Engineers page

The AV Tiger 12 hovercraft is manufactured from welded marine aluminium, welded to form a rigid box structure with 3 main compartments: *Crew and passenger accommodation. *Fan bay and drive. *Engine Compartment. The primary Hovercraft structure comprises buoyancy tanks, fore and aft shear walls and engine and fan mounting structures. The flexible Hovercraft skirt is attached as the secondary structure which is outboard of the primary structure and contains the lift engines and lifts fans. Additional buoyancy is provided by a six compartment outer hypalon/nylon inflated ring. The lower mid skirt is inflated by fan pressure and a bottom fingered skirt transfers the lift pressure to the ground.

The Hovercraft forward propulsion is provided by the 8 cylinder petrol engine and is connected to the upper propeller shaft by a toothed driving belt. Thrust is provided by a fixed pitch, four bladed propeller in a ducted enclosure and the lift force by an enclosed centrifugal lift fan.

The slipstream from the propeller passes over five rudders for directional control. Its noise level is approximately 62 db making it one of the quietest hovercraft to date and thus suitable for work in any sensitive area. The engine drives the centrifugal fan and supplies air to provide ventilation for the passenger cabin.

The AV Tiger 12 in civil passenger configurations can seat up to 10 passengers. The first AV Tiger 12 began operating in 1975 in the UK, Canada, America & Nigeria. It was originally designed to carry 12 persons i. e., 2 crew and 10 passengers but the number of seats is varied depending on use.

The Hovercraft cabin contains seating for 8 passengers and two pilots and is entered by port and starboard doors at the rear of the cabin. The port door at the rear end doubles as an emergency exit. Hand baggage racks are under the seats. The control cabin is at the forward end of the passenger cabin. The passenger cabin is heated by conventional heaters. The interior of the cabin has been refinished in fire retardant materials and two hand held fire extinguishers have been added including updating of the fire detection system.

Individual seats are provided for each person on board. Life Jackets are provided for each person and additional equipment such as flares and anchors are carried. There are both electrical and manual bilge pumps. 2 throw out life rings are fitted and there is a first aid kit and multi signalling equipment.

There are warning and information stickers around the craft to mark specific areas or items. The passenger cabin emergency exit is clearly marked and easily accessed. Anti slip surfaces have been applied to the walkways and treads and industrial spec safety steps are used for access into the craft.

There is a safety net to prevent accidental access to the propulsion system by persons or debris.  A radar installation and AIS is provided for collision avoidance and in conjunction with the compass as a navigational aid.

The gasoline fuel system comprises of a stainless steel tank housed within its own sealed compartment. It has 2 separated external ventilation systems, internal anti swilling and anti combustible gas inserts and an external filling point. The fuel lines are stainless steel within the construction and run at low pressure with auto pump shut off and an additional manual fuel tap. The Hovercraft fuel system is fitted with manual shut off and one way valves, fuel booster pumps and filters with water separators.

The engine bay is separately vented by a fan extraction point. All electrical switch gear and relays are housed within spark proof boxes and away from ignition risk areas. Fuel splash guards are fitted to the exhausts. The engine itself has spark arrestor exhausts and uses a PCV recirculation to reduce any oil vapours emitted from the unit. The craft has anti spillage or discharge units to prevent contamination into the marine environment.

The Hovercrafts engine bay is equipped with fire detection and double discharge fire suppression systems. 2 Independent Fire detection and suppression systems using Zero 360 gas injection (Halon replacement) are fitted. Both main and reserve systems are electrically independent and have current test certification portable, hand operated extinguishers are also carried in the rear and front of the passenger cabin.

The Hovercraft Tiger 12 electrical system is powered by one engine driven generator, with an emergency services drawing power from an emergency battery. The entire electrical system is protected by aircraft type circuit breakers that act as the switches at the pilot position. The pilot also has an independent fuse array and a total shutdown switch.

The Hovercraft safety equipment comprises GPS Chart Plotter, Class A AIS, Sea Marshall Man Overboard System, Auto Compass, Wind Display, Marine Band Radio, Radar,  Navigation and rescue search lights are standard fittings, first aid chest, signalling light, red parachute flares, floating line and quoits, fire axes, torches, knives, 12 person liferaft, infants life jackets, crew life jackets and side panel stowed life jackets for each passenger. Two lifebuoys are provided, one by each of the passenger doors. The life raft is capable of carrying all passengers and crew members.