Objectives  This paper proposes a design for a floating foundation of a high strength steel cabin which simultaneously meets the requirements of impedance adaptation in acoustics and stiffness matching in mechanics.

  Methods  Typical floating foundations which are not connected with the pressure hull are studied by adjusting the structural parameters of the foundation, analyzing the impedance characteristics and intrinsic modes with the finite element method, and calculating the strength of the pressure structure along with the original and improved foundations. A scheme of a floating foundation which satisfies the design requirements is obtained.

  Results   The results show that the amplitude of the improved foundation is increased, the coupling of the intrinsic modes of the foundation with the mechanical equipment is reduced, the strength of the pressure satisfies the specification requirements, and the added weight is within the acceptable range.

  Conclusions  This floating foundation scheme can provide references for the design of large foundations for high strength steel cabins which take into account both acoustic and mechanical requirements.