Danbuoy - FOLDING auto spring out
NZ made - easy release.
Conventionally these are stored on your boat attached to a backstay (or sidestay) so the buoy on the unit, being specially designed for this purpose, and the folding action gives you minimum diameter.
The clever hinging mechanism is pre loaded with an integral shock cord making the unit automatically launch to full length upon release from the half folded storage.
Normally we attach to a side stay or pushpit with a simple 2"(50mm) x 8" (200mm) plastic tube, both at the bottom and at the top, hose clamped to the stay. The danbuoy then simply slides into it and to release lift the buoy vertically (which frees it from the bottom tube and slide it down into the water - the auto hinging mechanism releasing as soon as it is freed from the top tube.
The big plus here is the natural deployment not needing a gas canister of needing recharging - it can be used virtually unlimited times without repair or parts such as found with the gas canister types.