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gillro
gillro

Posted: Wed Feb 09, 2011 9:34am

Post Subject: Bilge draining

Hi there I've just bought a narrow boat and the surveyor has recommended draining the bilge; could you pls recommend how to do this? Thanks Gill

Tony-B
Tony-B

Posted: Wed Feb 09, 2011 10:20am

Post Subject: Bilge draining

I am appalled that a surveyor feels it appropriate to make such a comment without qualifying it. If I replied in the same vein I would just say - pump it out - which is not a lot of help to you. First of all he should have told you how many bilges the boat has. It could be one, two, or three. If the front well deck is above the water line I expect the answer is one or two with the majority of boats having two, but at least one major hire fleet only uses one. Typically the rear bulkhead runs right down to the base plate forming two compartments. An engine bilge at the back and an accommodation bilge under the accommodation. The engine bilge is usually fitted with an electric bilge pump so unless the water around the engine (not under the engine because that is the engine tray) is oily it can be pumped overboard. If is is oily and also for the engine tray I am afraid you will have to sponge or pump it out into containers for responsible disposal and the use degreaser to remove all the oil so you start with a clean bilge/tray. My guess is that he is talking about the accommodation bilge and for that you need to locate or even cut a trap through the floor. It is usually at the back of the accommodation under the rear steps of in the bottom of a cupboard. There really should not be any water down here in most designs but you do get window leaks, condensation and drips from the plumbing causing a build up sometimes. Once you have located or cut the trap pump the water out and sponge dry. Within minutes more water will appear. Do not panic because this is normal as water drains back from around and under the ballast. Just keep sponging until no more water drains back. This could take several days. If you are leaving the boat leave the trap uncovered to get a little air into the bilge. Now I keep saying pump without talking about the pump. You can but manual pumps from chandlers with a handle to pull up and push down or you could buy a drill pump that fits into an electric drill. Any sort of pump will do to get the bulk of the water out. Then I am afraid it is down to sponging. Some people say use disposable nappies for the engine tray and oily bilges but I fear it will be a bit costly for anything but the odd drip. Others say use cat litter. I would advise against this because some will go all muddy and be difficult to get out. Please let me know if you want any more information. Tony Brooks

gillro
gillro

Posted: Wed Feb 09, 2011 10:38pm

Post Subject: Bilge draining

Wow, thank you for your comprehensive response. Am heading to the boat this w/e so will check it out and begin the process. Thanks again, your help is much appreciated. Gill

alanclarke
alanclarke

Posted: Thu Feb 10, 2011 3:31pm

Post Subject: Bilge draining

Hi Gill, one tip i was given was to go to one of the cheaper super markets like Netto or Lidle as they sell bumper packs of babies nappies cheap, cut off the elasticated part away from where the legs fit so they lay flat and lay them in the affected area and leave them for a few minutes this will very quickly mop up that last bit of water thats a pain to get rid of. You just then pick them up and dispose of them and leave you with a dry bilge. Hope this helps, Alan.

