Set of marine warning and exploration line icons

A clean black-and-white icon set is arranged in a four-panel grid on a white background. The drawings include a small submarine, an anglerfish, a steaming volcano, and a circular gauge with wave markings and an arrow. Each symbol uses simple outline strokes with plenty of negative space, giving the image a crisp technical feel. The flat composition and monochrome palette make it suitable for educational graphics, marine navigation themes, and general infographic use. No shading or realistic detail appears; the design stays minimal and easy to read at small sizes. The icons suggest underwater exploration, hazards, and environmental monitoring without tying the image to a specific location or brand.