18 people attended and the group started with a basic "refresher" practice lift on a 20 metre cliff near the Boars Head, Katoomba. A Larkin Frame was used and a simple lower of litter attendant with litter, retrieval of patient and lift followed by a hauling operation to retrieve the litter attendant and patient. A 4:1 haul ratio was used by a team of 5 haulers. Two people were stationed on the cliff edge to facilitate communications (no radios used on this lift) and to help bring the loaded litter over the cliff edge at the top of the haul.
A more ambitious task was then set and executed with an extended
vertical extraction from the deep narrow crevasse beneath the
Boars Head followed by a Tyrollean Traverse using a span line
arrangement for bringing the patient and attendant back to the
cliff top. The scenario was of a patient with a broken lower leg
at the base of the first abseil of the crevasse. A scout was sent
ahead to evaluate the line of the evacuation and possible use of
the tyrollean. The scout evaluated the patient and then provided
information to the rescue team at the cliff top. The block at the
top of the vertical lift was small and devoid of anchors so in
this situation it was decided to use that area as a redirection
for the haul which was conducted from the main cliff top. The
block was then rigged to provide the lower anchor for the
tyrollean traverse span lines for the second phase of the
evacuation. The anchors for both positions (top and block) were
provided by equalised trees, boulders and removable protection.
The block anchors were extended to the top of the block and were
stabilised (sideways) to prevent the attachment point from rolling
off the block.
The vertical lift was straightforward although extra friction was
noted by the haul team due to the extra redirectional pulleys on
the block. Although the rope was kept clear of rubbing on the
rock, the extra friction caused by direction changes and from
deviations around pulleys was considerable. The belay rope path
was kept very closely aligned to the path of the rescue line to
minimise rolling or shock loading in the event of any failure of
the rescue line.
Once on top of the block the patient (in litter) and litter
attendant were attached to the tyrollean and were hauled at an
angle of approximately 20 degrees (rising) to the top of the main
cliff over a horizontal distance of approx 55 metres. Double span
lines (11mm static) were used to increase the safety factor and
tension was kept low (see notes elsewhere on span line tension) to
keep "force magnification" within acceptable limits. A double
pulley was used to attach the patient and attendant to the span
lines. A second double pulley was used to provide a backup pulley
in order to maintain two points of attachment to the span lines.
The attendant hung slightly below the patient which helped in
getting the patient off the block and over the top cliff edge with
minimum bumping. It was decided to have both the patient and the
attendant on the system to give the group a high level of
difficulty for the task - we ammended the scenario to include a
situation where the patient may have been having breathing
difficulty and an attendant was required to maintain an airway. If
it was not essential for an attendant to travel with a patient in
an evacuation a greater safety margin becomes possible with just
one person on the tyrollean at a time.
A "soft" litter (SKED type) was used for this scenario which was
excellent for the narrow confined nature of the vertical crevasse
for the first lift but became very uncomfortable for the patient
on the tyrollean. A better option may have been to use the SKED
for the vertical section and to have transferred the patient to a
stokes for the remainder.
The haul team used a 5:1 ratio for the vertical lift due to the
anticipated additional friction provided by the major direction
changes on the block. This was changed to a 4:1 for the
tyrollean.
Due to the relatively slack span lines (to keep magnification
forces low) the litter and attendant ended up below cliff top
height on arrival at the top of the haul. Four people were
positioned at the edge to help bring the litter over the edge.
This worked well.
To keep the span lines as high as possible the Larkin Frame was
used a a static tripod (in "laid right back" mode") for the span
lines. The head of the tripod was tied off sideways (at approx 90
and 270 degrees) to help minimise any tendency of sideways
movement. The haul lines did not go through the head of the
tripod. In addition to the haul line and a second belay line to
the cliff top (as per our standard methods) the patient and
attendant were also belayed "uphill" from the block (gri gri) so
that in the unlikely event of a span line failure the belay ropes
would provide a "suspended" belay. The lower belay from the block
was carefully managed so as to never become tight against the haul
team which could produce unacceptable loads on the rear and block
anchors.
Removable redirections were used below the block to keep the haul
path clear of obstacles and constrictions. Radios (chest mounted
UHF) were used for communications on this task.
The advanced task took about four hours from initial planning to
completion which included some time taken for explanation of
various points to the group.
The group comprised a wide variety of members (with varying skills
and experience), a number of newcomers and two members of the
Police Rescue Service. The day was a great success and was a good
demonstration of close team work from a diverse group.
Many thanks to all those who contributed time and loaned gear.