The in-situ restoration and conservation of submerged archaeological assets aim to ensure their preservation and transmission to future generations. The deterioration of these artifacts is primarily caused by biofouling and water quality. Depending on the extent of degradation, an initial cleaning phase is typically followed by a consolidation phase. To date, no dedicated tools have been developed for this consolidation process, and manual or pneumatic tools are commonly used, often leading to various inefficiencies. To address this issue, the paper proposes a novel injector device specifically designed to enhance the efficiency and effectiveness of the work carried out by underwater restorers and archaeologists for the consolidation and conservation of the submerged archaeological remains. The proposed device is a cordless mechatronic instrument that enables the precise application of consolidating mortars in underwater environments. Additionally, it features an innovative mortar storage system with an automatic rotating cartridge, which significantly improves the efficiency of the consolidation process. The paper presents the modular architecture, technical solutions, and key features of the proposed injection underwater device.