Trammel net design engineering for operation with the sweeping method (Ciker net)

Zainal Wassahua,Sulaeman Martasuganda,Muhammad Fedi Alfiadi Sondita,Mulyono Sumitro Baskoro

doi:10.13170/depik.10.1.18219

Abstract

The active operation of a trammel net by a sweeping technique is commonly used by fishermen in Cilacap, which are often referred as ciker nets. They are operated by lowering the net in a straight line and pulling the tail end from a ship moving in a full circle, while the other end functions as a circular axis. The effect of active operation allows for changes in performance with time, such as easy lifting or less buoyancy, and the unstable display of gears. This makes it necessary to perform design engineering, especially on buoys, sinkers, and high nets. However, the suitable quantity of these components for ciker net has never been ascertained. Calculations about how many buoys, sinkers, and net height to add need to be done to enhance ciker net construction for active operation. This research aimed to determine the optimum configuration of buoys, sinkers, and net height, and determine the engineering design of ciker nets based on the optimum ratio of buoyancy force to the sinking force of the trammel net. Therefore, the parameters measured include hanging ratio, stretched net length, buoyancy force, and sinking force. The results showed that the optimum configuration of buoys, sinkers, and net height was 59 pieces, 341 pieces, and 1.5 m respectively. Changes in the design of ciker nets, especially in the three components that affect the addition of buoyancy and sinking force ratio were based on the comparison of the trammel nets which was 1:5 greater than the design owned by fishermen at 1:4.Keywords:Bouyancy forceSinking forceCiker netTrammel netShrimp

Highlights

A Trammel net is used to catch fishes by capturing in a net (Aulia et al, 2020)
The active operation of a trammel net by a sweeping technique is commonly used by fishermen in Cilacap, which are often referred as ciker nets
This research aimed to determine the optimum configuration of buoys, sinkers, and net height, and determine the engineering design of ciker nets based on the optimum ratio of buoyancy force to the sinking force of the trammel net

Summary

Introduction

A Trammel net is used to catch fishes by capturing in a net (Aulia et al, 2020). The construction consists of three sheets of nets, namely two sheets in the outer net having larger mesh size, and 1 sheet of inner net having small mesh size. (Subani dan Barus, 1989). Mangunsukarto et al (1993) stated that low shrimp production from the trammel net is highly related to the method of use or operation, as a set bottom trammel net. The second is by active operation, which involves lowering the net in a straight direction pulling the tail end of the net with a vessel moving in a trajectory that forms a full circle or semicircle, while the other end serves as a circular shaft (Matuda and Kitahara 1967; Nomura and Yamazaki 1977) This second way is called the sweeping trammel net technique, and is a type of entanglement fishing gear operated by a circular or semi-circular sweeping of the sea bed (Kitahara, 1968; Kitahara and Matuda, 1967; Matuda and Kitahara, 1967; Purbayanto, 2001; Purbayanto et al, 2008, 2000; Tupamahu and Latumeten, 2006). The sweeping trammel net method has been used by fishermen in various places, including on the southern coast of Java Island, and the coast Cilacap, where they are known as ciker nets

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