A morning of ‘wishing I’d thought about that a bit earlier’:
Having been disturbed from my book by Lesley’s call that: ‘The head’s pump has jammed solid’ – she was the one using it, so why is that my problem? – I happily laid my book aside for the joyous alternative of playing around with some pressurised turds.
As a recent convert to the idea of illuminating such tasks with a torch that ‘fits comfortably into your mouth’ rather than head-torches (thanks Tony Goode off ‘S/Y Capische’) I’d inserted/removed said torch at least half-dozen times before getting around to contemplating what my hands were doing in between.
Having discovered that the three-way valves and 38mm outlet hose had scaled-up to perhaps 12mm diameter, Lesley pointed out that it was ‘better to discover that now rather than half way to Tonga’. I immediately recalled Lesley having said almost precisely the same thing with regard to these hoses and our passage to the Marquesas; that had been back in Panama over a year ago, no wonder they were chocked-solid!
Having stripped out all the hoses, vigorously beaten them over the side to clear out the calcite deposits and begun the reassembly process, I recalled that on all previous occasions that I’ve pulled the long hose to the outlet seacock out from beneath the floor, I’ve first taped a draw-cord/mousing-line onto the end of it. I now know that you can re-thread it without one, provided of course that you fancy an extra hour or so of wallowing around in sewage.
Having eventually got all re-assembled, working perfectly and with no leaking valves/pumps/joints (first try - a miracle!) I was at that point that anyone whose done the job themselves will appreciate; that wonderful moment when you can leap over the side and freshen-up, before re-boarding to take a very soapy shower. That was exactly the moment when I recalled what the surgical nurse at Raiatea hospital had told me just yesterday about my leg wound: ‘You can shower as normal, but don't risk infection by going into the sea until the stitches have dissolved in 3-4 weeks’ time”.
Perhaps I should just be grateful that the nurse hadn’t put any prohibition on fixing the heads, or suggested that there might be any infection risk from playing around in raw sewage?
Bob, we got a top tip from a very experience round the world OCC sailing couple when we were in the Med. There's something about the seawater in the Med that seems to scale up the pipes in superquick time and, as always with yachts, the after dinner conversation migrated to maintenace challenges. Their top tip was to regulalry descale the heads pipework with ordinary vinegar. We did a quick schoolboy calculation on the volume of our outflow pipe and initially just pumped that amount of vinegar through and then shut off the outlet valve. We left that overnight or even for 24 hrs. It's been amazing; we haven't removed or banged a 38mm outlet hose in 5 years. Our latest improvement to the procedure is to pump like billyho to fill the outlet pipe with air and, as a double act, as the last pump is made the skin fitting valve is closed. We the loosen the air bleed valve on the top of the swan neck and GENTLY pump in the vinegar though the bowl until the pipes are full and small amount bleeds out onto a tissue. With this method the vinegar now completely fills the pipe on both sides of the swan neck including covering our selector valve to the holding tank. That now turns easily always which it didn't always with the old method. As a final addition, Nicky did a calculation on how many pumps it takes to completely flush our long outflow pipe run (28 pumps!!!) and since we then have been pumping that much per flush (when pumping to sea) and have noticed an improvement in slower scaling up. Hope our suggestions prevent a rerun of your recent trauma.
I had a blockage (the heads that is 🤣) crossing outer biscay from Ireland last summer. After spending sometime upside down and contorted in the heads areas, a yachtmans handbook in one hand and a variety of implements in the other (including a wire coat hanger and various parts of the heads), we decided that the blockage was external. One of my crew, an experienced diver, donned the snorkel and mask, armed himself with the coat hanger, and within minutes the blockage was freed!! Too much loo role....no blame apportioned, but I may have been the last user! However, the material that came out was calcified too. Since then we use a sealed plastic bag, and contents disgarded at an appropriate land bin. Now nothing goes overboard, only the fishing line 😇😎
We periodically flush hydrochloride acid ( aka muriatic acid) through, leaving it in the system overnight
Seems to avoid scale
It is sold for cleaning concrete and other stuff, but is hard to find in some countries
---------Linda Lane Thornton
I bought some of that when we were in the US, Neil McCubbin, but the instructions and the warnings were dire - so I went back to vinegar instead.
Agreed that care is required. It is used a lot in industry, and is much more aggressive to head scale than vinegar.
Neil McCubbinI I agree re the muriatic acid. IT takes a long time for household vinegar to work. HCl does not seem to bother plastic or synthetic rubber very much. The 30% or so vinegar sold in Denmark, in with cleaning products, will bubble away a lot too.
I have not found vinegar very effective - maybe not using enough often enough - but agree re Muriatic acid but what % dilution/concentration do you use? Recently had to clear all the hose in both heads. Norma watched but reported that I was "heroic" - that made it all worthwhile....
The real solution is to prevent the pipework scaling up rather than trying to remove the scale. Scale is formed by the reaction between urine and seawater, so flush the heads very thoroughly after each use to ensure complete removal of urine from the pipework. Most heads manufacturers quote the number of pumps to clear each metre of pipe. Aboard Al Shaheen we pumped 20 times and never had a scaling problem in 15 years.
John Franklin We do same, but cannot when marinas or small anchorages for longer than the one day or so that our holding tank is good for when pumping a lot