Sunday, August 19, 2012

Did they have varifocals in 1793?

After our nightmare on our last trip when our tunnel light failed in Braunston tunnel, I was not looking forward to going back through this week.  I did however have a secret weapon.  Having replaced the tunnel light bulb, I now know how knackered the old one was.  Now we can actually see.

What our new brilliant light revealed in the 2042 yards underground was that William Jessop, who built the tunnel in 1793 was either a) drunk, or b) a wearer of varifocal lenses.  (Wearers of the latter will testify to the distorting effect of these optical marvels, which I maintain is the reason I have lately become useless at reversing a car.), or c) having a laugh.

I can forgive Mr Jessop and his mate James Barnes for starting from both ends and missing in the middle thus causing the infamous S bend on which so many of us have modified our paintwork.   What our new bright light has now revealed is that they couldn’t even get the straight bits straight. I don’t know what Jessop and Barnes were playing at. Was this some kind of precursor to slalom racing? As far as I can make out it’s like a python that has eaten several rats. Gently bending this way and that and changing width at frequent intervals.  It’s like they bought a lot of bits of second hand tunnel from elsewhere and stitched them all together.  The old trick of trying to keep a fixed distance from one of the walls is a waste of time.  So much do the walls wobble that you end up weaving a very serpentine course through.  Of course when you do meet a boat coming the other way, sod’s law dictates that it is when your boat is either on a tack across the centre line or should you be going straight, it’ll be at a place where a lump in the wall jumps out to scrape your vessel.

To check that it wasn’t just me that had problems I did a quick search of the canal forums and found that I am indeed not alone.  One correspondent says he would accept a hundred mile detail to avoid Braunston tunnel.  I wouldn’t go that far, but don’t expect me to enjoy the trip next time through.

Whilst I’m on the subject of sod’s law, here’s another example.  Somewhere in the planning for Watford staircase locks in 1814 there must be a document that reads. “Lo it is written that whenever a boater shall arrive at these locks, he shall report to the lock keeper before entering the flight, and the lock keeper shall forever be at the opposite end of the flight from the approaching boat, necessitating the boater to endure a climb and descent (or vice versa) of 52ft 6ins each way to get permission to proceed.” 


Andy Healey said...

What about the narrow locks from the River Severn in Stourport, why where they not built in line, we had difficulty in a 62', how does a 70' make it? Surely they have not moved since been built, Then there is the Shroppie by wash outfalls, get yourself all lined up, then the bywash pushes you into the wall.

Peter Lee said...

Give those old navigators and engineers a break! Just imagine building a tunnel yourself with a pickaxe, shovel and horse and cart to do it with! Oh, and maybe a bit of black powder and a rope or two.
They not only started at both ends - they sank what are now the ventilation shafts and dug between them simultaneously. This meant a fancy bit of surveying to work out how deep each shaft needed to be - and then they had to work out exactly which direction to dig. Easy these days - but not when the only tools were plumb-bobs and such. It's a wonder they managed to get any sort of tunnel at all...
Makes you appreciate the skill (or maybe luck) of those tunnellers who got things more or less straight, though.

Anonymous said...

Oh my, this post could open a whole can of gripes - though I do agree about the alignment (or lack thereof) at Stourport!

Sue, nb Indigo Dream

p.s. tunnels make me feel squiffy - wheether they're bendy or straight :-)