To protect ship equipment of river and sea transport, it is suggested to use polymeric protective coatings based on epoxy diane oligomer ED-20, polyethylene polyamine (PEPA) curing agent and filler, which is a departure from industrial production. Thus the purpose of the work is analysis of major dependency of the properties on the content of fillers that allowed to revealed the critical filler content (furnace black) in composites to form a protective coating with the required set of characteristics. The infrared (IR) spectral analysis was used to investigate the presence of bonds on the surface of particles of the PM-75 furnace black, which allows us to assess the degree of cross-linking of the polymer. The influence of the content of dispersed furnace black on the physicomechanical and thermophysical properties and the structure of the protective coating is investigated. For the formation of the coating with increased adhesive properties, the optimum content of the additive is q = 25 parts by weight (pts.wt.), due to the increase in the number of C—O, C—C, C═O, C═C, C═O, and O═C—H bonds. For the formation of the coating with increased cohesive properties, the optimum content of the additive is q = 20 pts.wt., which is associated with the maximum compaction of the polymer spatial net. On the basis of the analysis of the surface of the composite fracture, a homogeneous topology of the fracture surface was found which characterizes the viscous state of material destruction at the content of the additive q = 5 pts.wt., which provides significant improvement of the physical and mechanical properties of the materials developed. Additionally, it was found that when the PM-75 particles were introduced at the content of q = 10-30 pts.wt., the uniformity of the structure is retained, but its abnormal similarity is observed. This allowed us to determine the optimal content of the additive (q = 20 pts.wt.) for the formation of coatings with high cohesive strength in the complex.