Don't stop! Keep going to San Vasse. Go on a ferry if you want to go to Cherbourg. Oh, and make sure you go to the deli (forgotten it's name, but in the cruising guides "you're sure of a warm welcome from Monsieur So and So"). Best of all he delivers all the booze you've been persuaded to buy from him to your boat in his old citroen van. Great value.
Thank you Mr B. So long since I've been there obviously forgot how to spell SV. It is lovely there though isn't it and great fun if you get in a bit early so that you can go up to watch the last charge for the lock gates!
Nowt wrong with Cherbourg, OK it does'nt have the charm of St Vaast but there's a few very nice restaurants around, and its a very nice town. I'd rather be stuck there than in Portsmouth or Poole!
The port of Cherboug was built a long time after Vauban went to his grave - he's 1650s, whereas Arthur Young writes about Cherbourg being built in 1788 or so. Bloody French. No sense of history. Now if you were in St Malo Vauban would be your man....
Cherbourg is one of the easiest places to get into. Keep an eye open for ferries arriving and departing, they use either east or west entrances, make sure you pass west of the port buoy near the inner harbour entrance, it marks the end of a reef that sticks out then head straight for the marina just west of the big Gare Maritime building. Again watch for the ferries, their berths are just east of the Gare Maritime building. Marina visitor berths are the first 3 from east, clearly marked 'Visiteurs', pontoons N, P, Q I think, access to the marina is at all times, no sill or anything, plenty of water. There is also a waiting pontoon as you enter in case everywhere is full. Have a good time, we quite like the place even though you will hear more english than french around the shops. We use La Regence (good, moderate price), Cafe De Paris (good but occasionally a bit mean with portions), these and others like Vauban are on Quai Caligny en route to Carrefour Hypermarket. La Ciboulette is good (not pricy) as is Grand Goosier (which is superb but can be expensive if you get carried away, smarter gear advised but not essential), these 2 are up the road opposite the Capitanerie then make a right turn and they are on the left. La Taverna in the main square (up road opposite middle of Marina) does a good cheap lunch either inside or out on the terrace, everything from Moules Frites to salads via steaks.
Look up www.ville-cherbourg.fr/portsPlai.htm for more info, including restaurant addresses/tels. Harbourmaster will usually give you a folder with a map and other useful stuff. Visit the Normandy Landing museum at the fort on the hill (ice axe and crampons walk), Cite De La Mer maritime museum by the ferry port (inc nuclear submarine).
As robin says, cherbourg is easy, but do check a chart carefully, there are a lot of rocks and reefs - all well buoyed but don't cut corners
St Vaast is not really a lock - it has gates that are "free flow" HW-3 to HW+3 (ish) no access at other times.
It is advisable to time your arrival to coincide with the gates being open. The approaches to St Vaast are rather tricky at low tide - and there is precious little shelter from Easterlies
Cherbourg is the easiest place to go to - plenty of space, safe and accessible in all weathers. Its a good jumping off place to St Vaast or the Channel Isles. If it blows up you can safely leave the boat and catch the ferry back. It does perhaps lack a certain amount of charm as some of the other places mentioned (st vaast) but is a worth while destination in its own right.
Formalities are relaxed in the extreme - if arriving on a weekend there is usually a HM's rep in a dory who will direct you to a berth and will probably come around for the cash as well. Otherwise take any vacant visitor's pontoon slot - these tend to be small pontoons with hoops at the end rather than nice sensible cleats; depending on your size of boat you might have a lot hanging over past the end of the pontoon but its very sheltered. Chantereyne (the marina) has its own website - cant remember its URL.
I'd recommend the facilities in the Capitainerie rather than the dodgy ones on the quayside. Generally its a very cheap destination and has all the facilities you could want.
Still there last summer - went from the beach at LW across the oyster beds "road" - "boated" back to the ramp by the port office at HW - kids loved it..
Make sure you have a large scale chart of the harbour. Crewed for a skipper a few years ago who had been visiting for some 20 years, en route from Guernsey. Sea fog rolled in and we had real problems finding the marina once inside the outer harbour! Spent some three hours going around in circles dodging the ferry. Found out the next day that we could have called the harbourmaster who would have directed us in.
When are you thinking of going (or have you already been!!)? We are planning our first cross channel trip for early August and I was going to put a note of the forum to see if anyone wanted to cross in company. The attraction for Cherbourg for our first crossing is its access on any state of the tide. We will be more adventourous once the first crossing is under our belt.