Seagull droppings

[William_H]

I have bought the little boat home for the winter. I have scrubbed a fair bit of mess off the decks. But there seems to be a remaining coating of white. Stuff. A scrubbing brush does help. But I wondered if there was something that will dissolve the mess. I have tried oxalic acid. I have tried caustic soda. Neither seem to do any better than plain water. Anyone got any iideas? ol'will

 

[johnalison]

I’m not sure about your white stuff. The stuff round here is generally brown. I generally just use water. If you wet the fouling thoroughly and just leave it for ten minutes or so it generally comes off easily enough. I occasionally use a ‘deck wash’ solution for thick or obstinate marks. After removal there is often a yellow stain, but this seems to fade on its own after a few days.

 

[neil_s]

A good bit of UK Winter weather without seagulls seems to shift it!

 

[Fantasie 19]

Most of the commercial bird poo cleaners seem to contain citrus - so maybe try a citrus based degreaser??

 

[William_H]

Thanks for the replies. I will try lemon juice. But it seems like rain over winter might soften and move it. ol'will

 

[LittleSister]

I only boffins would genetically modify seagulls to produce anti-gravity droppings which would float up and disappear into outer space.

 

[ylop]

Most of the commercial bird poo cleaners seem to contain citrus - so maybe try a citrus based degreaser??

Thanks for the replies. I will try lemon juice. But it seems like rain over winter might soften and move it. ol'will

The “citrus” cleaners use limonene from the skin of the fruit rather than juice. No idea if it’s any good for guano but your local bike shop will sell it for cleaning chains… which usually means your local car parts shop sells something identical at half the price for triple the volume.

 

[Puffin10032]

The main component of the white droppings is Uric Acid. It's not very soluble in water which is why birds evolved to excrete it rather than Urine to conserve water. It's solubility does improve with increased pH i.e. increased alkalinity so I'd guess that any product containing citrus acid would be even less effective than plain water. Soapy water might be more effective as it's slightly alkaline.

 

[OrangeOily]

The main component of the white droppings is Uric Acid. It's not very soluble in water which is why birds evolved to excrete it rather than Urine to conserve water. It's solubility does improve with increased pH i.e. increased alkalinity so I'd guess that any product containing citrus acid would be even less effective than plain water. Soapy water might be more effective as it's slightly alkaline.

Am I correct in thinking that common old BiCarb disolved in water is an alkaline?

 

[johnalison]

I think the cleansing and detergent properties are likely to be more important, allowing water to soften the offending marks. I can't imagine why the yachting magazines have ignored the need for trials on this important point.

 

[AntarcticPilot]

I looked up the solubility of uric acid and urates. This table (from Wikipedia) suggests that LOTS of hot water is required to shift it. Maybe sodium hydroxide (caustic soda) would help? It would also break down any fatty residues.

Solubility of urate salts (grams of water per gram of compound)

Compound	Cold water	Boiling water
Uric acid	15,000​	2,000​
Ammonium hydrogen urate	—​	1,600​
Lithium hydrogen urate	370​	39​
Sodium hydrogen urate	1,175​	124​
Potassium hydrogen urate	790​	75​
Magnesium dihydrogen diurate	3,750​	160​
Calcium dihydrogen diurate	603​	276​
Disodium urate	77​	—​
Dipotassium urate	44​	35​
Calcium urate	1,500​	1,440​
Strontium urate	4,300​	1,790​
Barium urate	7,900​	2,700​