Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Theoretical Study of Ditch-Crossing Movement of Hovercraft
Haipeng Zhang, Jingfeng Fan, Genquan Zhang, Song Gao
Marine Design & Research Institute of China,Shanghai, CHINA

ABSTRACT

movement is established to study the ditch-crossing capability of thehovercraft, and the responding program is developed. The hovercraft
has a displacement of 23T, a length of 12m and a width of 7m. It adopts
a single-fingered apron with a height of 0.7m, a full load displacement
and air cushion pressure of 2500Pa, as shown in Fig. 1.

Hovercraft is a kind of high speed vehicle which is close to the support
surface. It has the performance of fast speed, good amphibious property
and strong environmental adaptability. When the hovercraft is used forpolar transportation or beach landing, it often encounters obstacles in
the form of crevasses and trenches. Therefore, it is necessary to study
the ditch-crossing capacity of all-cushion hovercraft which is an
important index to the amphibious performance. Aiming at a hovercraftof the national key research and development program, a mathematicalmodel for ditch-crossing movement is established and thecorresponding calculation program is developed to analyze the ditchcrossing ability of the hovercraft, which is of great value to evaluate theobstacle crossing performance of the hovercraft..

KEY WORDS: Hovercraft; mathematical model; Ditch-crossing.
INTRODUCTION

Fig.1 The picture of Hovercraft

Hovercraft is a kind of high-speed vehicle gliding close to the support
surface (such as ground, water and ice) with some performances
including high speed, good amphibious property and strong
environmental adaptability, which holds a obvious advantage in thoseareas such as military, rescue, ice breaking and mine clearance,
especially suitable for the landing operations and polar environment as
land transport tools [Yun, Ma], and thus it draws the world’s strong
attention. The working principle of the hovercraft is to use high-power
fan to quickly press a large amount of air into the bottom of the hull toform a dynamic air cushion between the bottom of the hull and thewater surface in order to make the hull completely out of the water. At
the same time, a flexible apron is used to seal the air cushion around thebottom of the hull to increase the ability of fly high, wash beach andjump over obstacles.
When the hovercraft is used for polar transportation or beach landing, it
often encounters complex terrain environment, among which the mostcommon obstacle is ditches such as ice crack in polar environment[Wang] and entrenchments in battle field. Therefore, the capacity for
ditch-crossing is an important indicator to determine the amphibious
performance of the hovercraft. At present, Murakami and others havestudied the movement performance of hovercraft on the ice surface, butthere are few studies on the ditch-crossing ability of hovercraft.
In this paper, aiming at a hovercraft of the national key research &development program, a mathematical model of ditch-crossing

MATHEMATICAL MODEL OF HOVERCRAFT CROSSING
DITCH
When hovercraft crossing the ditch in the polar region, it usually sails
in a straight line without drift angle and roll angle, so it only needs toconsider the 3-DOFs motion mathematical model of surging, heave andpitch. Fig.2 shows the moving coordinate system oxy fixed on the hull,with the origin of coordinates located at the center of gravity. The x
axis points to the bow, the y axis points to the starboard side, and the zaxis points to the bottom..

Fig.2 Moving coordinate system of hovercraft when crossing the ditch3802