By the way, I have a feeling that on my system the game is not using all cores / threads.
The teammate has a laptop, he has the same set of 55-60 FPS ships at sea. I have a PC and I feel a strong FPS drawdown, and the task manager shows that the CPU is loaded by 10%.
CPU type 12-Core AMD Ryzen Threadripper 2920X, 4300 MHz (43 x 100)
ASRock X399 Taichi Motherboard (1 PCI-E x1, 4 PCI-E x16, 3 M.2, 1 U.2, 8 DDR4 DIMM, Audio, Dual Gigabit LAN, WiFi)
System memory 130953 MB
Video adapter GeForce GTX 1080 (8 GB)