"The Louth Navigation was a canalisation of the River Lud. It ran for 11 miles (18 km) from Louth in Lincolnshire, England, to Tetney Haven, at the mouth of the Humber. It was authorised by Act of Parliament in 1763 and completed in 1770, under the supervision of the engineer John Grundy Jr. and then by James Hogard. Eight locks were required to overcome the difference in altitude, six of which were constructed with sides consisting of four elliptical bays, a design only ever used on this canal in Britain.
The Act did not provide the normal provisions for raising capital for the construction, as finance could only be obtained by leasing of the tolls. When completed, the commissioners leased the tolls to Charles Chaplin, who held ten shares and was also a commissioner, for an initial period of seven years. When the lease was due for renewal, no other takers were found, and Chaplin was granted a 99-year lease, despite the fact that the Act did not authorise such an action. He collected the tolls but failed to maintain the navigation. When complaints were received, a new Act of Parliament was obtained in 1828, to alter the tolls and legalise Chaplin's long lease. The lease was transferred to two railway companies in 1847, and reverted to the commissioners in 1876. The operation was a moderate success until the beginning of the twentieth century, when there was a rapid decline in income, and the canal formally closed in 1924.
Because the canal also acted as a channel for land drainage, it was not subject to infilling, and is now a designated main river, managed by the Environment Agency, with drainage of the surrounding land managed by the Lindsey Marsh Internal Drainage Board. It acts as a feeder for Covenham Reservoir, from which treated water enters the public water supply. Water from Waithe Dike supplements the supply, effectively flowing upstream along the canal, and when required, additional water is pumped into the canal along a pipeline from the Great Eau.
The Louth Navigation Trust was formed in 1986 to promote the canal as an amenity and has established a base in a restored canal warehouse in Louth. A feasibility study for restoring the canal for navigation was commissioned in 2004."
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The Former Lock
This lock is one of the best preserved lock on the former navigation. It is a fine example of the barrel sided lock that is an unusual design of some of the locks on this canal rather than the straight sided locks usually used every where else in the UK.
This design was used because the soil composition in the area was slightly unstable and put pressure on straight sided locks.
A modern concrete road bridge now crosses the middle of the lock.
The Louth Navigation Trust carried out some preservation work in 2006, but if the canal is to be fully restored to working order they will have to find a way to deal with the modern bridge that makes the lock unusable.