Inspired by humpback whale belly grooves which may impart stability, we hypothesized that adding grooves to the head of submarine-launched vehicle (SLV) would weaken the effect of wave force. An experimental instrument was built to test a prototype submarine-launched vehicle (SLVP; no grooves) and 9 bionic submarine-launched vehicles (SLVBs) with different grooves on the head. The deflection angles of the SLVP and SLVBs were measured as they crossed the water-air interface in wavy conditions. The experimental results showed that the SLVBs had smaller deflection angles than the SLVP, which supported the initial hypothesis. The angular deflection of the SLVP and SLVBs in wavy conditions was then analyzed using a simulation. The simulated and experimental results agreed, confirming the validity of the simulated models. By measuring the torque experienced at the center of gravity of the SLVs and the flow field distributions near the heads of the SLVs in the simulation, the mechanism behind the differences in angular deflection of the SLVs with and without grooves was revealed. • Inspired by humpback whale, we hypothesized that adding grooves to the head of SLV would weaken the impact of waves. • An experimental instrument was built to test a SLVP (no grooves) and 9 SLVBs with different grooves on the head. • The experimental and simulated data supported the correctness of the hypothesis proposed in this paper. • The reason behind the differences in angular deflection of the SLVs with and without grooves was revealed. [ABSTRACT FROM AUTHOR]