Modular Lock Gates
an innovative solution to a specific problem on our canals
The Dommett Modular Lock Gate is an innovative solution to a number of problematic situations on our historic canals. The Modular Lock Gate has been designed to complement traditional gates which are generally replaced every 20 years in a 200 year-old structure. The Modular Gate provides a sustainable functional solution for canal restoration projects which can take many years to complete. Traditional timber gates are a well-proven, time-honoured, and attractive feature of our canal system, and will continue to remain so. However, they are not always the optimum solution to some common problems :-
- Locks difficult to reach with modem lifting equipment, such as mobile cranes. Locks can sometimes only be accessed via a narrow tow-path, and can be some way from a highway suitable for mobile cranes.
- Long-running canal restoration schemes, where restored locks and their lock gates remain unused for many years, resulting in premature deterioration.
- Locks on canals which have a low frequency of boat traffic where timber lock gates are not regularly used, a fact which can considerably shorten their working life.
- Locks where maintenance is not routinely and regularly carried out. The lock may be on an isolated section of canal which is hard to reach, or may be due to an over-stretched maintenance budget.
Advantages of the modular gate
- The gates reflect the structural appearance of a traditional timber lock gate, and therefore do not look out of place in a 200 year old lock chamber.
- The Gates are constructed in relatively easily man-handled sections which can be easily transported to site, even along narrow tow-paths. A fully assembled timber gate can typically weigh 1.7 tones.
- Simple gate assembly within the lock chamber without the use of a large crane.
- The gate's main structure is made from high-quality steel sections which have been galvanised to give a minimum lifespan of 100 years. This compares to a timber gate lifespan of around 20 years, if well maintained and in regular use; if not, the lifespan can be considerably shorter.
- The cost of manufacture compares very favourably with that of a traditional timber gate.
- The steel components can be mass-produced to the same basic dimensions (therefore, unit cost will be less) with adjustable oak timber quoins being bolted to the sides to cater for small common variations in gate-widths on a flight.
- Future maintenance is much less frequent due to the steel construction, and, when it is required, can be accomplished much more easily. Individual steel and timber sections can be easily replaced without the need to replace the whole gate. This considerably reduces the call on a hard-pressed ongoing maintenance budget.
- The gates are less prone to wanton vandalism, where timber balance beams are often a target for those who wish to record their presence by carving names into the wood or those bent on setting fire to them.
- The use of expensive and slow growing oak is minimised. Each traditional Lock Gate requires 12 mature 250 year old Oak Trees to be felled. Over a 100 year period each lock would need timber from 48 Oak Trees.
- The lock gates have been designed with substantial steel box sections to resemble the visual solidity and profile of a traditional timber gate. Their appearance, therefore, does not jar with, or detract from, the visual integrity of a traditionally- built lock structure.
- The gates are stronger than a traditional timber gate; this is particularly the case as timber gates get older and start to deteriorate. An independent study by Swansea University Engineering Department found some fundamental weak points in the traditional timber gate design which was designed out for our modular steel alternative.
- The gate is lighter to open and close as its cross-members provide buoyancy.
- The gates do not suffer from the long term problem of weed growth roots penetrating the timber grain, thereby shortening the gate's life.
The development of the gate design is a partnership between the Monmouthshire Brecon & Abergavenny Canals Trust and the Kennet and Avon Canals' Trust. The modular gate is the brainchild of Richard Dommett, MBE, who has 41 years' experience in managing and maintaining canal infrastructure. He has considerable experience in traditional timber lock gate manufacture, fitting and on-going maintenance, so is eminently equipped to design out some of the inherent weaknesses in a traditional design. Members of the Kennet and Avon Canal Trust have been actively involved with Richard in developing a practical solution.
Working with Richard on the engineering integrity of the design is Swansea University Engineering Department, who examined the design in detail to prove its structural integrity.
The gate design was developed to meet the needs principally of the restoration of the Monmouthshire and Brecon Canal, where the process of restoration has taken, and will take, many years to complete. The MBACT partnership did not wish to replicate the problems seen on other slow-moving projects where new timber gates installed in early phases needed replacing by the time the canal was ready for opening.
Gates have been manufactured, assembled and installed without the use of heavy lifting equipment in a series of locks at the Ty Coch flight in Cwmbran on the Monmouthshire and Brecon Canal. This will act as our test-bed for the design.
The Ty Coch flight of eight locks is currently being restored by volunteers and trainees with strong support from Torfaen County Borough Council and with the aid of a substantial grant from the Heritage Lottery Fund. This 'Waterworks Project" is also supported by Derbyshire Environmental Trust, who are the administrators for the Landfill Community Fund Grant from Lafarge-Tarmac Ltd for the development of the Modular Lock Gate.
Visitors are welcome to come along and view the gate, but we would ask you to make a prior appointment with Richard Dommett who can be contacted at:
Modular Gates for Your Canal
If you are engaged in a canal restoration or maintenance scheme it might be of interested to you to know that through our 'Not-for Profit' Company 'MBACT Regeneration Ltd', the Trust can offer a range of Pick & Mix services.
- Initial technical assessment of your project to ensure that this design of gate will be suitable, and give you a guide price. This service incurs a nominal charge of £50 to cover time and travel cost (subject to reasonable time/travel distance)
- Initial survey and measurement of your lock prior to manufacture.
- Supply of high quality Modular Lock Gates in kit form, manufactured by our experienced team, fully galvanized, complete with timber coins, ready for self-assembly and fitting. Assembly training is provided as an integral part of this service.
- Full supply and fitting service.
If you would like to discuss these options please contact Richard Dommett MBE at: