ship speed related to torpedo damages

is there a way to tweak ship speeds to slow x amount for 1 torpedo impact that causes damage but does not sink ship? some ships do slow down but often it is only because they are sinking from that hit.

i hate hitting a vessel with torpedo and there is no, i repeat no reduction in speed.

i dont expect it to stop but maintaining full speed is laughable.

is this a tweakable issue or hard coded?