Canal Boat — November 2017

canalboat.co.uk Canal Boat November 2017 17

LETTER OF THE MONTH

LETTERS

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I read Kevin Blick’s article (CB, October) with great

interest, and hope that I might be allowed to offer

some thoughts of my own. My own perspective for

this is a little unusual – my wife and I have been

clocking up four weeks a year aboard hire boats for

over 30 years now, and for most of that time I have

deployed a GPS which accurately displays speeds

accurate to 0.1 mph, so my views are based on sound

facts rather than guesswork.

So let’s get down to the fundamentals. A boat’s

prop works by drawing water through itself. This water

usually has to come either from the sides or beneath,

as the prop is generally too close to the hull for much

water to be drawn from above. If the prop is unable

to pull water through itself freely, as is the case, for

instance, when the cut is either narrow or shallow,

then no amount of extra throttle will change that fact.

Think, for instance, how all narrowboats labour when

leaving locks, as well as when negotiating narrow

bridge holes or aqueducts. Thus the maximum speed

attainable by any boat is usually determined by the

profile of the cut itself. Incidentally, everyone who has

ever taken a boat onto a navigable river will know that,

wind and current aside, any boat feels far more lively

on a river than on a canal.

In a few places – Duke’s Cut springs to mind here

• you can actually feel the change as the boat makes
  the transition from ‘wide and deep’ to ‘narrower and
  shallower’, or indeed vice versa. Conversely, I suspect
  that no one has ever achieved a true 4mph anywhere
  on the Macclesfield!
  All this means that for the vast majority of the
  canals, the existing 4mph limit is in fact no more than
  an aspiration. Even attaining this speed is usually
  impossible, and any thoughts of maintaining an
  average of 4mph over an hour or more remain mere
  fantasy, especially as you will invariably be slowing
  down frequently for moored boats.
  I use my own bespoke software for planning my trips,
  and I never plan for more than 3mph for UK canals,
  and for our forthcoming trip on the Southern Oxford,
  I have assumed an average of no more than 2.5mph.
  Some stretches of, for instance, the Grand Union or
  the Trent & Mersey do permit slightly higher speeds, as
  would the Caledonian Canal, though sadly I

have no personal experience of boating on the latter.

Now let us consider the matter of passing moored

boats. There are actually two separate issues at

play here, as both speed and throttle-setting are

relevant. Happily, most narrowboats these days

have efficient bows which produce relatively little

wash and very few boats have the square sterns that

produce noticeable stern wash – indeed the stern

wash produced by most boats is pretty negligible

these days.

My experience is that the thing that peeves most

boaters, myself included, is that of having the boat

pulled away from the bank by passing traffic.

The important thing to understand here is that the

pull is not being produced by bow or stern wash, it’s

that pesky prop trying to suck loads of water through,

as the steerer is using too much throttle. It doesn’t

matter how slowly that boat is moving, it’s the use of

excessive throttle that will do the damage. In France

we had the interesting experience of trying to moor a

boat with a heavily loaded peniche passing us in the

opposite direction.

This boat was only doing, maybe 1.5mph, but

because the skipper hadn’t throttled back, the pull on

the ropes was so severe that it was all that we could

do to succeed in holding on to just one of the ropes,

such was the pull on them as the peniche passed.

I would conclude by wholeheartedly agreeing with

KB’s assertion that the blame for excessive speeding

is equally shared by both owners and hirers. I believe

it’s about 50/50, and has been for many years.

CHRIS DODGE, via email

Using too much throttle is actually pointless – and here’s why

My dad has recently become disabled and needs

a wheelchair. So wherever we want to take him by

car, needs to have wheelchair access.

Do you know of anywhere within driving distance

of say one hour from Newcastle upon Tyne where

he can see the canal, preferably with a pub nearby

and/or disabled toilet facilities? He loves the

open water and now he’s become disabled it’s

something he and my mam can no longer do as

he can’t drive now and everything needs to revolve

around wheelchair access and a toilet.

ANN, via email

There aren’t many canals that far north but how

about Ripon, with a pub and accessible tripboat?

Where can my disabled dad see a canal?

It doesn’t take much to upset things