The Brindley's Great Cross was made up of the Trent & Mersey Canal which eventually linked the navigable R.Trent near Nottingham to the Mersey. That made an inland transport link between Hull on the east coast to Liverpool on the west coast - and formed the northern and eastern arms of the cross. Secondly the Staffordshire and Worcester Canal linked the R.Severn at Stourport to the Trent & Mersey at Gt. Haywood - which linked Bristol in the southwest into the rest of the system, forming the western arm of the cross. Finally the Oxford and Coventry canals, together, made the southern link from nearby Fradley Junction on the Trent & Mersey canal to Oxford (and therefore London) on the R.Thames.  All the other canals came later (and there were many) and linked into the basic great cross structure.  One of the main centres of industry in the 1800s was Birmingham, linked by canal and near to the centre of the cross of the original canal system.  Birmingham becoming Britain's 'second city' was therefore no accident and resulted principally because of the enhanced transport infrastructure of Brindley's canal system. Birmingham and the Black Country is now interlaced with canals, forming a generalised system called the 'BCN' (Birmingham Canal Navigation).  It is said that the BCN has more miles of canal than Venice (although that claim is debateable) - and the BCN is apparently cleaner too.

As the main architect of our main canal system, Brindley set the standards by which most of the canal infrastructure is based.  He designed the system around the premise that lock chambers would be 7ft wide and 72ft long.  This set the standard for maximum boat dimensions, which in turn set engineering standards for bridge widths and the whole nature of the navigable dimensions of the system.

To travel up and down hills, the system used locks to lower or raise the boat from one level to another.  Most canals were actually a bit like a stream travelling downhill from it's summit level.  To use the locks meant a constant supply of water was needed, principally from the summit level. The more locks on the system, the more water would be required - so keeping locks to a minimum meant that less water was needed and the cheaper the canal was to build. Building a lock is expensive. So to keep locks to a minimum, these early canals favoured following the natural contours of the land to avoid going up and down hill.  These early Brindley designed canals are known collectively as 'Contour Canals'.  Passage of goods along these routes was relatively slow in the early days - but then time wasn't a problem then.  As the railway companies started to compete with the canals, slow canal passage became a problem - and later canals were designed differently (Telford).  We on Willow do like the narrow contour canals - they're our favourites because of their narrow intimacy with something different of interest around every bend.

As the years went on there was demand on the canal engineers to try and reduce the time of canal transport, in an effort to compete with the speed and carrying capacity of the railways. Canal engineer Thomas Telford approached the building of subsequent canals in the mid 1800s quite differently to Brindley. When possible Telford chose a direct straight route for his canals.  To overcome hills and valleys he would make cuttings through high ground and then use the dug out material to construct embankments over low ground - called 'cut & fill', it was a construction method similar to methods used in building a railway.  When locks were necessary they tended to be in flights rather that singles spread out over a distance. If necessary a tunnel was used to go through a hill rather than around it.  All of this meant that canal transport was speeded up on Telford's canals, but they did tend to need a larger water supply and were more expensive to build. 

As time went on newer canals were made 'wide beam'.  As I understand it, this wasn't generally to increase the size of each boat, but designed to allow two 70ft boats to through locks together.  Once boats could become motorised, a 'motorboat & butty' (also known as a 'working pair') could pass through a wide beam lock together 'breasted up'.  These were two boats acting together - a 70ft motorised narrowboat which towed a second unpowered 70ft boat (the butty boat)., thus having almost double the carrying capacity.  Out on the canal the motor boat towed the butty boat behind it on long tow ropes, but on arriving at a wide lock the two boats would 'breast up' and be worked through the lock at the same time - saving time. 

A classic example of the difference of the later wide beam canals compared to the earlier narrowbeam contour canals is to compare two well known canals - the Oxford compared with the Grand Union.  The main route north from the Thames was originally via the narrowbeam Oxford canal which followed the natural contours of the land with tortuous bend after bend.  Because that route was so slow trade eventually transferred almost entirely off the Oxford and onto the much later, and more direct, wide beam Grand Union route.