Page 60 - Theory and Design of Air Cushion Craft

44 Introduction to hovercraft

there has been a gap in the payload capacity range between 10 and 50 tonnes.
Developments with the BHC API.88 and the ABS M10 have resulted in capable util-
ity craft which can also be applied to slightly different missions. The GRP structure
M10 is particularly suited to missions requiring stealth, such as anti-piracy patrols,
while the API.88-400 fills the gap in payload capacity.
In the smaller utility range, craft from Griffon and Slingsby deliver payload capac-
ity between 1 and 5 tonnes suitable for amphibious coastguard patrol, which has
proven effective in a number of European countries. The high speed, good seakeeping
qualities and spacious deck and cabin areas suggest that SES, particularly the air
cushion catamaran, could be used as patrol boats, anti-submarine vessels to join with
PHM, and also as air cushion guided missile vessels. During the 1990s Norway has
provided the technology leadership with the development of its fleet of MCM SES,
followed by Fast Attack SES.
Following the end of the 'Cold War' in 1990, the conflict in the Arabian Gulf, and
later the Bosnian conflict, many countries have experienced a significant shift in the
missions which their military forces were designed to meet. Rapid deployment to a
remote conflict feature significantly. Over the shore deployment, often coupled with
the maintenance of a force of arms close by for an extended period, are also impor-
tant requirements. This is mostly met by the delivery of aircraft carriers and amphibi-
ous assault ships. The SES may in the medium term offer an alternative, or extension
to this strategy. Some marine weapons systems, such as ship-to-ship guided missiles,
ship-to-air guided missiles, helicopters and antisubmarine weapons may be distrib-
uted into an integrated Sea Action Group (SAG) using a number of smaller fast ves-
sels, rather than a single large unit such as present aircraft carriers. This could lead to
a revision of the surface fleet into a larger number of smaller units.

Civil ferry and utility applications
SES can be used as passenger craft on inland rivers, estuaries, river mouths and
coastal areas. SES have proven to be very successful in the payload range between 60
and about 400 passengers for inshore and coastal routes. Development of vehicle car-
rying craft remains a challenge, awaiting market demand for craft with service speeds
above 50 knots.
ACV can be used as passenger ferries, logistics vehicles or pleasure craft, operating
on shallow water, beaches, swamps and other regions which conventional ships find it
difficult to have access to. Craft with pay loads up to the equivalent of 100 passengers
have matured in the 1990s, and have found a widening market as buildup of operat-
ing experience has encouraged new operators. Utility operations prove to some extent
to be niche applications, since the requirement often cannot be fulfilled by any other
vehicle, and so past experience is not available to the ACV designer. This track record
is slowly being built by the different ACV operations themselves.

Oil field applications

It is most convenient to use ACV as air cushion platforms in onshore and coastal
regions, particularly where the ground is swampy or sensitive tundra. ACV platforms