A buoy system according to one embodiment of the present invention includes a buoy body configured to provide buoyance; a fixing belt configured to fasten the buoy body to a ship structure; an auto-release unit configured to release the buoy body to be buoyed by releasing the fixing belt when a predetermined water pressure is reached; and an auto-reel chain box fixed to the ship structure, being opened in conjunction with releasing of the fixing belt, and including a chain which is reeled out when the buoy body is buoyed, wherein the auto-reel chain box comprises: a weight provided in the auto-reel chain box and being movable upward and downward according to a water pressure and buoyance; a pulley provided in the auto-reel chain box, having the chain wounded thereon and a plurality of teeth on an outer circumferential surface thereof; and a shaft having one end connected to the weight and the other end engaging with the teeth to fix the pulley and provided to be rotatable around a portion fixed in the auto-reel chain box.

A buoy system according to one embodiment of the present invention includes a buoy body configured to provide buoyance; a fixing belt configured to fasten the buoy body to a ship structure; an auto-release unit configured to release the buoy body to be buoyed by releasing the fixing belt when a predetermined water pressure is reached; and an auto-reel chain box fixed to the ship structure, being opened in conjunction with releasing of the fixing belt, and including a chain which is reeled out when the buoy body is buoyed, wherein the auto-reel chain box comprises: a weight provided in the auto-reel chain box and being movable upward and downward according to a water pressure and buoyance; a pulley provided in the auto-reel chain box, having the chain wounded thereon and a plurality of teeth on an outer circumferential surface thereof; and a shaft having one end connected to the weight and the other end engaging with the teeth to fix the pulley and provided to be rotatable around a portion fixed in the auto-reel chain box.

A system for securing a submerged buoy including a signalling element floating on the surface and connected to the buoy by a link, said securing system being wherein it includes a reversible coupling device comprising an attachment member secured to the end of the link opposite the signalling element, a complementary attachment member rigidly connected to the buoy and capable of engaging with said attachment member in order to allow the link to be secured to or released from the buoy, a pressure sensor, a control unit associated with a time measurement unit, said control unit ordering said complementary attachment member to separate from said attachment member when a pressure variation, measured by associating said pressure sensor and said time-measurement unit, is higher than a set value.

A system for securing a submerged buoy including a signalling element floating on the surface and connected to the buoy by a link, said securing system being wherein it includes a reversible coupling device comprising an attachment member secured to the end of the link opposite the signalling element, a complementary attachment member rigidly connected to the buoy and capable of engaging with said attachment member in order to allow the link to be secured to or released from the buoy, a pressure sensor, a control unit associated with a time measurement unit, said control unit ordering said complementary attachment member to separate from said attachment member when a pressure variation, measured by associating said pressure sensor and said time-measurement unit, is higher than a set value.

A fish recompression tool comprises an elongate body having and internal airtight chamber, an attachment member, a locking member, a piston, and a spring within the airtight chamber that engages the piston. The attachment member may switch between open and closed configurations, such that a fish is attached to the device in the closed configuration. The attachment member configuration is controlled by the locking member, such that a locked configuration corresponds to a closed configuration. The attachment member switches to the open configuration when the piston moves in response to reaching a water depth that results in the external pressure surrounding the airtight chamber being sufficiently greater than the internal pressure within the airtight chamber and the spring force on the piston. In preferred embodiments, a plug attaches to an open ended elongate body and may be moved to set different unlocking requirements (i.e. different release depths).