Need a boat to Pass Under a Bridge? When passing under a bridge with your vessel, there are various things that you will need to take into consideration, some of these being the air draft and bridge’s clearance.
Air Draft is a term found on the specification chart for most boats and is a measurement that could be very important when purchasing your boat. A vessel’s draft is the distance measured between the top of a vessel’s highest point to its waterline.
Vertical clearance is the distance above the air draft that allows the vessel to pass safely under a bridge. Failing to consider air draft may result in being unable to calculate a vessel’s vertical clearance during a passage can be catastrophic.
A bridge’s clearance can be found displayed on charts as measured from the surface of the water to the underside of the bridge at Mean Highest High Water, which is the most restrictive clearance. The Mean Higher High Water (MHHW) is the average height of the highest tide recorded at a tide station each day during the designated recording period. It is used to measure the navigational clearance, or air draft, under bridges so that vessels can pass through safely.
For our MAKAI M37 Power Catamaran the air draft, as measured from the waterline to the top of the roof is 3130mm which is 10ft 3in. The loaded waterline is the point on the hulls where the water reaches the boat loaded with fuel, water and other small items such as safety equipment.
If you have any other questions, we are always up for a chat and a challenge! Contact us today to find out more about our vessels and any other enquiries you may have. Follow us on Facebook and Instagram to stay up to date with all the latest news on Makai Yachts.