Steel Big

Steel Big is a 70m long, 700-ton wreck in the Gulf of Thailand, lying at a depth of 65m, with the starboard deck rising to 55m. It serves as a warmup dive for deeper expeditions. Despite its unknown history and lack of notoriety, it offers extensive penetration opportunities and remains an unsolved mystery. Diving requires self-organization and the use of a shot line for descent and ascent, as there is no mooring line.

Due to its remote location, divers must prepare for contingencies and bring ample oxygen, as medical help is 12 hours away. The wreck is generally intact, with minimal issues from nets or currents. Key areas of interest include the bridge, forecastle, bow, and engine room, all accessible with no signs of major salvage attempts.

The dive is recommended for experienced divers, typically requiring CCR trimix due to depth and remoteness. Open circuit diving is possible but challenging. Divers often use bare boats and bring their own supplies, with Seascout Diving in Bangkok recommended for trimix blending and oxygen boosting. Deco tanks should be carried throughout the dive, with additional gas staged on the shot line. The wreck was discovered by local fishermen, with diving beginning around 2015. Related wrecks include IJN Tottori Maru, IJN Big Boy Maru, HTMS Phangan, and IJN Burma Maru.