On my 40cc I have stainless tube bars running from under the stern cleats over the cockpit locker lids to the rear attachment for the jackstays it is discus padlocked over the jackstay point . The cockpit locker lid will only open about 2in. I have similar bars on all vulnerable hatches and all are keyed alike ,6 locks 1 key. The good folk of Gosport have a reputation for being a bit light fingered. Geoff