Hi Vanessan - I've consulted the log book to confirm details (Griff tells us off if we don't maintain the log!).
We were underway on Breydon by 10:20. Aiming to arrive Yarmouth YS just over an hour before high tide. Anticipating 6ft9inch of air draft. The ranger approached from Yarmouth at some speed (estimate >15mph) performed a 180 and came alongside us. They advised the bridge was already at just 6ft3inch air draft with more than an hour to go before high tide.
I was impressed with the Ranger service. They advised each craft behind us. Most vessels did a 180 and sought berthing at the south end of Breydon. Important to note that the Ranger recognised BA as a private vessel and didn't advise us to take a course of action. Rather, they advised us of the circumstances so we could take appropriate action. Quite right too. I believe they gave more direct advice to hire vessels, as it should be.
At around 14:00 the Rangers came back to the moorings on the south rivers entering Breydon and advised the bridge now offered 7ft. They assessed each vessel and advised on crossing times based on height above water line.
We crossed Breydon, made the turn at Yarmouth, lowered mainmast and foremast and went under the bridge with 7ft 9inch to play with. Windscreen up at 7ft 7inch.