Factsheet - Cycling to School

[Peter Clinch]

Richard wrote:

> Shirley it's an (almost) worst case scenario

A factor 2[*] fall is *the* worst case scenario, and that's why it's
used as the test.

> protection (pitons, through which the rope is passed) periodically.

Point of order, m'lud: pitons (pegs) are very rare these days in rock
climbing, and not /that/ common in winter climbing. Protection more
typically takes the form of wedges or cams placed in cracks, and these
are linked to the rope by karabiners (clips that spring shut).
But pitons or wedges or cams can only be placed if there's anywhere to
put them: a blank wall doesn't allow anything.

> get to the length of the rope, and then fall, and every piton comes
> loose without stopping you -

If they slow you down a bit before they rip that may help, or just give
another jerk to rattle your body a bit... ;-/ Just because the rope
won't fail doesn't mean it ain't gonna hurt... :-(

Pete.

[*] distance fallen divided by length of rope between faller and anchor
IIRC. It doesn't have to be the whole rope length.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/

 

[Tony Raven]

Peter Clinch wrote:
>
> But pitons or wedges or cams can only be placed if there's anywhere to
> put them: a blank wall doesn't allow anything.
>

The days of taking the Black & Decker with you are gone then?

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

 

[Richard]

Peter Clinch wrote:
> Richard wrote:
>
>> Shirley it's an (almost) worst case scenario
>
>
> A factor 2[*] fall is *the* worst case scenario, and that's why it's
> used as the test.

I meant the (almost) worst case scenario for the /climber/; the WCS is
clearly the last anchor point failing. It is of course the WCS for
the /rope/.

>> protection (pitons, through which the rope is passed) periodically.
>
> Point of order, m'lud: pitons (pegs) are very rare these days in rock
> climbing, and not /that/ common in winter climbing.

I plead ignorance on the grounds of not being a climber but reading too
many accounts of early Himalayan expeditions, m'lud.

R.

 

[Richard]

Tony Raven wrote:
> Peter Clinch wrote:
>
>>
>> But pitons or wedges or cams can only be placed if there's anywhere to
>> put them: a blank wall doesn't allow anything.
>>
>
> The days of taking the Black & Decker with you are gone then?

How boring.

R.

 

[David Hansen]

On Mon, 10 Apr 2006 12:07:16 +0100 someone who may be Tom Crispin
<[email protected]> wrote this:-

>120 meters freefall, before arresting, is a hell of a drop, and
>velocity, without taking wind resistance into account, would be close
>to 50 m/s or 110mph, the speed of a freefall parachutist with arms and
>legs extended.

Indeed. As well as the possibility of the fixing coming out there is
the possibility of being snapped in half. Better odds than hitting
the ground though.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

 

[Clive George]

"David Hansen" <[email protected]> wrote in message
news:[email protected]...
> On Mon, 10 Apr 2006 12:07:16 +0100 someone who may be Tom Crispin
> <[email protected]> wrote this:-
>
>>120 meters freefall, before arresting, is a hell of a drop, and
>>velocity, without taking wind resistance into account, would be close
>>to 50 m/s or 110mph, the speed of a freefall parachutist with arms and
>>legs extended.
>
> Indeed. As well as the possibility of the fixing coming out there is
> the possibility of being snapped in half. Better odds than hitting
> the ground though.

Fortunately climbing rope is very stretchy, so won't snap you in half.
Static rope, as used for boats and caving is a rather different matter...

(however it is quite amusing watching people try to prussik on climbing
rope...)

cheers,
clive

 

[Peter Clinch]

Tony Raven wrote:

> The days of taking the Black & Decker with you are gone then?

A while since I've followed climbing's bleeding edge that closely, but
the ethics of pre-bolting routes made for debates that made cycle helmet
flame wars look positively benign and unusually interesting...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/

 

[Peter Clinch]

Clive George wrote:

> (however it is quite amusing watching people try to prussik on climbing
> rope...)

Makes it excellent for practice though: 3 feet for the space of 2! ;-)

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/

 

[Tony Raven]

Peter Clinch wrote:
> Tony Raven wrote:
>
>> The days of taking the Black & Decker with you are gone then?
>
> A while since I've followed climbing's bleeding edge that closely, but
> the ethics of pre-bolting routes made for debates that made cycle helmet
> flame wars look positively benign and unusually interesting...
>

Pre-bolting? Tsch. Bolt as you go! ;-)


--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

 

[Tom Crispin]

On Mon, 10 Apr 2006 14:25:45 +0100, David Hansen
<[email protected]> wrote:

>possibility of being snapped in half.

It's probably safer than you'd expect.

