There is a Chinese patent on how to cut the underseas cable with low cost.
"本发明公开了一种拖曳式海底电缆切割装置及其电缆切割方法。现有需要一种快速、低成本的海底电缆切割装置。本发明的拖环固定在主杆一端,主杆另一端固定有两块翼板;两块翼板的一个侧面位于对称中心线处固定有一个锚钩,另一侧面位于对称中心线处也固定有一个锚钩;两个锚钩内侧均固定有切割刀,且每把切割刀与两块翼板之间均设有一块导铁,导铁与两块翼板均固定;铁链一端与固定在拖船上的拉力传感器固定,另一端与切割锚的铁链固定。本发明的拖船通过铁链拖动切割锚切割电缆,实现了切割锚直接在海底钩住电缆并快速切断电缆,且从拉力传感器和回收切割锚后检查切割刀上是否有残留铜屑两方面确认电缆切割是否完成,可靠性强。"
Translated this with ChatGPT
This invention discloses a towed submarine cable cutting device and its cutting method. Currently, there is a need for a fast and cost-effective submarine cable cutting device. In this invention, a towing ring is fixed at one end of the main rod, while two wing plates are fixed at the other end. On one side of the two wing plates, a grappling hook is mounted at the centerline of symmetry, and another grappling hook is mounted on the opposite side at the same centerline. Cutting blades are fixed inside both grappling hooks, and a guide iron is installed between each cutting blade and the two wing plates, which are also fixed to the guide iron.
One end of the iron chain is connected to a tension sensor mounted on the tugboat, while the other end is attached to the chain of the cutting anchor. The tugboat tows the cutting anchor using the iron chain to cut the cable. This enables the cutting anchor to directly hook and quickly sever the cable on the seabed. The completion of the cable cutting is confirmed by checking the tension sensor and inspecting the cutting blades for residual copper debris after recovering the cutting anchor, ensuring high reliability.
https://patents.google.com/patent/CN111203499A/zh