Crossing The Weir

The Lagan Weir Control Centre is a licensed VHF radio base station. Vessels wishing to cross the weir must contact the control room for permission.

Channel Number……………………………………71
Frequency…………………………………..156.575 MHz
Call sign…………………………………….Lagan Weir

During normal tidal and river conditions the weir gates are raised on each falling tide to impound the river upstream. The gates are lowered again when the tidal range rises above the impounded control level for the river. A horn is sounded to warn boats when the gates are about to rise. The gates can also be raised to quay level to act as a barrage for flood protection from exceptionally high tides, and to deal with pollution incidents. Boats are not permitted to cross the weir at these times.

Navigation across the weir is possible for a period of approximately two and a half hours on either side of high tide.
The Lagan Weir navigation system comprises multi-lamp traffic lights. Floating safety booms lie across the non-navigation openings, and rise and fall boom frames are positioned across the two passages for boats. Both systems are on the upstream side of the gates.