The Leguan Ferry

Krauss-Maffei Wegmann

Category: Mobile Bridges

1.Components

The LEGUAN ferry consists of a LEGUAN bridge, a ramp set and pontoons.

LEGUAN ferry MLC 30
LEGUAN Ferry MLC 30

LEGUAN ferry MLC 70
LEGUAN Ferry MLC 70

Some of the pontoons have a built-in diesel engine and water pumpjet. A MLC 30 ferry comprises of 6 pontoons (2 powered), while a MLC 70 ferry has 12 pontoons (4 powered). The ferry set also has inflatable buoyancy elements and cover plates for the unpowered pontoons to prevent filling with water.

The set additionally includes bilge pumps and lanterns.

Buoyancy ElementsCover Plates

A connecting joint is used to connect more than one ferry together to construct a floating bridge. All the components are transported on standard trucks.

2.Construction

The pontoons are lowered onto the water, either by crane or by a special launching mechanism on the truck.

Truck with launching mechanism
Truck with launching mechanism

The pontoons are manually coupled together on the water, stern to stern.The LEGUAN bridge is then laid (by a LEGUAN bridge layer or a crane) on top of the pontoons.

Laying of the LEGUAN bridge (by LEGUAN-truck or LEGUAN-tank)
Laying of the LEGUAN bridge (by LEGUAN-truck or LEGUAN-tank)

The bridge is secured to the pontoons by means of flip bolts on the pontoon gunwales.

Securing the bridge on the pontoons
Securing the bridge on the pontoons

The ramp set (4 ramps) is then mounted in place by crane (transportation vehicle).

Mounting-in-place of the ramp set
Mounting-in-place of the ramp set

Each ramp weighs 1,200 kg. Two ramps are fitted to either end of the LEGUAN bridge. The ramps are individually controlled using the hydraulic system on the inboard diesel engines.

Where the ferry has to operate in fast-flowing waters, or there are high waves, the pontoons are equipped with the above-shown safety buoyancy elements (air-filled by a compressor, which is driven by the diesel engine) and aluminium covers.

The connecting joint can link two or more ferries together to form a floating bridge. The floating bridge has to be anchored according to the water conditions.


3.Operation

The LEGUAN ferry is operated by a ferry commander and by one person per engine, meaning that an MLC 30 ferry has a crew of three persons, and an MLC 70 ferry a crew of five persons.

Operating the ferry
Operating the ferry

The crew control the diesel engine, which powers the pumpjet. The crew also control the hydraulic ramps, the compressor, the bilge pumps and the lanterns.

The ferry commander directs the crew by means of visible signs or by radio. The ferry is manoeuvred by altering the speed of the engines and/or the thrust direction of the pumpjets.

Commander's controls
Commander's controls

The ferry is very easy to manoeuvre and is normally controlled simply by reducing the speed on one or two engines.

The ferry can shuttle across the gap with the pontoons arranged parallel to the water current or at an angle of 90 degrees to it.

The payload is easily brought onboard via the ramps. During loading/unloading, the ramps are pressed down onto the shore to keep the ferry in position. The waterjets are also then used to keep the ferry stable in the right position.

Loading and unloading of the ferry
Loading and unloading of the ferry

As the ferry has ramps at both ends, the vehicles can be driven on and off, making the loading/unloading operation very quick and also safe.

4.Technical Data

  • Capacity of superstructure (bridge and ramps):MLC 70
  • Width of trackway:4 m
  • Capacity of ferry with 6 pontoons:MLC 30
  • Capacity of ferry with 12 pontoons:MLC 70
  • Speed with max. load:7 knots
  • Total length of ferry (loading length):35 m
  • Total width of ferry:18 m
  • Height of empty ferry on water: 2 m
  • Draught of empty ferry:0.3 m
  • Draught of max. loaded ferry:0.8 m
  • Water jet:Schottel Pump Jet SPJ 20 II
  • Engine:Diesel (MAN D0834) inboard 115 kW sweet-water-cooled, closed-circulation system with fan-cooled radiator and dry exhaust
  • Hydraulic system:Variable pump, max 200 bar 100 l/min
  • Pontoon measurements:L = 9 m W = 2,2 m H = 1,2 m
  • Pontoon dry weight, powered3,700 kg
  • Pontoon weight, unpowered1,600 kg
  • Ramp measurements:L = 5 m W =2 m H = 0,6 m
  • Ramp weight:1,200 kg, Ramp set = 4,800 kg