It looks very much like a boat I followed out of Weymouth on the midday bridge lift. If so, he may have gone into Lulworth Cove; I went on to Warbarrow. At first, there was what looked like low cloud over the hills and I thought it would burn off. It didn't. It turned into a pretty thick fog with visibility down to 100-200 yards at times. I suspect that if he didn't have radar, he was following the coast round back to Weymouth. Not an unreasonable strategy, but the fog was thicker near the shore and there are a lot of reefs in that area (and they're not a "soft landing"!) It's at times like that when radar is a godsend. Hope he made it back safely.
If was certainly a peculiar fog in Weymouth Bay on Saturday. I didn't venture out but looking East out from the Pavilion there was a thick wall of fog obscuring anywhere beyond Lulworth (ish) but in land was clear and very warm.
Moved a boat from Lymington to Dartmouth on Saturday… didn’t see land once we passed Hurst Point until arrival at Dartmouth, except for a few breakers observed at Portland Bill on the inshore passage… I think the fog was unexpected.. inshore forecast said good visibility..