Concept study for offshore seaweed farming

Abstract

Seaweed has been part of human consumption ever since humanity met with the oceans. As technology developed more applications for these macroscopic algae were discovered. Global population increased, technology advanced and people started to understand the lifecycle of seaweed allowing them to cultivate seaweed. Seaweed is currently cultivated in countries like China, Korea and Japan and is predominantly harvested manually. The seaweed industry has seen tremendous growth in the past two decades, increasing the call to scale up production by mechanization. Coastal sites are running sparse, and concentration of this industry has already caused major environmental problems. The solution would be to move further offshore, at a larger scale, with mechanized cultivation systems being able to cope with adverse conditions. As maritime industry market leader, Royal IHC has been at the forefront of technological advancement in a multitude of maritime operating fields. With a continuous need to develop, Royal IHC, through MTI Holland, is investigating the possibility to add value to the development of technology and equipment to service the seaweed industry. This thesis will present a market overview and research in various topics in order to evaluate the overall problem space. Based on the Integrative and Rational method, as proposed by Cross (2008), multiple design support tools are used to identify opportunities, clarify objectives and establish functions and requirements. The scope of the assignment has been closely adapted to current market needs: To develop aquacultural machinery able to service a demonstration farm (50 ha), able to demonstrate the economic feasibility of offshore cultivation. At the moment multiple pilot projects are run to demonstrate different cultivation techniques and offshore structures. A process chain has been developed to determine the mission profile, task-related functions, and compile a list of objectives. Using a function modelling method these are further decomposed into sub functions. The functions are used to generate a set of requirements for the initial concepts. Using state-of-art information on technology currently used in relevant industries, a global patent search and brainstorm sessions, a multitude of solutions were generated. These solutions are captured and organized in multiple morphological overviews. Selection criteria allowed a first filtering stage for most sub solutions and the remaining solutions provided enough information to develop four different concept designs. Using the weighted objectives method the designs where compared based on ten differently weighted objectives. The highest scoring concept was used to develop the final concept design. Using Autodesk Inventor the model was developed and partially engineered. The machine is able to harvest line based substrates with different species of seaweed attached to a set of floaters. The design can be used on a number of different carrier vessels and is containerized to be transported and deployed worldwide. The design is able to harvest farm sizes of up to 100 ha, depending on patch configuration and vessel manoeuvrability. It is scalable since it uses basic design principles and parts that can be produced in most marine production facilities. To aid in further design development and feasibility assessment of different cultivation scenarios, an exploitation model has been developed. Through optimizations on a multitude of scenarios the model proved to be an effective method to assist with design decisions, operations planning and concept feasibility. With this thesis and the exploitation model, Royal IHC is prepared to lead development of products and services in this innovative market. Future industries and researchers will benefit from this basis for development in the North European Seaweed market.