In my opinion, though chances are, that I am probably very wrong, At a scale speed, a ship like Nord Icelandia, at her scale, she should just be developing a bow wave, rather than having her anchors swept under. maximum speed for a vessel like her would be around 10 to 15 knots, which would be somewhere around 20km/h, and she wouldn't put a 6 foot wave on her bow.
I have tried to set her EPA up so that at full speed she is at scale full speed