Nepal Academy of Science and Technology (NAST)

Natural Force Ferry Boat System (NFF Boat)

Background

Three dimensional view of NFF

A perspective view of the NFF system

Nepalese people living in hilly regions are divided/cut off from the outer world by rivers and streams, isolating them from the development scenario. Due to this isolation, the rural population in Nepal constantly faces socio-culture, economical, and development problems. Even the basic needs such as education, health care, and basic supplies and commodities are inaccessible for the rural inhabitants.

The traditional means of river crossings are:

-	Foot-trail Suspension Bridges
-	Ferry Boats
-	Twins

Natural Force Ferry Boat System

A natural force ferry boat system consisting of a boat, connected to the main cable running over and across the river via a towing post and cable ending in pulley, is used to cross the river using the water current energy of the same river as the prime driving force. The main cable is fixed at both ends of the river banks at the anchorage blocks. The towing post and cable maintains stability and balance of the NFF. The rudder block is fixed at the back end of the boat. The angle of the rudder blade facing the water current determines the speed of the boat.

Operating Principle

The angle of inclination (attack angle) of the river current q (theta) to the fin of the boat determines the speed
of the boat. The force diagram on the fin of the boat can be shown as follows:

where: F - Hydrodynamic forces; F L - Lift force
F D - Drag force; q - Attack angle can be adjusted from 0 to 90°

The greater the angle of inclination q (attack angle) the greater the speed of the NFF boat. When angle q is 0° the speed is 0 and when angle q increases the lift force FL increases and the speed also increases.

Description of the Natural Force Ferry Boat System

NFF fibre glass reinforced plastic boat consists of the following components:

-	Boat - fibre glass reinforced plastic boat
-	Rudder - metallic rudder fixed at the back end of the boat
-	Towing post - metallic structure fixed inside the boat
-	Main cable - cable running over across the river fixed at the anchorage blocks
-	Anchorage blocks - construction blocks to fix the main cable to the river banks

Objective of the Project

-	The main objective of the invention is to design, construct and use a boat which operates on water (current) energy of the rivers and the streams to cross the river.
-	To construct an improved and modified version of the NFF to meet the needs of the local people not only for the transportation of people but also for carribale amount of goods and commodities.

The boat can be made from other materials - wood and wood-based materials usable for the construction of
boats. The first NFF models used for testing were all made of wood. The boat can also be made from plastic
and polymerbased materials usable for the fabrication of boats.

Normal Design Parameters

Length of the boat	5 metres
Breadth of the boat	2.2 metres
Height of the boat	0.8 metres
Capacity of the boat	10 persons plus 100 kgs of goods
River velocity	between 1-2.5 m/s
Water depth of the river	50 cm (minimum)


Traditional river crossing technologies twin system		Traditional boat		Natural force ferry boat