I don't know anyone who uses white diesel in their boat. As for the statement that red is only slightly cheaper than white, that's poppycock. The last time I filled up, at Titchmarsh Marina on the Walton Backwaters, I paid £1.10 per litre. On the Broads, Goodchilds are usually the cheapest (I think at around £1.18 though I haven't filled up there this year so far). Both these costs are based on the 60/40 split, and are considerably cheaper than the £1.40ish that white diesel will cost you from the roadside pumps. If you are buying 600 litres, that makes a saving of around £130!!!!!