serpro-uk
serpro-uk

Posted: Tue Dec 22, 2015 8:22am

Post Subject: Bilge draining

Yes, they soak up oil, but they also soak up water, fuel, water, diesel and more water, in fact any liquid. Pretty pointless if what all you want to do is exclusively absorb oil, fuel, diesel or any other hydrocarbon. Whilst on the subject of using baby nappies in bilges, has anyone ever seen what happens when one of these is left unattended to point of absolute capacity? The fact of the matter is that they can do one of two things. Firstly they can leach the gelling absorbent back into the water and into your bilge and then secondly they can burst and then the whole packet of gelling agent is spilt into your bilge. The risk of this agent getting into your pumps and separators is real. The cost of repairing them unreal. The gelling agent inside a baby nappy, or diaper, is a sodium polyacrylate (a type of polyacrylic acid in powder form), a super polymer and is VERY hydrophilic â it loves liquid, any type of liquid. Now, a baby nappy contains around 4-5 grams of sodium polyacrylate in powder form dispersed into the fluff in the middle of the nappy/diaper. Sodium polyacrylate has the potential to absorb around 30 times its own weight in liquid, and it needs time to do this. When the diaper eventually splits, or bursts, you will find little globules that are quite slippery to the touch and even more difficult to remove once dispersed throughout your bilge. There is usually some additional fluffed cotton product which will absorb around 25-27 times its own weight but this in itself will not hold liquid in suspension and will leach whatever it has absorbed back into the bilge eventually. What is quite interesting is how much a baby diaper is designed to absorb. Depending on the brand used they can absorb up to an average of 130.5ml (ref: Shramko et al. 2013) which is really a very small amount when you are looking at the volume of liquid that could be in a bilge and looking at pricing at an average of 20p per nappy these are not cheap. Whilst not knowing how much liquid is in any given bilge we might say that there is around a 10% solution of oil floating on the water. This means that you will only be absorbing approximately 10ml of oil per nappy, roughly. So, if a baby diaper costs 20p and absorbs 130ml, and that is a mixture of water and oil, how does this compare to professional absorbent pads that are designed to only absorb oils and fuels. You can buy lightweight oil only absorbent pads for as little as £34 for 200 which works out at around 17p each and each pad will absorb approx 600ml. So they cost less than a nappy and absorb 4 times the amount of oil, and no water, so in real terms a vast amount more oil that a diaper. Additionally they are not made with sodium polyacrylate, they are made from melt blown polypropylene, so there is no leeching of any substance to further foul your bilge area. You can leave them in the bilge until saturated and as they are hydrophobic they float on the water and wick the oil from itâs surface. The oil only pads are readily available and there are versions available in small quantities and modified to use specifically in bilges. They are not expensive, which is the usual excuse for not using them, and can be bought online. To us itâs a no brainer.....

Tony-B
Tony-B

Posted: Tue Dec 22, 2015 11:38am

Post Subject: Bilge draining

Well, to quote: "they would say that, wouldn't they". The above post is from a commercial organisation (Google the name) supplying absorbent pads and products. What he does not say is that if you leave such pads in us for a long time they get so saturated they drip oily water all over the place while you extract them from the bilge and put them in a polythene bag. I also question the prices quoted. 3M products cost an awful lot more and the cheapest pads I can find from canal outlets were about 50p each two years ago. I also suspect the price quoted does not include P&P. You may get them for that price if you are willing to risk Ebay and buy in a large enough quantity. I used to use pads and still oil absorbent ones under the engine but for general water absorption I find disposable nappies just as good and a lot cheaper. However take heed to the advice about what happens when they split and change them frequently.

robinj100
robinj100

Posted: Tue Dec 22, 2015 6:14pm

Post Subject: Bilge draining

I have found that nappies work well for small amounts of liquids both in the cabin bilge and un der the engine, as they absorb everything. For an alternative a wet and dry vacuum cleaner also works well, especially in the bilge sump to get that last bit out that the pump can't. Cheers. Robin

serpro-uk
serpro-uk

Posted: Wed Dec 23, 2015 7:43am

Post Subject: Bilge draining

Well, just thought we were giving some helpful advice. Yes we are a commercial organisation but we didn't try and hide it. Neither did we link to products in the text. As to the price, the price is correct and smaller amount are available and you don't have to buy from Ebay. As to usage, any item placed in an oil/water medium is going to have some surface water on it when withdrawn, it is inevitable. That residue is going to a have a micron thickness of oil on it, but it won't be from the pad, it is from what is remaining on the surface of the water. The same would happen when trying to withdraw a nappy through the liquid. The usage of the super absorbent pads is recognised worldwide and we use them, as do other manufacturers, in the OPA90 spill kits used by ocean going vessels. Additionally as we are members of the British Marine Federation and also the Yacht Harbour Association we feel we are giving best advice regarding the absorbtion of oil from, and on, water. We are in agreement with tony-b when he states on his training website "I would simply put an oil absorbing bilge mat in the engine drip tray".

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