A large drill ship or semi sub often has two fingerboards with around 500 latches per board. The weak spot in this system is the fact that the latches are operated without any status information. The fingerboards on most drilling rigs actually lack active feedback on the position of the latches. These latches are pneumatically forced to open and close, without knowing whether or not this opening or closing actually takes place. Because of the rough conditions on board, with the presence of mud, salt, and water, failing latches can result not only in damages to the equipment but also in severe injuries. If a latch remains closed when it should have been open, latches may break or even worse, (part of) the fingerboard may come down.
A dedicated spotter must therefore visually check the operations to promptly notice failing latches. The presence of the spotter on the (dangerous) drill floor is highly undesirable, and the reason is twofold. First of all, because of safety reasons, the fewer people on the drill floor the better, and secondly due to the high costs involved. Last but not least, people are not really effective in 12 hours observation jobs.
Various technical solutions are available to replace the use of a dedicated spotter. These solutions generally involve active response systems or static sensors. Both approaches are complex and expensive and in the case of sensors, extremely vulnerable. Over a 1,000 sensors are required on a drillship, which results in around 1,000 additional points of failure.