Page 56 - Theory and Design of Air Cushion Craft

40 Introduction to hovercraft

was by propellers. Passenger capacity was 264. This craft performed very well, reach-
ing 42 knots in light weather, and was eventually placed in service between Harstad
and Tromso. Brodrene Aa followed this success with the construction of several sim-
ilar SES with higher passenger capacity, powered by water jets, which have been oper-
ated at many locations in the world on charter. Most continue in regular work today.
Other builders in Norway developed their own designs, initially for ferries, as a
higher speed variant to their main product, the high speed catamaran. In 1986 the
Norwegian Navy began a programme to develop an SES Mine counter measures ves-
sel, again encouraged by the earlier US Navy Programme. After keen competition, a
consortium of companies in Mandal, Southern Norway won the contract. Cirrus pro-
vided technical expertise for the cushion system. A total of nine craft were built and
are in operation with the Royal Norwegian Navy. The commercial SES product devel-
opment started by Brodrene Aa was taken over by Ulstein Industries, who have in
turn licenced their design to a shipyard in Western Australia.
The MCMH programme is now succeeded by a similar development programme
for an SES High Speed Coastal Patrol Vessel. The construction programme for this
class will begin with a prototype, and continue with further vessels into the first
decade of the next century. Due to the increased performance of catamarans during
the 1980s, SES have not become as widespread as passenger ferries, as had been
expected. The technology will need to take the next advance in size to high speed
coastal cargo vessels before moving forward commercially. Japan leads this develop-
ment at present.
Over this same period builders in Holland, Germany, France and Italy all studied the
SES, and produced design proposals. In Germany, a prototype similar in size to the
Br0drene Aa SES, the MEKAT, was built by Blohm and Voss for the Navy. In Holland
Royal Schelde built a 22m prototype for test, which was put in service on the Solent for
a summer. Royal Schelde have since progressed to the construction of large car-carry-
ing catamarans. At the end of the 80s, proposals were made for larger car-carrying
SEC, and in Italy, a shipyard, SEC, designed and obtained orders for 4 craft suitable
for 750 passengers and 120 cars. Unfortunately this SEC, incorporating a steel hull,
was not completed, as the operator who had ordered the SES went into liquidation.
Since 1990 there has been a national development programme in Japan to develop
high speed short sea cargo vessels. The first SES prototype is a 70 metre vessel with a
speed of 42 knots, which is itself a scale model of the planned cargo SES. Power is
from industrial gas turbines, and propulsion by water jets. Trial results have so far
been very encouraging.
In Korea, SES and ACVs have been built for many years. In the early 80s Korea
Tacoma Marine Industries built a number of SES similar in size to the Hovermarine
HM2 series and 5 series. More recently Semo Shipbuilders have developed a craft sim-
ilar in size to the Brodrene Aa/Ulstein SES. Several such craft are in service. Attention
is now towards larger car-carrying SES, which are under development. SES develop-
ment is now also active in Western Australia where two craft of 300 passenger class
have been completed for ferry services, based on Ulstein SES designs.
In the UK, a number of API-88 amphibious ACVs were built during the 80s, for
both ferry and utility roles. The most recent craft have been a coastal passenger/cargo
craft for the White Sea Coast in Russia and the development of the API-88 400 class
for the Canadian Coastguard. There may be up to 4 of these craft in service. An open