Feature 3 | Helo/AircrAft HAndling
Tie-down study helps reduce cost of
prized asset
With the new Queen Elizabeth (QE) class aircraft carrier being a hugely
complex machine, tie-down points for aircraft onboard may appear to be
relatively simple pieces of equipment. However, as the anchor points for
the valuable JSF aircraft, the importance of tie-down points on the QE class
cannot be underestimated.
T
ie-down points are generally
the accepted means of securing
aircraft to the deck of an aircraft
carrier, enabling a chain with a lashing
to be passed between the aircraft to
an anchor on the deck. Compared to
previous vessels such as the Royal Navy’s
Invincible class, the design of the QE
class incorporates a large number of
tie-down points.
At a cost of £9 million (US$14.5
million), the points are a significant
investment, so Frazer-Nash Consultancy
was invited to assess the potential for
cost savings, whilst achieving the full
functionality required – something that
existing ‘off the shelf ’ products could
not do.
The original designs for the QE class
allowed for a total of 6600 tie-down
points based on existing ‘off the shelf ’ Adopting a systems engineering approach, frazer-nash set out to investigate whether
designs. Adopting a systems engineering changes could be made to the design of aircraft tie-down points to reduce their number.
approach, Frazer-Nash and the carrier
design team set out to investigate whether
changes could be made to the design to learning points therefore, Frazer-Nash two lashing hooks per tie-down, the team
reduce this total number, cut the cost set the following parameters ahead of achieved a 34% reduction in the total
of installing the points and maintaining further design work: number of points required.
them, and/or limit the need to repair or
•
tie-down point must accept MC2 The second major area of consideration
refit the points. lashing hook; was the cost of installing the tie-down
The first stage in Frazer-Nash’s
•
minimum 30-year life without repair points – estimated to originally be around
approach was to assess lessons learned or refit; 30% of the total part cost. Tie-down
from previous experience. One lesson,
•
no moving parts; points are welded into gaps cut into the
for example, related to the use of moving
•
simple robust installation; deck and therefore need to act as an
parts. The tie-down points fitted on the
•
reduce installation labour requirements integral part of the deck.
Invincible class carriers contain moving compared to the Invincible class; and A number of cost-reducing solutions
parts and are prone to collecting debris.
•
approved by Lloyd’s Register. were identified here, including
In turn, the moving parts are applying the weld preparation to the
susceptible to corrosion, damage and The first consideration for the team tie-down pot rather than the deck itself,
wear, with an estimated 15% of the was a means of reducing the total number thereby enabling machine work to be
points needing to be replaced during the of tie-down points installed, through a carried out in a factory rather than
vessels’ lifetime. new distribution pattern on the deck. on site. The team also optimised the
Acknowledging this and other key By adopting a new pattern and applying design of the tie-down point to ensure
20 Warship Technology March 2010
WT_Mar-2010_p20-22-23.indd 20 24/02/2010 10:54:23
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44