If the vessel was enclosed by lockgates at either end, then by allowing
water to flow in from a measured source so as to raise the water in the lock
by a standard height, you could read off from a chart, the displacement of
the vessel, against the quantity of water used to raise the height.
----- Original Message -----
From: "Jason Lucas" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, January 16, 2004 11:37 AM
Subject: Re: Weighbridges
> Yes, you've got a point. I'm beginning to suspect that the source
> article may be incorrect.
> On Fri, 2004-01-16 at 07:23, The Webmistress wrote:
> > on 16/1/04 12:37 AM, Jason Lucas at [log in to unmask]
> > > "Scales were not used in the original weigh locks. As boat entered the
> > > weigh lock, the level of water in the lock rose, and by displacement
> > > boat's total weight was determined. Then the weight of the empty boat,
> > > which had been previously established, was subtracted to determine the
> > > weight of just the cargo"
> > Having travelled extensively on canals, I fail to see how a boat
> > lock makes the water rise... Displaces it, yes - but the displacement
> > cannot, surely, make the level rise... How did they stop the water
> > moving out as the boat came in, as happens every other time a boat
> > Maybe it is just too early in the morning.
> > Or maybe I have just used too many locks...
> > Jez