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SELF-RIGHTING BOAT DESIGN 41

SELF-RIGHTING BOAT DESIGN

Hakan Akyıldız, Cemre Şimşek
Istanbul Technical University | akyildiz@itu.edu.tr

ABSTRACT

The stability behavior of small craft is of great importance at very high angles of heel, up to the
completely inverted condition. The fundamentals of stability in the design of yachts and other small craft
is considered, and the significance of our current understanding is reviewed based on static stability
analysis.
There are three main self-righting methods examined in this study. These are; inherent self-righting
method, inflatable bag method and moveable ballast method. All of them have their advantages and
disadvantages. Inflatable bag is easy to apply and maintenance, but there are very small area of
applicability and does not ensure safety of the crew. Moveable ballast method practically applicable only
for small craft and maintenance of mechanical components is hard. On the other hand, it can be designed
to be self-operating system and fitted to small open boats where buoyant superstructure is not a feasible
option. Although designing inherently self-righting craft is challenging due to the difficulty of weight
distribution’s uncertainty during the design process, it is the best option for any self-righting vessel.

Keywords: Self-Righting methods, Self-Righting stability, Capsizing.

1. Introduction

Regardless of the type of floating structure that is being designed, one of the designer’s main
tasks is to ensure the safety and seaworthiness of the structure, a prime consideration being the
safety against capsizing. Despite recent advances in ship hydrodynamics, the possibility with a
good measure of confidence, and in fact relatively little attention has been paid to the
mechanism of capsizing.

The solution of the ship capsizing problem is one of the major challenges that scientist and
naval architects have to meet. The problem is as old as shipbuilding itself. It concerns ship
operators and designers and has preoccupied researchers’ attention for many years. Capsize
disasters are so painful, not only because of material losses, but primarily because they take
human lives.

It is not strange, therefore, that the matter is raised and discussed so frequently. It is amazing,
however, how little progress is being made despite the considerable amount of research that has
been carried out in this field worldwide.

At present, there is no scientifically based stability safety criterion, and there is no mathematical
model of ship capsizing in the general case of operation in extreme waves.

Two predominant approaches to the ship capsizing problem can be observed at present. One of
them is based on the classical assessment of stability safety by analysis of the righting moment

Sayı 6, 2016 GiDB|DERGi