Navigation Transit Markers are posts placed alongside a navigation to allow powered craft to check their speed. Examples of these markers can be found at several locations along the

River Thames The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, se ...

in England. A navigation marker consists of a black and white ringed pole surmounted by a red open triangle. The configuration of the markers is made up of two pairs, each pair having one pole behind the other, and the pairs being separated by a set distance along the bank. Timing starts when the first two markers line up, and ends when the second pair line up. For a craft to be within the speed limit, it should take a minute or more to reach the second pair of markers after passing the first pair of markers. On the upper reaches of the Thames, the speed limit is 8 km per hour or 133.3 m per minute, and so the markers are set 133.3 m apart. On the River Thames, there are markers on the reaches above

Teddington Lock Teddington Lock is a complex of three lock (water transport), locks and a weir on the River Thames between Ham, London, Ham and Teddington in the London Borough of Richmond upon Thames, England. Historically in Middlesex, it was first buil ...

Sunbury Lock Sunbury Lock is a lock complex of the River Thames in England near Walton-on-Thames in north-west Surrey, the third lowest of forty four on the non-tidal reaches. The complex adjoins the right, southern bank about downstream of the Weir Ho ...

Cookham Lock Cookham Lock is a lock with weirs situated on the River Thames near Cookham, Berkshire, about a half-mile downstream of Cookham Bridge. The lock is set in a lock cut which is one of four streams here and it is surrounded by woods. On one sid ...

Sonning Lock Sonning is a village and civil parish in Berkshire, England, on the River Thames, east of Reading. The village was described by Jerome K. Jerome in his book ''Three Men in a Boat'' as "the most fairy-like little nook on the whole river". Geogr ...

Day's Lock Day's Lock is a lock on the River Thames near Dorchester-on-Thames, Oxfordshire, England on the Dorchester side of the river. The pound lock was built in 1789 by the Thames Navigation Commissioner. The lock is across the river from the s ...

and

Osney Lock Osney Lock is a lock on the River Thames in Oxford, England, where the village or island of Osney is next to the river. The first lock was built of stone by Daniel Harris for the Thames Navigation Commission in 1790. Across the weir poo ...

References

A User's Guide to the River Thames
{{DEFAULTSORT:Navigation Transit Markers Water transport in England Geography of the River Thames

See also

References