Passing under bridges can be dangerous if not done properly. Know the air draft of your boat (the height of your boat from the waterline to the highest part of the boat) and check the clearance available on the gauge board at each bridge every time you pass through. The helm should ensure the boat and everyone onboard, is prepared well in advance of reaching the bridge. Windscreens should be lowered and anything that has been placed on top of the vessel removed. Crew members must get to a lower part of the vessel and prepare to duck down if necessary. Life jackets should be worn by everyone out on deck. Vessels travelling against the current (into the flow) must give way and allow vessels travelling with the current (being pushed by the flow) to pass through the bridge first. Most bridges also have advance gauge boards in place so you can see the available clearance before reaching a bridge in order to plan your timings ahead of your arrival.
Potter Heigham and Wroxham bridges require the assistance of the bridge pilots if passable at the appropriate state of tide. Find out more
NB In all cases, tidal levels can vary considerably and so affect the above figures.
Clearance measurements for bridges given are at Average High Water during summer. There will be greater clearance near Low Water, especially at Great Yarmouth and in the southern rivers. Barometric pressure, rainfall and wind conditions affect river levels so caution should be exercised and bridge gauge boards carefully noted.