The human population is increasing and alternative methods must be developed to feed the future generations in a sustainable manner. One way to meet this demand is to introduce aquacultural farming such as seaweed farming.
Seaweed has the benefits of being fast growing, easy to control, healthy, and requires little space to farm. Since about 70% of the Earth’s surface is covered by water, the possibilities for upscaling are tremendous.
Today, seaweed harvesting is mostly done by hand. This is a fairly slow process and results in slow production rate and high prices for the end consumer. It would be advantageous to create a machine that could harvest the seaweed faster and more efficient. By attaching such a machine to a fishing vessel, it could work with existing farms and infrastructure, while increasing the amount of seaweed that can be produced.
Seaweed farms are typically made or ropes in a parallel or matrix configurations. The ropes are saturated with seeds and lowered into the ocean for several weeks or months until the seaweeds are fully grown.
The concept consists of a system that can be attached to a fishing vessel. Attached on each side or behind the vessel, the system lifts ropes out of the water so that the seaweed can be harvested.
A modular floating frame acts as the supporting structure of the system. Topology optimized and resistant to the harsh environment, the frame allows the ropes to pass underneath and handled by the harvester unit. Each section of the frame is kept level by a float, and can be attached to a subsequent frame. This means that multiple, identical units can be attached in series to increase the capacity of the system. Depending on the farm design, the number of units and the distance between them can be customized for optimal performance.
Attached to each frame, guide rollers make sure that the ropes are held above the water level as seen in Figure 3. Consisting of at least two rollers, the rope passes over in a smooth and controlled manner. To allow for deviation in yaw of the fishing vessel, each roller unit can rotate on a vertical axis. This allows for accurate positioning of the ropes relative to the floating frame and means that the seaweed can be harvested automatically.
By the use of a spinning blade in the middle of the two rollers as seen in Figure 4, the seaweed can be cut off at the stem without damaging the rope itself.
The cut off seaweed then drops down to a conveyor belt that transports the seaweed to the next harvester unit and onto the fishing vessel.
In the case of vertical seaweed farms, an additional unit can be attached to the main harvester unit to increase its functionality. Indicated by a red marker, the intersection between a vertical rope and the horizontal parent rope is sensed. This allows the machine to automatically catch the vertical rope and start harvesting.