acid (which is only about 5% by volume of typical white food-grade vinegar) at near 100% concentration and can dilute it yourself for economy, but if you can collect and tank rainwater, a good method for Lavacs is to (carefully) plumb in a Y-valve to your seawater intake line and to give the whole system a freshwater rinse. This will kill the "critters" that may otherwise colonize the more attractive bits of real estate and will, with the acid treatment, move the debris back to its mother, the sea.

I'm no expert on this, even with the wealth, so to speak, of resources out there on the topic of "marine sanitation",  but years and years of reading Peggie Hall's posts and articles have convinced me she is indeed worthy of the title "Head Mistress". So aside from hearing from the readership as to what works, what helps to avoid trouble, and what is definitely to be avoid unless one has very particular enthusiasms for living in filth, I would encourage the curious to read her "bible of boat bogs".

Dense, green cartoonish vapours suggest you've let things ride too long.

I have the feeling, much like The Warm, Dry Boat, and the fixit guides of Nigel Calder, this book will be a well-thumbed volume in the ship's library. Perhaps even read in a sitting position.

UPDATE (March 28/12): Regular reader, current cruiser, fellow Torontonian and Lavac-owner Geoff C. on s/v Beach House sent me his thoughts on Lavac installation, complete with photos (!), and has given me permission to quote him here.

Our previous boat had a Lavac head which is why I installed a one on Beach House. It is a bullet proof unit so long as the seat seals and connections keep the air out.
Recently I did a pump overhaul because it had been at least a year since the last one and it was getting hard to pump.
The joker valve was a little puckered and because the output has to point up, there was old "debris" caught around the outside of the valve thus limiting it's opening and restricting the output flow. I've decided that the output hose will be removed more frequently so that expansion of the joker valve can be checked.
After this rebuild, and a few days later, we could hear a hissing and the bowl wasn't filling properly. The seat seals were removed, cleaned and reinstalled. The issue remained. On taking the pump apart, I found that the joker valve was dislodged at the top. It seems that the longer screws in the kit aren't quite long enough and didn't bight into the valve enough to hold it.
Naturally I didn't have screws that would work in my box of fasteners, so off to Budget Marine. We are now waiting to see if this fix holds.
One other issue we have is access to the lower pump (input) connection. There is not quite enough space for me to get both hands in to force the hose off nor is there enough space to bend the hose to meet the input connection.
My solution was to create a bend using household plastic plumbing parts. 90 and 45 degree bends did the trick. Sealand makes 1.5" sanitation hose to plastic pipe adapters. I bought mine from Eastern Marine and I found the Union in a hardware store in Antigua. So now my input connection is quickly disconnected by unscrewing the collar which clamps the two halves of the union together. No more undoing clamps and messing about with forcing hoses on and off.
Photos -
Lavac - Union = stand alone part
Lavac - Union from top
Lavac - Union from below.




I don't know how your pump is installed, but if access is an issue this might help. 


To which I replied:  Geoff, thanks for the e-mail. I like your solution even though I have a fully accessible Henderson pump with easy access. That's not to say there aren't other places well hidden where I might want to lob in a diverter.

So the timeliness of your e-mail relates to understanding how the various parts need to work properly to make that vacuum, without which "she no workee".

Now that I know how you keep the joker valve functional, may I ask how you keep the passages free from sea salt deposits and the local wildlife? How do you manage offshore pump outs? Do you ever get air vent or anti-siphon vent clogs? Having had issues with exhausts on both boats, I will go to some lengths and even dip into the rum fund to make the setup as bulletproof as can be reasonably expected. I'm not shy of the muckiness (well, not keen, either), but I feel that a proper design from the outset gives peace of mind and reliability, rather than trying to fight the physics of the thing with the application of more force.

Glad to find another Lavac fan.

And to which Geoff replied: No problem with you using it.

We don't have a screen on the input water so occasionally we get a little debris, but since the input sea cock is about 3 feet down very little. So far no wild life other than a little phosphorescence which is quite pretty and makes a midnight visit worthwhile.

Our sanitation hoses were new in 2005 and hit salt water in 2008. They aren't bad but there is no way around build up on the walls. I think it is a bigger issue when boats are stored and the coatings get really dry and hard. The longest we've stored Beach House is a month and all seems well. We're into four years without any appreciable issue. If you have concerns think about using a good but not expensive hose and replacing periodically. In 2005 I installed good hose but as I modify things I'm using a lesser hose. To anyone headed (no pun intended) south I always suggest replacing the sanitation hoses while they have the time before they leave.

Pump out facilities generally hard to find down here so most boats just go from the head to the sea. A few  will up anchor and drive out to sea and dump their 50 gallons of waste, complete with anti smell chemicals etc, until they get tired of the routine of the weather closes in.

So far no clogs, but then we pump a lot of water through with each flush. We determined how much flushing to do buy putting some toilet paper in the head and counting the pumps until I saw bits of paper beside the boat. The problem with holding tanks is that you are conscious of the amount of flushing water you use and skimp. Skimping may mean you leave solids in the line.

A good working head means a happy Admiral. A happy Admiral means a happy Captain.


I can only heartily agree, and thanks, Geoff, for both your observations and your excellent explanatory photos.

I do agree that whether one thinks it a sign of irreversible Western decadence or not, we have become to expect toilet facilities of a certain standard of reliability and function, and people will endure hard bunks, bad cooking and twisting seas as long as the toilet is working properly. Geoff's point about redoing the hoses completely more often (as opposed to getting the super-duper "sani-no-smell wonder hose" is also taken, as are the comments about the relative rarity of North American-style pump-out stations.

As for "skimping" on flush water, heaven forfend. I suppose if I was looking for a reason to keep the 50 gallon holding tank, there it is. The threat of leaving "solids in the line" is why I avoid butter; if more water means less clog, we'll all have very strong wrists and diluted pumpout.

And as for getting tired of the routine of going to sea to pump out, we'll see. Inculcated as I am (and my wife even more so) in the idea of treading lightly on the sea bed, to mangle a metaphor, I do not wish to be part of the reason brown trout outnumber tropical fish in any distant anchorage if I can avoid it. And while I'm not squeamish about the topic, I feel my cruising experience might be a little sullied by sipping my morning coffee to the sight, sound and smell of a number of nearby boats at anchor ejecting poo rockets from their topsides into waters I want to row through after breakfast. It just seems a little off-putting. Yes, I know fish crap in the ocean...whales, even. I also know that the sewage treatment for the locals is going to range from straight into the ocean to rudimentary at best. That doesn't mean we as cruisers have to pump raw inshore when we have other options. My vote goes to as-needed six-mile round trips. At least the engine gets oil circulated and I won't object to turning the fridge up to make ice cubes. Which will, inevitably, lead to more use of the head.

Simba, descale me!