Objectives  The influence of submarine's internal tank on the acoustic target strength control is studied.

  Methods  The planar element method based on Kirchhoff high frequency approximation was used to calculate and analyze the influence of internal tanks at different positions inside the submarine's pressure hull on the target strength, and their control effects of four tank structure improvement schemes were calculated and analyzed.

  Results  The results show that the internal tank mainly affects the target strength in the frequency band from 1 kHz to 3 kHz. The internal tank located near the centerline of the broadside has little effect on the original target strength, while the tank at the bottom of the broadside has a great impact on the original target strength. The calculated results show that the inclination of the interior wall of the tank located near the centerline can help reduce the target strength in the normal incidence direction. However, the inclination of the interior wall of the tank located at the bottom can significantly reduce the target strength in the frequency band above 3 kHz, but the reduction effect on that in the low frequency band between 1 kHz and 3 kHz is not enough to make up for the influence caused by the internal tank.

  Conclusions  In the design of submarine, corresponding measures should be taken to reduce the influence of the internal tank on the target strength.