It took 120 years from the first proposal in 1677 for a navigation between Chelmsford and Maldon until the works were complete, due mainly to the opposition of the port of Maldon who feared the loss of revenue. Two schemes were proposed after surveys in 1733 by John Hore, both again being opposed by Maldon.

More success resulted from two surveys in 1762 by John Smeaton & Thomas Yeoman. The proposals were supported by Chelmsford, but again opposed by Maldon. In 1765 Yeoman produced another plan with which Chelmsford applied to Parliament for a Bill. Maldon again tried to counter his proposals, but an Act was passed in 1766 to make the river navigable between Chelmsford and Maldon within twelve years. However, despite several meetings, it was impossible to raise the £13,000 required.

Peter Muilman, an enthusiastic Dutchman, proposed two schemes in 1772, but these were not progressed.

With the success of the canals across the country, Chelmsford inhabitants felt isolated and revived the possibility of a navigation between the town and the sea in 1792. The continued opposition of Maldon led to a proposal with the navigation terminating not at Maldon, but to the north, at what is now Heybridge Basin, on the Blackwater. The new line was surveyed by Charles Wedge under the direction of John Rennie, and, again under Rennie’s direction, in 1793 by Matthew Hall. These surveys showed that, by bypassing Maldon, the length of the navigation would be increased by two miles to 13 1/2 miles. Despite Maldon’s opposition, the resulting Parliamentary Bill became law on 17 June 1793, and established The Company of the Proprietors of the Chelmer and Blackwater Navigation. Soon after the Act came into effect on 15 July 1793, construction began on improving the existing river near Chelmsford, under the nominal direction of John Rennie, although actually by his assistant Richard Coates. Apart from the long 2 ½ mile cut between Beeleigh and Heybridge Basin and the shorter ½ mile cut from river to the terminal basin at Springfield, a number of short cuts were made for locks at the mills. Thirteen locks were provided, in order from Chelmsford basin, Springfield, Barnes Mill, Sandford Mill, Cuton, Stonhams, Little Baddow, Paper Mill, Rushes, Hoe Mill, Rickett’s, two at Beeleigh and the sea lock at Heybridge Basin. The two at Beeleigh were necessary for the navigation to join the Blackwater, and thence to continue through another cut to Heybridge Basin and Colliers’ Reach.

In a counter measure, Maldon employed Benjamin Henry Latrobe to report, in 1793 and 1794, submitted as a Parliamentary petition in March 1794, but was vigorously opposed by the Chelmer and Blackwater, and dropped.

Early in February 1796 the ship Chelmer entered Heybridge Basin with a cargo of wine from Oporto, the first ship through the sea lock. On 23 April 1796 the brig Fortunes Increase entered Heybridge Basin with 150 chaldrons of Sunderland coal, which was then transported to Little Baddow and thence by wagon to Chelmsford. Also in April, a barge was loaded with flour at Hoe Mill and proceeded down the navigation for London. After the last stretch of the navigation from the river to Springfield Basin was completed, the navigation opened on 3rd June 1797, by which time the cost had risen to nearly £50,000.

In December 1797 heavy rainfall caused flooding, forming shoals, impeding traffic, leading to coal shortages in Chelmsford. The problem continued with each flood, and in March 1799 the navigation committee asked Lord Petre to see Rennie to survey and remedy the defects. Rennie carried out a survey in May 1799, reporting in June, that he would put in hand the remedial steps necessary. Rennie was again engaged in 1805, after the six mills along the navigation complained about loss of water at the locks. Following a survey in November 1805, he recommended improvements costing £4,918 for settling the millers’ issues.

The facility of cheap coal led to Chelmsford’s first gas works in 1819, the second in Essex. The dividends paid out began falling after 1838 when the Eastern Counties Railway opened through Chelmsford, but the navigation benefited from the fact that there was no direct line between Maldon and Chelmsford, the sole rail access being via Witham, open in 1848.

In addition to coal, goods carried included timber, bricks, stone and general cargo inwards, and grain and flour outwards, using wharves near Little Baddow, Boreham, Ulting and Heybridge as well as the terminal ones at Springfield and Heybridge Basin. The barges used, of 25 tons capacity, were 60ft x 16ft (the maximum the locks could take) and were flat-bottomed of very shallow draught (2ft) as the navigation was the shallowest in the country. In the 1960s the sea lock was lengthened by about 25ft to 107ft x 26ft, by building a new electrically-controlled sliding gate downstream of the lower gates, to enable coasters bringing in Continental timber. However, more recently the sliding gate had become ill-fitting and with the financial assistance of the local council and Essex and Suffolk Water, the Company reinstated the lower gates to Rennie’s design around 2000.

There is no doubt that the navigation helped Chelmsford grow from a small market town to take advantage of the railway and become the important centre it is today. The navigation was in use commercially until 1972 with timber from coasters at Heybridge Basin taken up to Chelmsford. Heybridge also developed after the opening of the navigation, with William Bentall’s iron works opening here about 1811. Bentall’s works grew to occupy 13.25 acres by 1900.

An interesting side-line of the navigation, since the early 20th century, is the commercial growth of cricket bat willows, trees being planted and felled annually once they have reached about 20 years.

Following the original Company of the Proprietors of the Chelmer and Blackwater Navigation Ltd going into administration in August 2003, Essex Waterways Ltd took it over in November 2005 for day to day running, as a subsidiary of the Inland Waterways Association, although ownership remains in the Company hands. Today the navigation is use by pleasure craft, including three boats, which run trips from Paper Mill Lock near Chelmsford or Heybridge Basin. There is a proposal for a new lock in Chelmsford, which would replace the automatic weir to link with the navigation, which the IWA have been campaigning for 35 years.