Home :: Oil in your Bilge?

Oil in your Bilge?

When we look around the web for uses for our products it never ceases to amaze us at the ingenuity of people to try and save a few pennies by using alternatives that aren’t meant for the job that the user is putting them too.

One of the commonest we have found is the use of baby’s nappies being used in the engine compartments and bilges of boats and yachts. Whilst on first glance this might seem like a good use for a commonly available product, not one of the users, in the forums where they are talked about, actually accepts that they are particularly useless for the job in hand.

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 – 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 it’s 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 it’s a no brainer.....

Find our range of marine absorbents here........

 
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