Lake Pontchartrain & Adverse Weather Conditions

Waves

Lake Pontchartrain is an oval shaped relatively very shallow lake with the longest distance of 36 miles in an East/West direction, and 24 miles the widest distance in a North/West direction. The East side of the Causeway has a relatively uniform depth of 15 to 16 feet from near the coastline, while on the West side of the Causeway the Lake has a uniform depth of 13 to 14 feet from near the coastline.

Waves are divided into two categories; swell and wind waves. Swell waves can be very high waves with long wave length (period), generated by wind fields far away, and travel long distances over deep water. Swell waves are not, and will not occur in Lake Pontchartrain. Wind waves are generated and influenced by the local wind field. Wind waves are relatively short and steep, and are often both irregular and directional. These waves are also referred to as short-crested. Wind waves are the result of wind on the surface of the water. Wave height, wave length, propagation, direction and duration of the wave field at each location depend on the following:

1.Wind field (speed, direction and duration)
2.Fetch of the wind field (meteorological fetch or the water area (geographical fetch)
3.Water depth over the wave generation area.

Drawing from the above paragraph it is clearly indicated that the waves in Lake Pontchartrain are relatively low, short and steep; evident by the white caps during strong winds. This wave phenomenon is the direct result of "shoaling" and "bottom friction". Shoaling is the deformation of waves which starts when the water depth is less than half the wave length. Bottom friction causes energy dissipation, thereby resulting in wave height reduction when water depth is shallow. For these reasons, the height of the waves in Lake Pontchartrain will never be more than approximately 4 to 5 feet, and wave length (from top to top) not more than 20 feet during strong winds.

Comparatively, the ferry Pontchartrain Express 1 has a length of 81 feet and a width of 24 feet, resulting in no pitching and/or rolling while crossing the Lake. Sea sickness due to vessel motion will be highly unlikely. The vessel is designed with foils (wings) connected to the port and starboard hulls which lift the vessel and provides a smooth ride over waves (planing). The foils are comparable to wings on the airplanes, and act as stabilizers.

Wind

As there is always a possibility for strong winds, like an airplane, winds will only affect the speed and course of the vessel. Captains are trained and experienced in correcting the course during strong winds. Delays due to strong winds will be minimal.

Fog and Reduced Visibility

During Spring and Fall, and occasionally Winter, fog will be created and visibility will be impaired. The vessel is equipped with two "state of the art" radars, detecting all objects from large to small around the vessel to selectable distances up to 24 miles. Captains are trained and have experience interpreting any object on the radar screen. In addition to the radars, there will be an auxiliary look-out to assist the Captain on the bridge. During dense fog, when nearby objects are detected the Captain will reduce the speed of the vessel, and make sure the vessel can be stopped immediately to avoid contact with other objects. Furthermore, the vessel will sound a fog horn to alert other craft that the ferry is underway, and possible course changes are needed - all in accordance with good seamanship.

The design of the Pontchartrain Express 1 allows an immediate stop when the throttle is placed from cruising speed to full astern (rear); the stopping distance through the water is less than one ship length. The increased resistances of the water when the vessel reduces speed and the foils (wings) no longer lifting the vessel, are the main reasons for the short stopping distance.

Expected delays due to fog will be minimal.