A subsea processor may be located near the seabed of a drilling site and used to coordinate operations of underwater drilling components. The subsea processor may be enclosed in a single interchangeable unit that fits a receptor on an underwater drilling component, such as a blow-out preventer (BOP). The subsea processor may issue commands to control the BOP and receive measurements from sensors located throughout the BOP. The subsea processor may relay information to the surface for recording or monitoring. The subsea processor may also be programmed with a model from which to base operation of the BOP, such as in emergency conditions.