This paper presents the design and implementation of a solution to control theft of outboard motors of small fishing boats. The lack of control of outboard motors inventory, in-situ identification and especially thefts have come up with a possible solution of the problems mentioned before by using passive RFID tags. The RFID equipment that is part of the solution should adjust to adverse conditions where they will work: salinity, high temperatures, vibrations and external interferences particularly those that come from the outboard motor. The essentials in this paper are the specific tests that will provide the knowledge of the real coverage and reception of data using RSSI (Received Signal Strength Indication) and the use of propagation models in the forward and reverse link.