BIG problem: Blocked deck drainage pipes....

[McSalty]

Here I am with another problem that is literally causing me some sleepless nights....

1.: Situation
My boat (steel) is equiped with 6 drainage pipes (steel, 3 on each side) that lead from the deck to just above the waterline.

The boat has been lying alongside a jetty that is being populated each weekend by literally up to 35.000 (!) "kids" excercising "battle-drinking".

For some reason they think my boat makes a better wastebasket than those provided by the city and throw (to smash) empty bottles (and bubble gum and anything else they want to discard) on the boat.

The boat has been neglected for some 3 years - and you would not believe the amount of glass of any size that I have removed from the deck since buying her.

But:

2.: Problem 1
Some of that glass, + bubble gum + "natural environmental dirt" + flakes of old varnish have washed into these drainage pipes, clogging them up effectively.

The pipes - for some reason unknown to me - are only of approx 1" diameter (even so there would have been plenty of room for twice that size!).

I have tried poking through the blokage with some strong steel-rods: invane.

I have tried to wash it out with a hose from top or bottom: invane

I managed that the water does "trickle out" again, but am far away from "free flow".

So I now baught a special tube-cleaner for my pressure washer and will try that out today. Wish me luck! .... If that does not work, I really am out of ideas.

3.: Problem 2

The pipes being steel, having been sitting with water standing in them for a while, it is no surprise that they have started rosting.

This not only makes for ugly brown streaks flowing down from the bottom hole, but obviously includes the danger that eventually they will rost through, spilling water INTO the boat.

So I am also looking for a possibility / idea how to get a decent amount of rost converter into these pipes (after freeing them of the blockage) to stop the rosting ... and ... how to best follow this with some possibiity to apply protective paint to all of the pipe's inside!

Any ideas?!

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Problem is, that I can not access these pipes from the inside. There is lots of interior built which I would have to rip out first (naturally: I do NOT want to go that road!)

I am also not sure if it would be possible to weld new pipes as replacement (twice the diameter) from the "outside" without setting the insulation and furniture on fire (?!) ... But, even if that would be possible, it's not an option because for some reasons we will not be able to drydock her until next spring. So I have to find a solution that lasts at least one year.

Am grateful for any and all tips and advice!

 

[yoda]

McSalty

Not an easy one but if possible try to unblock from the bottom upwards, puoshing the debris back out the way it came in. You can expect the blockage to be where there are bends which from the description sounds like it would be near the exit from the hull. As for cleaning out the pipes and then stopping rust you could try a round wire brush on a long flexible drive from a drill to clean off the worst of the rust and then plug the exit to apply some rust convertor. You may still need to try and paint inside the pipes and my only idea for that is to use something like smooth hammerite. Perhaps the same method of blocking and filling the tube with paint, leave for 20 minutes and drain off (so you can re-use the bulk of the paint) may give you a coating that will last a year. Getting it dry I guess shouldn't be an issue but the more loose rust you can get off with some form of wire brush the better.

In the end the only way to deal with it is to fit a non-ferrous pipe to replace the current ones.

Yoda

 

[NOHOH]

..and in the meantime.....

...make something like the little devices used in the UK to stop leaves blocking up the drains...or even those things you put in the plug hole of your kitchen sink to keep out vegetable peelings etc.

 

[sarabande]

compressed air from low down, upward, and eye protection.

 

[Deleted member 36384]

DynoRod, Air and Fill With Paint

Engage the services of DynoRod or some such drain company. They will have the pressure and tools for unblocking these drains, in small sizes as well. Further, the process will strip the inside of the pipes of loose scale and rust.

I would then blow air through them to dry the insides, insert a bung in the end, fill the holes with a suitable paint and then remove the bung and let the excess paint dry off.

If you can access the pipes with a small roller brush, end on, then that could be an alternative to the bung and fill method.

I understand that there are products available for sealing the inside of old tanks by filling and draining, so using such a product may be your best bet.

On Rival yachts, they have GRP deck drains, similar to your steel pipes, they fill them with Epoxy and drain off the excess to affect repair.

 

[prv]

Could you paint it by pulling some kind of furry thing through on a string, soaked with paint? I was imagining a small piece of carpet, rolled up with the furry side outside, although that might be too big for your pipes. But anyway, a furry wad dunked in paint and pulled through.

Pete

 

[Lakesailor]

The Dyno Rod suggestion gets nearest to the answer you need. (I used to run a Dyno Rod branch for the company) Whether Spain has Dyno Rod I don't know. A Quick Google produced this result.
There are two approaches that may work. High pressure water getting from below using a small jet head with a forward facing jet (I don't suppose the one you have has that) The flow and velocity of a commercial jetting pump will be far greater than that provided by your pressure washer (don't confuse pressure (psi) with water velocity and flow, a combination of which is needed to clear your blockage. You may find your drain kit for you washer does the job, in which case you've saved a bit of cash.
The other method will still need a drain specialist using a flexible drive to cut into to blockage. These machines are pretty powerful.

