Genuine question if you own a boat etc.
You are based in Dover of Folkestone - if you go for a little swim and arrive back at the beach, no passport required to re-enter the UK obviously!! But, if you went out fishing, say, over 3 miles out (either deliberatly or drifted due to the weather) and returned, would you need to take your passport with you to get back? 6 miles? 12 miles? Could you get to the French coast, not land, return without passport? If you got over half-way, would you have to inform the French authorities so they could (if they wanted) sail out, stamp your passport even though you have no intention of landing in France as you are in their waters??
Are there any specific rules regarding this? Thanks!!
I don't think that things have changed much since I used to sail cross-channel regularly in the 1970s and 80s. However what's below is from memory of 40 years ago, so no-one should rely on it for legal guidance!
There was no requirement to do anything unless and until you landed in a foreign port. When you did so, you were required to fly the Q flag at the yard arm, meaning "quarantine" in international code, and signifying that you'd arrived from a foreign country (from England in our case). You were then required to make your presence known to the port authorities and/or police, so they could check passports and inspect your boat if they wished.
When returning to your home country, the same procedures would apply on arrival from abroad.
That was the legal position anyway. In practice, at least in those days, port authorities weren't at all bothered about what small boats were doing, passport inspections were at best cursory, and I don't recall anyone ever boarding our boat to inspect anything. The chances of French authorities coming out to question you for going more than halfway across the channel were absolutely zero.
On one occasion, sailing to Cherbourg and arriving in the evening, we found that our auxiliary engine wouldn't engage gear. Our skipper was unwilling to go into the congested inner harbour under sail, so we dropped anchor off the beach, and two of us went ashore in our inflatable dinghy to seek assistance. The port offices were closed, and after some searching we found the gendarmerie. When we went in, we found two or three officers in a mess room. Neither their English nor our French was up to detailed explanations, and they seemed not at all bothered that we'd come ashore without following the rules. In the end we were basically told to sort it all out in the morning, so we had a quick beer in a bar and returned to the boat. After a rather bumpy night at anchor, we went ashore again, arranged for our boat to be towed into the harbour, and when that was done we could finally follow the official procedures.
With the fuss about illegal immigration, there may be more official attention being paid these days around Dover, but I imagine that sailing between the Solent and Cherbourg or the Channel Islands, as we did, is probably much the same now as it was then. I don't think we ever took passports with us when sailing to Alderney or Guernsey, that was treated just the same as sailing to another port on the south coast of England.