International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 6

Number 1

March 2012

143

1 INTRODUCTION

Although the situation has improved somewhat re-

cently, a series of collisions have occurred in some

Japanese sea routes between hydrofoil-type super

high-speed vessels (hereafter “HF vessels”; Fig. 1)

and large marine life and continue to concern

transport officials and other relevant peoples to this

issue. These collisions are often the target of marine

accident inquiries that examine the responsible fac-

tors, and it would be accurate to state that in most

instances, the collisions involve cetaceans (Fig. 2).

Thus, such collisions not only negatively impact safe

navigation, but also represent a risk to the survival

of cetaceans.

Figure 1. Hydrofoil type of high-speed vessel, which are used

for important high-speed sea routes linking remote islands with

the Japanese mainland. (Photograph by H. Kato)

Figure 2. Sperm whale, a whale species with a high collision

risk with hydrofoil-type super high-speed vessels. Their popu-

lation in the waters around Japan has increased in recent years.

(Photograph by H. Kato)

Towards Safer Navigation of Hydrofoils:

Avoiding Sudden Collisions with Cetaceans

H. Kato, H. Yamada, K. Shakata, A. Odagawa, R. Kagami & Y. Yonehara

Tokyo University of Marin Science and Technology (TUMSAT), Tokyo, Japan

M. Terada & K. Sakuma

KHI JPS Co., Ltd., Kobe, Japan

H. Mori & I. Tanaka

Kawasaki Heavy Industries Ltd., Kobe, Japan

H. Sugioka & M. Kyo

Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan

ABSTRACT: Recently, sudden collisions between large cetaceans and high-speed hydrofoils have become

problematic to Japanese sea transport in some localities. We therefore initiated a project to investigate ap-

proaches for minimizing risk to both ships and cetaceans. Under the present project, the following three sub-

projects are underway: clarifying which whale species are found near sea routes and determining their season-

al variations; identifying whale species that have a high collision risk; and determining the unique acoustic

characteristics of high-collision-risk cetaceans for the improvement of underwater speakers (UWS). By con-

ducting acoustic surveys using novel methods, including an anatomical approach based on characteristics of

the inner ear, the aim of this project is to accurately estimate the audible range of species with a high collision

risk and improve the sounds generated by the UWS. Thus far, we have identified the cetacean species at high-

risk in two major sea routes. In the next phase of the study we plan to develop an imaging system that recog-

nizes a cetacean's unique blow using an infrared camera, in an attempt to warn of the approach of high-

collision-risk whale species at an early stage by sounding an alarm.

144

Beginning around the year 2000 in Europe, the

Agreement on the Conservation of Cetaceans in the

Black Sea Mediterranean Sea and Contiguous Atlan-

tic Area (ACCOBAMS), which is based on the Bonn

Convention on the Conservation of Migratory Spe-

cies of Wild Animals (UNEP/CMS), was formed in

response to increased concerns about collisions be-

tween large cetaceans and ships. In tandem, discus-

sions were also initiated at the International Whaling

Commission (IWC), which is the main organization

for the management of cetacean stocks and whaling

issues. In 2008, at the 60th IWC Annual Meeting

held in Santiago, Chile, cooperation with the Inter-

national Maritime Organization (IMO) was strength-

ened, as proposed by the Netherlands, and this coop-

eration was also promoted at the 61st IWC Annual

Meeting held in June 2009 in Madeira, Portugal.

Under this cooperative effort, both international or-

ganizations organized the Joint IWC-ACCOBAMS

Workshop on Reducing Risk of Collisions between

Vessels and Cetaceans (Anon, 2010).

Against this background, this paper outlines our

research project aimed at reducing risks to both

ships and cetaceans against sudden collisions, par-

ticularly for large cetaceans, and discusses future di-

rections in this field. The main sections of this paper

have been taken from selected sections presented in

a previous paper by Kato (2009).

2 WHY IS OUR RESEARCH PROJECT

NECESSARY?

The IWC, ACCOBAMS, and IMO regard collisions

between large cetaceans and super high-speed ves-

sels as one of significant threats to the survival of

cetaceans. Their main strategies for deterring such

collisions are clear and simple, and involve requiring

HF vessels to settle on the surface and reduce speed

whenever whales appear, and establishing protection

areas for whales. However, as these approaches will

not always prevent collisions, additional research

projects to identify more effective strategies are nec-

essary.

Japan, which is completely surrounded by sea,

has a population of approximately 130 million peo-

ple. The Japanese population is predominantly con-

centrated in urban areas, whereas in rural and moun-

tainous areas, extreme depopulation is occurring.

The numerous islands surrounding Japan are no ex-

ception; the depopulation of the once well-

developed islands will devastate them, leading to

environmental damage and disturbances to the coast-

line, which will eventually penetrate the offshore ar-

eas. HF vessel services help limit the depopulation

of the islands, as they drastically shorten the travel

time between them and the mainland, making fre-

quent travel more feasible. However, increases in the

number and frequency of HF vessels on sea routes

poses increased risk for collisions between vessels

and cetaceans. . The main goal of our research pro-

ject is to identify effective approaches for limiting

the risks associated with collisions between large ce-

taceans and HF vessels.

3 OUTLINE AND PROGRESS OF THE

RESEARCH PROJECT

In April 2006, the Maritime Bureau of the Ministry

of Land, Infrastructure, Transport and Tourism es-

tablished a committee for considering safety

measures for HF vessels. The Laboratory for Ceta-

cean Biology at Tokyo University of Marine Science

and Technology, based on the working group estab-

lished by the above-mentioned committee, began

conducting research on collision avoidance by seek-

ing the cooperation of Kawasaki Shipbuilding Cor-

poration, a maker of Jetfoils (JF) which are the main

type of hydrofoil-type HF vessels, KHI JPS Co.,

Ltd., which is in charge of HF vessel maintenance,

and several additional companies, such as Sado

Kisen Co., Ltd., and Tokai Kisen Co., Ltd., which

operate JF services.

A number of HF vessels are equipped with un-

derwater speakers (UWS) that emit sound waves

with the aim of repelling cetaceans. However,

whales (86 species in total; 14 species within the

suborder Mysticeti and 72 species within the subor-

der Odontoceti, as recognized by the Scientific

Committee of the IWC in 2010) differ markedly in

their acoustic characteristics depending on the spe-

cies, particularly between baleen whales, which are

highly adapted to the ocean, and toothed whales,

which have retained numerous traits from their ter-

restrial mammal ancestors (Fig. 3).

Figure. 3 Differences in the sonar frequency bands of cetacean

species grouped at the sub-order level of taxon. Cited literature

for sonar frequencies: Mysticeti (baleen whales), Au, 2000;

Odontoceti (toothed whales), Backus and Schevill, 1966.