First decide the net’s purpose—tide capture or fish fishing? That dictates size and shape. Pick a high‑strength, UV‑stable mesh like 0.5‑mm nylon or a carbon‑fiber composite; keep it flat enough to avoid snagging but stiff enough to stay in shape. Next, add a set of tensioned anchor points along the top edge—simple winches or weighted buoys that adjust automatically when the wave pulls. The key is passive feedback: as the wave rises, the anchor tension increases, stretching the net into a concave shape that follows the crest. Use a curved support frame, perhaps a shallow aluminum arch, so the net stays in contact with the water without piling up. For stability, attach a few weighted loops at the bottom that shift with the water flow, keeping the net from spinning. Finally, test in a small tank with a wave generator; tweak the anchor spacing until the net moves smoothly with each swell. Keep the design modular, so you can swap materials or add a simple elastic band if you need extra flexibility. No fancy electronics needed, just solid mechanics and good materials.