Wanderer Vagabond

From my trip up the Trent a while back I'd say you'll have no problem getting from Keady to West Stockwith on the tide, we timed it perfectly and went in on slack water, easiest turn possible (call up the lock-keeper when you are about a mile away/20minutes and ask whether the tide is still flooding). Similarly from West Stockwith to Torksey. Where we 'ran out of tide' was between Torksey and Cromwell Lock, the tide had turned before we reached it so pushed into the ebb tide for about half an hour. What I could never get my head around was why the tide on the Trent floods for 2 hours and ebbs for 8 hours, what happened to the 1/12ths rule?? .