Design of a Wind Propelled Planning Hull Craft for Shallow Water Operation

Abstract

During recent flash floods, Sri Lanka Navy rescue teams met with many circumstances where they could not use their Dinghies even with a short tail Out Board Motors (OBM) due to submerged obstacles at unprecedented depths. Therefore, designing a planing craft with rescue capability deemed a national necessity. This study explains the designing of a wind powered planing hull craft to operate in shallow waters during natural calamities like flood situations to move where stagnant water masses with uncertainly small depths. A speed boat with performance such as gaining top speed, achieving acceleration timing, turning characteristics, course keeping ability at top speeds, etc. are quite challenging which measure the overall performance of the boat. Preliminary analysis on the issue was made by the naval engineers who were attached to Sri Lanka Navy (SLN), where the case study was done collecting data after series of visits to flood affected areas. Size of the common alleyways in flood affected areas and their general flood height and the depths were calculated and hence size of the required boat with maximum allowable draft has been determined. Since the lesser capabilities of the SLN to finish a hull with required hydrostatic data seems costly a hull with required features determined and purchased to match with a suitable engine and a wind propeller with a suitable steering and protection mechanisms. Therefore, the purpose of this exploration was defined, then researched and designed a light weight flat bottom Fiberglass hull craft propelled by air for carrying out rescue missions during floods. Finally, subsequent study was conducted of hydrostatic and hydrodynamic forces, position of centre of gravity (CG), engine matching and propeller matching to the hull. The newly designed airboat is distinctive, and it can be operated at a wide range of both steady and moving waters.