Modern marine seismic cables are equal-buoyancy combined cables with uniform cross-sections. They are composed of 24 or 48 combined sections, each combined section is about 50-100 meters long, and many geophones are connected in parallel or in series. The combined sections are connected by sealed and waterproof stainless steel joints for easy replacement or maintenance. The entire cable has a few hundred meters of geophone-free section at the stern, and sometimes a shock absorber is attached to eliminate the influence of propeller vibration. At the end of the cable, there is a 50-100-meter long section without detectors and a director to reduce the cable swing. In order to make the cable have equal buoyancy performance, it is usually filled with oil, air or foam plastic in the plastic tube containing the cable and the geophone. In order to maintain a stable depth during work, attach appropriate loads to the front and tail sections of the cable without detectors, and use a depth fixer to keep the entire cable at a depth of 5-7 meters underwater.