I think this might be the schooner Fanny blipped the other day, caught as it returned to port in a squall. From some angles you could see the upturned prow.
The geography where I live is such that you can usually see rain approaching from the west, often breaking on the hills of Cowal and sparing us. This evening I took a few minutes in the garden before a final read-through of a piece of writing I've been working on all day. The air was utterly still, soft, grey, warm and heavy with moisture. Everything in the garden is about to burst into bloom and I took many photographs of straining buds in the gathering gloom.
But it was this ghostly shape hovering on the horizon that caught my attention. It appeared and disappeared a dozen times as drops began to fall and I was chased inside. Shades of 'The Ancient Mariner,' I fancy.