Assuming 5% elasticity in the rope, that is a 3m extension of a 60m
rope, deceleration would be just over 4g for 1.2 seconds. (If my
basic mathematics is correct.)

 

[Clive George]

"Peter Clinch" <[email protected]> wrote in message
news:[email protected]...
> Clive George wrote:
>
>> (however it is quite amusing watching people try to prussik on climbing
>> rope...)
>
> Makes it excellent for practice though: 3 feet for the space of 2! ;-)

How to prussik on dynamic rope:

Take up the slack. Coil it up beneath you. Continue taking up the slack and
coiling. Step from the top of the coil onto the top of the pitch.

cheers,
clive

 

[Peter Clinch]

Clive George wrote:

> How to prussik on dynamic rope:
>
> Take up the slack. Coil it up beneath you. Continue taking up the slack
> and coiling. Step from the top of the coil onto the top of the pitch.

It does give you a potentially useful edge for crevasse escape from
under an edge (as told to me by a pal who used to work for BAS).

Pull in the stretch as much as you can, kick back and let the stretch
pull you up over the lip.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/

 

[Peter Clinch]

Tom Crispin wrote:

> Assuming 5% elasticity in the rope, that is a 3m extension of a 60m
> rope, deceleration would be just over 4g for 1.2 seconds. (If my
> basic mathematics is correct.)

I think you'll do rather better than 5% elongation, and I'd also guess
that the time it would take a rope to stretch 3m would be rather less
than 1.2 seconds, so I think the final deceleration figure will need
some different basic assumptions. Not that I'm coming up with any
reliable ones myself, mind...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/

 

[Alan Braggins]

In article <[email protected]>, Peter Clinch wrote:
>Richard wrote:
>
>> Shirley it's an (almost) worst case scenario
>
>A factor 2[*] fall is *the* worst case scenario, and that's why it's
>used as the test.

It's the worst case for the rope. Worst case for the climbers is that
_none_ of your protection holds, and you, the rope, and the person
belaying you all fall further than the rope length.
(Obviously climbers try very hard for that not very to happen, since
if you know there is no chance of anything holding, you are better off
free climbing with no rope (or, more sensibly, doing something else).)

 

[Richard]

Peter Clinch wrote:
> Tom Crispin wrote:
>
>> Assuming 5% elasticity in the rope, that is a 3m extension of a 60m
>> rope, deceleration would be just over 4g for 1.2 seconds. (If my
>> basic mathematics is correct.)
>
>
> I think you'll do rather better than 5% elongation, and I'd also guess
> that the time it would take a rope to stretch 3m would be rather less
> than 1.2 seconds, so I think the final deceleration figure will need
> some different basic assumptions. Not that I'm coming up with any
> reliable ones myself, mind...

Nor me, but I do know that some climbing rope makes for excellent load
securing rope, because of its stretchiness, ease of knotting, and ease
of unknotting. (I was once in casual conversation with a safety
officer and he mentioned he'd just had to condemn umpteen metres of
climbing rope because there was no paper trail as to how old it was and
how many falls it had taken; he could let me have as much as I wanted,
provided it was cut into no more than 2m lengths.)

R.

 

[Tom Crispin]

On 10 Apr 2006 00:15:20 -0700, "David Martin"
<[email protected]> wrote:

>
>Tom Crispin wrote:
>> The London Cycle Campaign have online factsheets. This could be an
>> excellent starting point for our factsheet.
>
><much good advice snipped>
>
>Most of us here are quite literate and able to read through lots of
>documentation. This is not neccessarily the case for all parents, and
>many will lose interest just seeing a lot of text. I would be loathe to
>put too much wordage into a document (even though it is good wordage)
>but focus on the visual instead.
>
>For the equipment/bike choice/safe bike I'd suggest two pictures, one
>of a badly fitting bike and poorly dressed rider/insecure load and one
>of a properly equipped (no 'special' gear, just doing it right with the
>same clothing/luggage). The two pictures are contrasted with a series
>of bullet points. (helmet, bike size, lights, loose clothing, light
>colours, loose luggage, brakes/tyres)
>
>This would probably have to be done in landscape.
>
>More later.

1st Draft

Front Page

==========
CYCLING TO SCHOOL



[photo of a parent, with a todler in a handlebar carrier, accomanying
a young child to school (I know just the family!)]



==========

Inside page 1

==========

The government has highlighted its concern over increasing levels of
obesity in children. Cycling is a great way to combat this.

Increasingly schools are promoting cycling for children over 9 years
old, and National Standard cycle training is often part of the
curriculum. Once a child has completed an on-road National Standard
cycle training course you may like to consider them cycling to school
independently.



