Final answer:
The self-locking twin-doughnut hose roll appears to be part of an engineering setup, likely for marine purposes. It involves PVC pipes with rubber rings for slow release of substances and is carried in mesh bags, emphasizing the significance of sturdy and watertight materials.
Step-by-step explanation:
The self-locking twin-doughnut hose roll, which seems to be related to a method of deploying equipment for marine research or similar engineering operations, is typically carried and refilled using a specific set of materials and tools. The refills for the described system consist of PVC pipes with holes and rubber rings. These pipes are designed to slowly release a compound, such as CS (which could possibly stand for a chemical substance), when placed under a tarp in the marine environment. The structure of the covers is crucial as they are made from durable plastic materials and geotextiles, featuring stainless steel washers to maintain their position and integrity.
To ensure that the hose rolls are watertight and to facilitate the deployment process, the design incorporates nylon lids on one end and screw-on PVC lids on the other. For carrying the rolls, they might be securely packed in mesh bags for ease of transportation and quick deployment. Given the context and the materials mentioned, this sort of equipment is aligned with practices in the field of engineering, specifically that which relates to marine, environmental, or civil engineering.