International Journal of Innovative Research and Development

Sunny Verma , Kareem Khan , P. C. Praveen , Manu Korulla , P. K. Panigrahi

Abstract

Trimaran is the most promising hull form for naval vessels because of its excellent performance characteristics notably reduced wave making resistance, larger deck area, good sea keeping and ability to perform optimally in a range of speeds. In its most generic form it consists of a slender centre hull and two side hulls. High slenderness ratio, differential breadth to draft ratios, stagger/separation of the hull forms gives an edge over equivalent monohulls/catamarans in minimising wave making resistance. However it's furher possible to reduce the wave making resistance by means of advancements to the existing design which can include bulb & wave piercing forms, stern wedge/flap/interceptors, asymmetry in side hull configuration, lifting bodies etc. The present paper investigates the qualitative performance of trimaran hull form modified to various configurations using Shipflow.

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Shiju John , Kareem Khan , P. C. Praveen , Manu Korulla , P. K. Panigrahi

Abstract

Hydrodynamic model studies were carried out at Naval Science & Technological Laboratory (NSTL), Vishakhapatnam, India to estimate the resistance contribution of appendages. This paper discusses categorization of ship hull appendages from a hydrodynamic viewpoint. An attempt is made to qualitatively assess the resistance contribution of each of these categories of appendages to the total ship resistance. A relative appraisal of the resistance contribution of appendages on a naval surface combatant, a submarine, a tanker, a container, a dredger and a single screw ship is made to emphasize the large appendage drag on naval ships. Results obtained from hydrodynamic model experiments conducted at High Speed Towing Tank (HSTT) facility at NSTL on a fast displacement hull form used for naval applications (FDHFNA) are discussed at length as a case study. A criterion for rating appendages is proposed.

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