[Photo of two children cycling to school, on the road just outside a
school]



Facts:
- children will be more alert for the day ahead
- long term health benefits
- children are able to socialise with other children who live locally
and form connections within their community
- gives the children responsibility and independence
- reduced traffic around the school

==========

Inside page 2

==========

Cycle Training

[Photo of instructor on-road with children]

National Standard cycle training is the best way to prepare your child
for cycling to and from school. Good on-road courses will cover all
the following.
* maintenance - how to carry out a daily bike check
* road positioning - how to see and be seen
* traffic awareness - how to look all around including behind
* communication - getting eye contact with other road users
* making intentions clear - how to signal left and right
* cycle facilities - how and when to use on and off road cycle lanes
* security - how to secure a bike with a lock

Depending on local conditions you child may be offered further
training including some or all of the following:
* mini roundabouts - turning left, right and going ahead
* built roundabouts - how and when to use and when to walk across
* pedestrian lights - where to stop and when to move on
* junction lights - when to use and when to walk across
* cycling at night - extra care needed and using lights
* busy roads - how to use and how to cross

==========

Back Page

==========

The Right Bike

All your child needs to start cycling is a bike in good working order
and a strong lock.

There are several different types of bike on the market, and selecting
the best one for your child can be very confusing. The very cheapest
use poor components and and may not survive the rigours of childhood
cycling.

[Some advice of the different types of children's bikes, with
diagrams. Someone help, please]


Fitting the bike

The child should be able to stand astride the bike with both feet on
the ground and be able to touch the ground with the toes of one foot
when sitting on the seat. As with any bike you should make sure the
bike is in good working order and is fitted with a bell and
reflectors.


Clothing

If the weather is cold your child should dress warmly; simarlily in
the summer don’t forget to protect your child against the sun. It is
also a very good idea to wear high visibility clothing such as
reflective vests, armbands and leg straps. Cycle gloves protect the
hands and make using grip shift gears easier.

Some people choose to wear helmets. It is important for children to
understand that helmets do not make them invulnerable, they do not
prevent collisions and are only designed to withstand low speed
impacts. If you are choosing a helmet it should be neither too loose
nor too tight. Helmets should be replaced after an impact such as
being dropped, or if you have been in a collision and hit your head.

 

[David Hansen]

On Mon, 10 Apr 2006 14:58:20 +0100 someone who may be Peter Clinch
<[email protected]> wrote this:-

>I think you'll do rather better than 5% elongation, and I'd also guess
>that the time it would take a rope to stretch 3m would be rather less
>than 1.2 seconds, so I think the final deceleration figure will need
>some different basic assumptions. Not that I'm coming up with any
>reliable ones myself, mind...

If anyone wishes to try it out that is up to them.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

 

[Tom Crispin]

On Mon, 10 Apr 2006 14:58:20 +0100, Peter Clinch
<[email protected]> wrote:

>Tom Crispin wrote:
>
>> Assuming 5% elasticity in the rope, that is a 3m extension of a 60m
>> rope, deceleration would be just over 4g for 1.2 seconds. (If my
>> basic mathematics is correct.)
>
>I think you'll do rather better than 5% elongation, and I'd also guess
>that the time it would take a rope to stretch 3m would be rather less
>than 1.2 seconds, so I think the final deceleration figure will need
>some different basic assumptions. Not that I'm coming up with any
>reliable ones myself, mind...

I made a ten-fold error.

deceleration would be about 42g. The time taken to decelerate would
be 0.12 seconds.

At 10% elongation figures could be halved.

Unfortunately, the greater the elongation the greater the chance of
hitting the ground.

 

[Richard]

Peter Clinch wrote:
> Tom Crispin wrote:
>
>> Assuming 5% elasticity in the rope, that is a 3m extension of a 60m
>> rope, deceleration would be just over 4g for 1.2 seconds. (If my
>> basic mathematics is correct.)
>
>
> I think you'll do rather better than 5% elongation, and I'd also guess
> that the time it would take a rope to stretch 3m would be rather less
> than 1.2 seconds,

Here we go:

http://biomech.me.unr.edu/****/abstracts/rope_drop.htm

R.

 

[Simon Brooke]

in message <[email protected]>, Richard
('[email protected]') wrote:

> (I was once in casual conversation with a safety
> officer and he mentioned he'd just had to condemn umpteen metres of
> climbing rope because there was no paper trail as to how old it was and
> how many falls it had taken; he could let me have as much as I wanted,
> provided it was cut into no more than 2m lengths.)

That's vandalism. Old climbing rope makes very good anchor warp for
multihulls.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; making jokes about dyslexia isn't big, it isn't clever and
;; it isn't furry.