LM27 sump/keel drain plug

[Sula]

On the side of the bottom of the keel on my LM27 is a bronze(?) fitting.  This was described by the surveyor as a 'sump drain plug'.   I am guessing that this allows the bilge to be completely drained of water for those cold Scandinavian winters.  Is that correct?

Does the plug simply unscrew?  And is there any particular mechanism to secure it/prevent it from unscrewing?

[Charles]

Not sure where on the keel this plug is. On Marguerite more or less under the driver's seat is the bronze(?) transducer for the old - and useless - electronic log; could it be that?

And when we were buying her the surveyor found high levels of moisture in the hull on the starboard side about two feet in front of the propeller. Once the antifouling had been stripped off it was found that there was a fibreglass plug sealing a circular aperture about 30 mm across. The plug itself was cracked and that was the source of the leak, easily solved by grinding out the plug and its surrounds and then renewing the fibreglass in the area; no problem since. The perceived wisdom of those present was that the aperture was probably a manufacturing device to enable LM to handle the slippery hull when it came out of the mold and that the plug was then used to seal it later. It certainly didn't give access to the bilge and owners had clearly never been meant to know of its existence. Perhaps your bronze plug is a smarter version of our 1981 fibreglass one.

Don't know if this helps.

Charles

[duckie]

Mar 30, 2017 23:20:42 GMT Sula said:

On the side of the bottom of the keel on my LM27 is a bronze(?) fitting.  This was described by the surveyor as a 'sump drain plug'.   I am guessing that this allows the bilge to be completely drained of water for those cold Scandinavian winters.  Is that correct?

Does the plug simply unscrew?  And is there any particular mechanism to secure it/prevent it from unscrewing?

Hi,

it is correct that it is a sump drain plug - You just use an ordinary (but large) screwdriver to screw it out. I believe that most owners who have done this will use locktite or similar when refitting the plug. On my LM27 it took some time to find the plug underneath many paintlayers - but when found, it only took a few minutes to unscrew it, check and refitting with mild locktite. No problems at all.

Yours

Duckie

Danish LM27 owner

[oceandancer]

Hi Sula,

The plug has a very fine thread and is made of bronze so don't lose it as it would be difficult to replace! You will find that even with the plug removed there will still be about 2-3 in of water in the sump. You can drain most of this by using a length of 10mm plastic tube as a syphon. Suck the water up the tube a little and then quickly hold it below the keel level. You may want to weight the tube down to the bottom of the sump by using an appropriate steel nut which the tube just screws into. You can find the exit hole from inside once the plug has been removed as long as you can reach all the way down.

Alternatively you could use a wet and dry vacuum cleaner. You will find that there are all sorts of things down there, screws,washers, plastic etc

I use ordinary mastic to seal the plug as the thread is very fine. A coat of antifoul over the top and that's it.

Regards

Mick

[Sula]

Thanks, all of you. Most helpful. Now I'm clear about what I'm looking at.

For Charle's benefit, mine is on the port-hand side, from memory about 8 inches (150mm) up from the bottom of the keel, and five feet (1.5m) forward of the back of the keel. It's a small circular bronze fitting, about, say, 1 1/4" (30mm) diameter. Looks like a small water inlet/outlet skin fitting, but instead of a hole in the middle it has a slotted head, sunk a few mm below the outer part of the fitting. (I tried to take a photo today, but my phone was being uncooperative.)

[Charles]

Many thanks. I'll look for it when I next see the boat, but that will be on 11th April and she will be in slings at the boatyard, ready for launching, weather permitting, so I won't be able to investigate until next winter. I'm not aware of any ill consequences from my never having drained the bilges.

Charles