Smaller one for domestic use looking a bit like a large hand-drill may possibly not have the torque to cut or dislodge your blockage. It depends entirely how jammed the material has become.

Local plumbers may have these machines.

If a high pressure jetter is needed try firms which specialise in industrial jetting of boiler tubes or chemical plant.

Dyno Rod has a reputation for being a bit expensive. A local independent would probably be cheaper, but if it clears the problem a few quid on someone with the right gear is worthwhile.

 

[Deleted member 36384]

... On Rival yachts, they have GRP deck drains, similar to your steel pipes, they fill them with Epoxy and drain off the excess to affect repair.

Further to my last post there is an alternative. Some Rival owners have just sealed up their drains, top and bottom and made normal scuppers through the gunwale by drilling and inserting a small length of pipe. If there is any doubt about the integrity of the inner pipes, this may be a better solution.

 

[Searush]

An add-on to Old Boots' excellent suggestion is to add flaps to the outside of the new pipe drains if there is a risk of water coming into the cockpit.

 

[nimbusgb]

Can you get to the pipes inside the boat? cut them off at the top and bottom and replace with synthetic hose of some sort.

Or seale them up and install scuppers as someone else suggested.

 

[Bilgediver]

The pipes - for some reason unknown to me - are only of approx 1" diameter (even so there would have been plenty of room for twice that size!).

I have tried poking through the blokage with some strong steel-rods: invane.

I have tried to wash it out with a hose from top or bottom: invane

I managed that the water does "trickle out" again, but am far away from "free flow".


Any ideas?!

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I think one method you could consider is the same as oil drillers use to clear out an oil well.

Make a tool from steel pipe which will just fit inside your pipe and make the bottom end serrated like a cutting edge. The length depends on how straight your pipe is. connect a rod to the top say 10mm dia and then use this to core/drill over the rubbish so the rubbish goes inside. If you are lucky this may work especially if you also put water pressure on the outlet holes near the water line.

WHen you get the pipes clear you can prepare for painting by using a small wire brush or emery flapper wheel on a long rod powered by drill. This will be cheaper than the specialist boiler tube company

Painting as others have said by making a ball of cloth on the end of a stick and pouring paint on it from above as moving up and down. Catching surplus paint at the outlet.

The 90 degree bend with have to be dealt with from boat side as well as above... If there is likelyhood of glass then wear goggles and gloves!!!

 

[pappaecho]

cleaning up dull fibreglass

My new old oat came with a two handled mains polisher unit and lambswool bonnets for polishing. However I want initially to cut back the oxidised gelcoat with T Cut or Farecla. What sort of bonnet do I use for cutting back?

 

[McSalty]

Thanks for the excellent advice and ideas to you all!
(Well except for the last posting, which I maybe just did not understand?)

Anyway, here is an update of the situation:
SUCCESS!


Turned out that these drainage pipes really ARE a "mis-construction" since they do go straight down from the deck just to end in what seems to be a regular "L-shaped" plumbers piece for the through-hull above the waterline.
The radius of that "L" is so narrow, that no hose will fit through.
But digging in from the dinghy with a screw-driver it was possible to remove lots of glass, varnish-flakes, plastic-ice-cream-sticks, chewing-gum (yaiki!) etc. to eventually free all 6 drains.

The remainder of the job did that special pipe-cleaning-extension I bought for my Kärcher (Karcher / Kaercher?) but even that did not manage to "navigate" the bend.

But, most importantly the drains now are free, and I will just keep flushing them regularily while alongside this dock to keep them that way.

Part 2:
Particularily grateful I am for the idea with blocking the "exits" and filling the pipes with rost-converter, draining it off after a while (anyone any suggestion on how long to leave that "liquid" in there?) and repeating the process with paint.... carefully making sure that no water will flow through these drains until the paint has dried. The humidity rising from the sea hopefully will have no adverse effects on the drying-time.

Next occasion I'll have while on the dry (next year, the soonest) I'll try to somehow gain access to these pipes from the inside, remove the straight-piece + L-shaped "knie" and replace them with (a) larger diameter pipes and (b) pipes that will run completely straight (which means that they need to be cut in an angle as well where they meet the deck as where they end at the hull. I hope that this will put an end to the drainage-pipe-problem for ever!

Once again: Thanks for the great advice and many thoughtful expert-postings I did receive!

 

[Bilgediver]

T
Part 2:
Particularily grateful I am for the idea with blocking the "exits" and filling the pipes with rost-converter, draining it off after a while (anyone any suggestion on how long to leave that "liquid" in there?) and repeating the process with paint.... carefully making sure that no water will flow through these drains until the paint has dried. The humidity rising from the sea hopefully will have no adverse effects on the drying-time.

I think it will help if you can find a wire brush for an electric drill which will go down these pipes. Fit it to an extension rod and use it to mechanically remove scale in the pipes before the rust converter is used.