- Safe and Reliable Deployment & Recovery of Payloads
ODIM Brooke Ocean has produced a number of load latches for use with our launch and recovery systems (LARS). The load latch is used to secure the payload once it is hoisted clear of the deck (on launch) or the water (on recovery). Removing the load from the lifting cable is a benefit with systems where the winch is mounted separately from the lifting device, as it eliminates the need to simultaneously operate the winch and lift device controls. Two types of load latches are used: actively-latched and passively-latched.
How our load latches work:
Passively latched systems automatically latch to latch points on the payload. The latch point is located either on the payload or incorporated into a special cable termination. These latches fall into two categories:
| a) | the payload is hoisted into the load latch - the payload is automatically latched (by spring-loaded latch plates that engage the latch point) when the load is hoisted to a maximum hoist point. A limit switch interfaced to the hoisting winch prohibits hoisting beyond this point. The operator lowers the payload until the latches take the weight, allowing the lift cable to go slack. Unlatching involves the operator hoisting up until the latch point is clear of the latch plates. A limit switch (interlocked to the winch) prevents hoisting past this point. The load latch is then opened using small hydraulic cylinders and the load is lowered. As an added failsafe, the hydraulic cylinders are not powerful enough to accidentally unlatch while the load is applied. |
| b) | the latch is lowered onto the payload - The latch assembly, suspended from a mechanical cable, is lowered to the payload along an umbilical cable. This method is used with tethered ROVs and other payloads where the umbilical cable cannot be used to lift the ROV. Once the payload is near or at the surface, the latch mechanism is lowered until it automatically latches to the payload. When the payload is hoisted up and onto the deck, hydraulic cylinders release the latch plates from the payload. The cylinders are sized so that they cannot unlatch the payload unless the load is removed. Indicator lights inform the operator when the latch is engaged with the payload. |
The passively latched systems are used with ROV, hardsuit and CTD handling systems.
Actively latched systems are used with ODIM Brooke Ocean's vehicle launch and recovery systems. Once the vehicle is hoisted into the capture mechanism, the operator activates the hydraulically-actuated latch plates to move into position under a custom cable termination fitting. The load is lowered until the termination rests on the latch plates. Proximity switches indicate the position of the locking plates, and limit switches ensure that actuation of the plates occurs only when the load is on the lifting cable. As an additional failsafe, the hydraulic cylinders that actuate the locking plates do not provide enough force to open the plates while under load.
Submarine Pod Posting System
A passively latched, hydraulically released latch system integrated into an overboarding sheave with metering capabilities. The system latches onto a latch point incorporated into the wire rope termination. This system is part of the ELSS emergency POD posting system.
Crane-Based Launch System
This LARS uses a passively latched, hydraulically released latching system to secure a Hardsuit diving suit for recovery. The Hardsuit has a neutrally buoyant tether passing through the latch assembly. The assembly is split and hinged to allow installation around the tether.
A similar system is used for securing a lifting cable onto an ROV. The latch assembly, attached to the main lifting line, slides down the ROV tether and latches onto a bullet-shaped structure on the ROV.
CTD Rosette Handling System
This CTD handling system uses a passively-latched, hydraulically-released latching system to secure a CTD rosette. The latch is integrated into an overboarding sheave, and latches onto a titanium disk bolted 
to the CTD rosette. Limit switches on the latch arms are interfaced to the hoisting winch and latch release switch, prevent over-hoisting and unintended unlatching.
The Dolphin, ORCA, Thales and DSTO launch and recovery systems all use versions of the actively-latched, actively-released latch systems, which are incorporated onto the LARS capture mechanisms. Special wire rope terminations interface with the latching systems to allow safe transfer of the vehicles to and from the vessel.
Contact ODIM Brooke Ocean to discuss other applications for load latches.Home · Contact Us · Top · www.odim.com
Contents Copyright ©2008 ODIM Brooke Ocean
URL: http://www.brooke-ocean.com/load_latch.html (Last Updated: Mar 03, 2008)