Diesel and grease in the waterway

IF I MAY, I would like to add to my confusion about carrying drinking water from the midlands to the south east by the Grand Union Canal, writes John Smedley.

This time it is more about the contents of the river, particularly the all too often traces of oil and grease shown by their 'rainbow' colours on the water.

Filtering methods

I realise there are to be filtering methods to make the water drinkable, but just what will these remove?

Of grease for instance, nearly all narrowboats are fitted with those screw-down grease providers for their propeller drive shafts, most being screwed down whenever a boat leaves its moorings, and they used so much that Midland Chandlers for instance sell 5kg tubs.

There is the Volvo propeller shaft bearing that does not need any grease, so should that be compulsory, to make the water less polluted?

[Here is a photograph of the Volvo propeller shaft bearing on our narrowboat that has never had any any grease in 23 years!—Editor]

And it can only go into the waterways, as the shaft bearing doesn't get hot so doesn't just disintegrate.

Overflowing into the water

And only last week I was waiting in the queue to get diesel from the canalside pump at Sawley Marina, and twice saw it overflowing into the water as boaters over-filled their tanks, with the diesel just left floating away. Though I admit to this happening to me, very quickly 'she' comes out with the washing up liquid squirter to get rid of it.

The result is no small amount of diesel and grease in the waterway. Will it be filtered out?