The results obtained show that the addition of aluminum (Al) and aluminum hydride (AlH3) to the explosive significantly increases the heat of explosion and the TNT equivalent (TE) of an underwater explosion. The compositions with AlH3 are inferior to the Al-containing counterparts in the heat of explosion. However, the formulations with AlH3 have the advantage in terms of the number of moles of gaseous products. Replacing Al with AlH3 weakly affects the TE in terms of the energy of gas bubble, while the TE in terms of the energy of shock wave is higher for the mixtures with AlH3. The latter is especially noticeable in the case of the explosive with a positive oxygen balance. However, the compositions with AlH3 are inferior to the Al-containing mixtures in the volumetric TE.