01Tetra pod incident overview
According to data collected by the Korea Coast Guard from 2017 to 2025, a total of 331 safety incidents related to tetra pods (sofa blocks) were reported.
Among them, fatalities numbered between 40 and 46, resulting in an incident fatality rate of approximately 12%. This is markedly higher than coastal fishing accidents overall.
Cumulative counts by region are: Gangwon 107 incidents (11 deaths), Gyeongbuk 67 (5), Busan 39 (4), Jeju 35 (7), Ulsan 27 (3), and a similar trend has persisted over the past five years (2020‑2024).
02Structural hazards of tetra pods
Tetra pods have a rounded surface that readily accumulates algae, maximizing slipperiness. Strong currents can create deep gaps between blocks, causing feet to become trapped or slip, increasing the risk of falling.
In particular, the gaps between blocks measure about 30–70 cm, making it difficult for an adult over 80 kg to free themselves unaided. Attempting to escape underwater then rapidly depletes stamina due to water resistance and pressure.
Additionally, the area around a tetra pod experiences a ‘dolphin effect’ where waves cause sudden water level rises and drops, making it hard to maintain balance when the feet become submerged.
03Causes of incidents and prevention principles
The primary causes are: ① slippery surface, ② deep gaps between blocks, ③ delayed rescue requests during solo outings. When these three combine, an unrecoverable situation can arise.
Prevention requires wearing a life jacket and shoes with non‑slip soles (rubber or rubber pads). Additionally, at least two people should work together, continuously monitoring each other's positions.
During pre‑trip site inspections, avoid areas around tetra pods with heavy algae growth or rapidly moving water, and choose flat rocks or sandbars whenever possible.
- Not wearing a life jacket– Statistics show wearing one doubles the survival rate
- Solo outing – rescue request delayed, exceeding recovery time
- Standing directly on algae‑covered blocks – sharply raises slip risk
04Practical Application Checklist
We organized a pre‑trip checklist into five steps. The first is ‘equipment inspection’, the second ‘site pre‑survey’, the third ‘role assignment with teammates’, the fourth ‘emergency signal verification’, and the final ‘post‑trip report’.
- Confirm life jacket and non‑slip shoe wear
- Photograph algae and gap conditions around the tetra pod
- Maintain a 10 m distance with teammates; check whistle and radio
- In emergencies, verify contact numbers for 119 and the Korea Coast Guard
- Record incidents and hazards after the outing ends
05 FAQ
- Q: If I only catch fish around a tetra pod, can I ignore the danger? A: Even if fish are caught, the surface remains slippery and the gaps deep, so the fall risk does not change. Approaching without safety gear keeps the fatality risk at about 12%.
- Q: Is it safe if there’s only a floating buoy without a life jacket? A: A buoy is useful only for marking location. Its buoyancy is far less than that of a life jacket, so rescue time lengthens and the fatality rate rises sharply.
- Q: What precautions should I take when fishing alone? A: If you are alone, you must inform another angler of your outing plan, share real‑time location via GPS and radio, and send a check‑in signal every 30 minutes.