YOUR BACK CABIN ( CB, Jan) refers to the extra weight of water on a lock top gate “... especially if it’s miles to the next lock”.
Surely, this is an old chestnut? The weight of water depends on the head not the distance. We have just drained down the Somerset Coal Canal for maintenance work and the weight of the water held back by our stop gate was the weight of the three feet of head – not the nine-mile pound of the Kennet & Avon beyond it.
It would be the same if the next lock was only six feet away. Wouldn’t it? Somerset Coal Canal
Company, via email
Fair enough, this one’s discussed in pubs everywhere – the point is: don’t force the gates against the water with the boat – Ed.