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Dihedral bows: a new type of bulbous bow for small vessels

Dihedral bows: a new type of bulbous bow for small vessels
Dihedral bows: a new type of bulbous bow for small vessels
This paper presents the experimental results of a new type of developable added bulbous bows that have been named as dihedral bows. These type of bows are based on polyhedral bows that are used in small vessels whose origin is traced to 1990’s. The bow is designed with two developable surfaces that are designed following previous methodology on surfaces that consider material properties and will contain some chine lines. Two dihedral bow designs and their towing tank tests are presented in this work in still water, comparing the effect of the dihedral bow vs. original designs. The tests covered displacement, semi-displacement and planning hulls, tested in two different loading conditions each and for different Froude numbers. The lines of the models are real ships. An important reduction of the effective power (PE) of the ships with the dihedral bow was obtained from the experiments (About a 20%), and this successful cutback into the power is the main reason of this paper. Dihedral bows are a good option for efficient small ship design like the fishing vessels presented in this paper, and is open for larger ships.
Ship Design, Bulbous Bow, Developable Surfaces
Diaz-Ojeda, Hector
6990e39d-cb55-4dbe-b943-2d728e74a0a7
Zhang, Yifu
201620b2-8af6-4747-8f3a-923c92fea4f1
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Perez Arribas, Francisco
0452937c-2dd5-42e9-a376-64189f638222
Perez Arribas, Francisco
0452937c-2dd5-42e9-a376-64189f638222
Diaz-Ojeda, Hector
6990e39d-cb55-4dbe-b943-2d728e74a0a7
Zhang, Yifu
201620b2-8af6-4747-8f3a-923c92fea4f1
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce

Diaz-Ojeda, Hector, Zhang, Yifu and Turnock, Stephen (2025) Dihedral bows: a new type of bulbous bow for small vessels. Perez Arribas, Francisco (ed.) IWSH 2025: The 13th International Workshop on Ship and Marine Hydrodynamics, , Fukuoka, Japan. 25 - 28 Aug 2025. 11 pp .

Record type: Conference or Workshop Item (Paper)

Abstract

This paper presents the experimental results of a new type of developable added bulbous bows that have been named as dihedral bows. These type of bows are based on polyhedral bows that are used in small vessels whose origin is traced to 1990’s. The bow is designed with two developable surfaces that are designed following previous methodology on surfaces that consider material properties and will contain some chine lines. Two dihedral bow designs and their towing tank tests are presented in this work in still water, comparing the effect of the dihedral bow vs. original designs. The tests covered displacement, semi-displacement and planning hulls, tested in two different loading conditions each and for different Froude numbers. The lines of the models are real ships. An important reduction of the effective power (PE) of the ships with the dihedral bow was obtained from the experiments (About a 20%), and this successful cutback into the power is the main reason of this paper. Dihedral bows are a good option for efficient small ship design like the fishing vessels presented in this paper, and is open for larger ships.

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More information

Published date: 25 August 2025
Venue - Dates: IWSH 2025: The 13th International Workshop on Ship and Marine Hydrodynamics, , Fukuoka, Japan, 2025-08-25 - 2025-08-28
Keywords: Ship Design, Bulbous Bow, Developable Surfaces

Identifiers

Local EPrints ID: 506954
URI: http://eprints.soton.ac.uk/id/eprint/506954
PURE UUID: d924cf85-98f7-4b6a-86d6-a0f9e2525c1f
ORCID for Yifu Zhang: ORCID iD orcid.org/0000-0001-6980-3985
ORCID for Stephen Turnock: ORCID iD orcid.org/0000-0001-6288-0400

Catalogue record

Date deposited: 24 Nov 2025 17:32
Last modified: 25 Nov 2025 03:12

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Contributors

Editor: Francisco Perez Arribas
Author: Hector Diaz-Ojeda
Author: Yifu Zhang ORCID iD
Author: Stephen Turnock ORCID iD

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