A mounting block for fastening equipment such as a sonar transducer onto the hull or transom of a boat which consists of a flat body portion formed into a predetermined size and shape, the body further having a front face and a back face, the back face further having one or more channel grooves for retaining an adhesive, the channel grooves further having internal surfaces to provide mechanical grip to the hardened adhesive thereby preventing mechanical separation between sonar transducer or other equipment and the mounting block.