Underwater search and salvage in Lianjiang, Fuzhou

May 08, 2020 by Ivan Xie

Time: April 15, 2020

Location: Tailu town, Lianjiang County, Fuzhou City, Fujian Province (East China Sea)

Model: CHASING M2 (In charge of equipment search, undersea environment confirmation)

Purpose: Salvage Seabed Machine


According to the customer, a sea-bed engine is out of contact because of the malfunction of Communication Sonar equipment, which leads to the lost of the sea-bed engine. The manual diving search efficiency is low, the risk is high, and the underwater search and rescue equipment is urgently needed to improve the search and rescue efficiency.

Harbour & ocean conditions

Distance: 1.5~2 km

Tide: Ebb

Sea wind: Level 1~2

Velocity of flow: 25 cm/s

Turbidity: >300NT U

Bottoming visibility: 0.5 m

Depth: 23~25 m


Salvage Process

Step 1: To determine the shape and size characteristics of salvage objects and what might be around the target (cables and fishermen abandoned cages).

Step 2: Determine the search area

Before it was lost, the approximate search area (about 40 meters radius water area) was determined by previous location records.

Step 3: Search with M2

The current velocity is more than 25cm / s, and the counter current search has some resistance and the overall search condition is stable. The sediment layer is thick (the prediction is in the range of 0.3 m ~ 0.5 m). The distribution of multi-silted mud mounds can roughly determine that about 1 / 3 part of the target object has been sunk into the mud, and make the plan of fishing tools.

After finding the target fixed cable and locking target location (lock range: 25 ㎡), wait for the human salvage.

Step 4: Diver follows the M2 wire of buoyancy and follows it down to the target.

According to the M2 pre-search feedback, the diver prepared a series of positioning and fishing tools to dive, about 15 minutes to complete the

target object fixed point and lifting rope installation.

Step 5: Lift and salvage the target.


What is CHASING M2's role in this event

1. Improve the efficiency of salvage and  job security in complex underwater environments.

2. The clear pictures and videos help to accurately determine the underwater situation.

3. Accurate depth and temperature data helps to quickly formulate salvage plans.

4. The battery can be removed and replaced, and the working time is not limited.

5. Save costs and reduce the risk of working underwater.