Chain locker drain, through hull.

fredrussell said:
I share the OP's dislike of drilling holes in my boat. I would use the first variety and just stick them on with sikaflex/ct1/etc. They would stay on there I reckon.
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Locker won’t drain very well if you aren’t prepared to drill a pretty decent hole ! The fixing screws are tiny by comparison
 
When fixing the type 1 covers, you drill small holes for the screws, just deep enough for the self tapping screws. if you like, you can put a bit of sealant into each hole before fitting the screw, which will prevent water getting between the screw and the hull. However, as you don’t need to drill all the way through the hull and it’s going to be wet on both sides, I wouldn’t bother with any sealant in this instance. The idea of putting sealant into screw holes is to prevent water getting inside the hull which is redundant here.
We have the type one covers fitted on our anchor locker drain holes, which are about 10mm diameter. Never had any sort of problem with then other than the inevitable grot on the hull from dirty water draining out of them.
 
Crazy-Diamond said:
Here are some pics of my homemade chain scrubber/cleaner in action (more pics below). Before starting to raise the chain (I have an electric windlass) the device is attached and run down to just below the water level. As the chain is raised I run it up and down, and can see the mud running off in the water. Because I like to keep everything as clean and dry as possible, I tend to pause when raising to allow water to run back down the chain before it comes over the roller. I also position a rag under the chain before the windlass to collect the odd drip.

1583757358801.png



1583757383143.png



This is the scrubbing end (next to a boat hook). There are two domestic gutter downpipe fittings screwed through the pole, each one with a small amount of the circumference cut out, and astro turf matting sikaflexed in place.

1583757392087.png




As you can see, the holes in these are opposing, which stops the chain popping out. Clipping the device on and off is not difficult. There is also a mini brush, designed to help getting mud off the anchor, this has proved less successful, and I may remove it as I am worried it will damage something!

1583757399759.png




The Essex mud is deep and thick. Previous experiences were of significant amounts of mud on deck, and in the chain locker, making for a dirty boat. Since using this I have almost completely eliminated the mud - there just isn't any. I actually thought I must have been anchoring in gravel when first using this, but the Crouch and Roach are mud, and the anchor had plenty of mud too. It just works, and is super simple, much more simple than my original plan of fitting a pump.
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Your chain cleaning regime is brilliant and the chain cleaning device effective. I think you posted about it a few months ago - I liked it then, I like it now.

It is inevitable that the chain will enter the locker wet, not necessarily sodden, and the water is salt. Salt simply accelerates corrosion. I advocate good drainage in the locker, hence the perforated locker base to encourage airflow but also wash the chain with fresh water (rain if that's all you have) to get rid of the salt (so open the locker to the rain if you are on your swing mooring and then close the hatch/lid before you leave. Clean, well galvanised chain will not hold nor absorb water and if there is a decent airflow, lift the lid/hatch slightly when you are at home - the chain will dry.

Keep the water, mud and salt away and you will prolong the life of the chain. Take all the chain out and wash both chain and locker. Simple really.

You know when you have anchored in anaerobic muds, apart from the smell the chain turns black.

The first few links, maybe 2 or 3, of the rode, those attached to the anchor shackle will preferentially corrode - I assume because there are different alloys of steel (chain, shackle and shank). These corroded links will need cut off every so often.


Going back to the OP - I've never liked the idea of the chain draining to the bilges - no wonder bilges smell.

I'm not an expert on drainage holes - but I'd think a bigger drain hole, one on each side even better, rather than smaller. So 15mm rather than 10mm. As suggested gel coat the edge of the hole you drill, and drill it draining from the inside, aft and down. I'd attach the clam shell vent with Sika and use small self tappers, small so that they do not pass right through the hull. Seal the screw holes with more Sika.

Jonathan
 
Thank you all for the responses. I can certainly see that the cast through hull may not be as long lasting as the stainless shell cover. ASAP has some that are chrome plated brass:

1588147685853.png

Which are more expensive, but will not break the bank. Is that even better at resisting corrosion and decay?

As much as I dislike the idea of drilling small holes for the self tappers, I actually find the idea of drilling three holes all the way through the hull, and using 316 bolts to hold the shell on. After all, this is just a smaller version of the way the hull anode is held in place, which is always under water. If I use decent quality bolts, and ensure the holes are filled with sika when assembling, along with a healthy covering inside, is that worse than the self tappers? I I just don't like the idea of having the threads of the screws digging into the GRP / gelcoat. Mind you, there would be the nuts in the chain locker, which might get damaged by the chain. Hmmm..............
 
You’re in danger of overthinking what is really a very simple thing! The covers are very light and designed to stop water surging into the locker through the drain holes. They are therefore not subjected to any significant loads at all, so three small self tappers will provide more than enough strength to fix them in place. Drilling all through the hull to use nuts and bolts will mean you need to get down to the bottom if the locker to put the nuts on and tighten them as well as needing someone on the outside to use a screwdriver.
As to materiel, I stick to stainless as using chromed brass with stainless fixings risks dissimilar metal corrosion.
 
Crazy-Diamond said:
Using the covers, do you have self tappers into the hull? Are they sealed from the outside? With something painted over the top of the screws?
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I used s/s self tapers to hold the covers in place bedded in with butyl sealant. The hull is single skin so no core to worry about. Nuts and bolts possibly a bit to much in my view.
 
Crazy-Diamond said:
Hello all,

I'm going to fit a drain to my chain locker, rather than it draining to the bilge. I could use one of these:



View attachment 89305

But I don't like the idea of drilling the holes to secure it.

Any reason not to use one of these:



View attachment 89304
Click to expand...
Am I missing something?
You have to drill the big hole for the drain in both cases. The only difference is an extra 3 small ones. What exactly are you worried about in drilling the 3 extra holes? The second item is normanlly used as an overflow or vent on a tank, not normally as a drain.
 
You cannot in fact use nuts and bolts in this application, unless the locker design is unusual.

Ideally you want the drain to be at the lowest point in the locker and angled slightly down. This way the locker will completely drain. Again ideally - you want to aim to have the hole just 'cutting' the locker base - but this might be difficult. If you can drill a small pilot hole from inside and then drill the main drain hole from outside it will be easier (I think someone made this suggestion earlier)

When you come to attach the cam shell vent the lowest attachment point will be below the hole you drilled and it will possibly be a solid bit of hull - with no space inside. So the lowest attachment point maybe opposite the locker base (so you would be drilling into the base) or it will be into the 'end' of the vertical bulkhead. If the lowest attachment point is as I envisage (though may not describe adequately) this may mean you can use a longer self tapper - making the vent very secure (as you will use Sika as well?).

Only you know what the arrangement is in the lowest corner of the locker - I'm just guessing.

Jonathan
 
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