Galley sink drain

Ever since the purchase of my trusty Southerly 135, I have had an irritation with a fickle galley sink drain. Sometimes it runs away with alacrity and yet, sometimes the dishwater just sits there, seemingly forever. The problem has defied cleaning bleach and the handy plunger but it has never been at the top of the ‘to do list’ so it has, until now, evaded my focus.

So, I began to think the problem through. The sink drain outlet is just below the waterline and there is a twin sink feeding it with large diameter (typical domestic size) waste pipework. I remembered how I fixed a problem with the AC condensate drain which turned out to be an airlock and eventually fixed by drilling a small hole in the top of the drain pipe run. There are water filled traps so; there is the potential for an air lock between the traps and the underwater outlet when upright or on port tack preventing the drain from flowing. How do you check the theory? I made the decision to drill a hole in the top of the pipework just below the traps into the hard plastic elbow to vent any airlock – if it didn’t work I could always fill it with silicone so no real harm done. The drilling was something of a challenge as the pipework is recessed and there is little room, it needed a right angle chuck and a shortened drill bit.

5mm tap and irrigation spigot

It worked, the sink ran away just like that !

The challenge was then, how to retain the breathing hole yet not suffer a leak when heeled.

Spigot screwed into the tapped hole.

The answer was simple. I remembered that I had some domestic irrigation pipe tap off spigots which screw into the soft pipework making their own hole. This I tried to ‘self-tap’ into the hard pipework without success so I had to adapt a thread tap so it could be turned in the confined space.

Irrigation pipework pushed over the spigot and extended to inboard of the sink under the worktop.

This accomplished, I screwed the spigot in, I attached the small bore rubber irrigation pipework and extended it ‘uphill’ to the inboard side of the sink so it would not leak when healed. A very simple solution to an irritating problem.

Tools for the job. Right angle chuck, shortened 4mm drill bit, 5mm tap and short turning arrangement, irrigation spigot and pipework.

A similar solution was very successful in relieving an airlock on an AC condensate drain. This problem had been present for a long time and with the drain not running to the bilge where the automatic pump dealt with it, it spilled over the retaining tray and distributed itself around the interior. By simply drilling a hole in the top of the pipe (the pipe would never fill for this to be a problem) the issue was resolved, what a relief !

6 thoughts on “Galley sink drain

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  1. While I’m here, One other drain problem I discovered on our S135 is that when they installed the Calorifier they didn’t put a tube on the expansion valve to direct the water to the bilge. So the outflow water from the cylinder, every time it heated up from cold, has been flowing out onto the landing plate area and right under the keel lift hydraulic cylinder anchor plate,… which they didn’t galvanise. For the last 19 years that plate has been rusting and expanding which is putting huge pressure on the bolts that go through to the keel. Amateurs.
    My advice to all s 135 owners is to check that they don’t have the same situation. It 5 minutes to fit a piece of hose to the relief valve. The relief valve is just below the water pump assembly. Have a check and examine the keel lift anchor.

  2. Sink Drains. Our S135 has a different problem. I note that your sink has an Strap. Our doesn’t and as a result we have developed bad drain breath. I have ot keep the plugs in to avoid a bad smell in the galley. I’ve found some low profile S traps and will be installing one as soon as I can get my hands on it. That is when I will have to do what you have just done as well.
    On tools here in NL we have a spectacular tool company called HBM. Look them up. They have all manner of good quality trade tools at really low prices. One little item I was please to finally get my hands on was a set of stub 2mm to 10mm combination drill/tap/6.35 hex combinations perfect for drilling and threading holes in difficult places with right angle screw heads (Euro 5 each and because they are spiral drills the thread section is spiral fluted too). I’ll send you a photo of the tight spot tool kit I use. Another tool I picked up on a whim is a pop rivet tool that is battery powered drill driven (6.35mm hex drive). I hadn’t had a need to use it but a friend here on the marina was installing a radar post and broke his squeeze riveter and I lent him my powered one. Blown away with the ease of use, drove the 40 klms to HBM where they had one for under Euro 20, he said. Well I paid over Au$200 for mine so next trip to HBM I will be hunting them down. I ‘m expecting it to be awesomely useful the first time I have to install something up the mast.

  3. Nick,

    I only hope the siphon doesn’t work in reverse or it will be gurgle, gurgle, gurgle and an S135 on the ocean floor. You will recall my advice about installing non-return valves!

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