You're batting a thousand. You accuse everyone (me) of not knowing what I'm talking about, but you can't manage some very simple maths.
A Nautical Mile is 2,000 yards (6,000 Ft) even, and a Mile is 1,760 Yds (5,280 Ft). Ego, a Kt is about .15 faster than a Mph because it's an additional 240 yards per hour speed over ground. It's based on the circumference of the Earth through the poles (it's larger at the equator). 360 degX60 min=21,600 Minutes= 21,600 Nm, or a direct representation of Latitude. This makes plotting on a chart very easy, because your scale along the vertical is a constant on any and every chart, and it directly corresponds to both position and distance (which are the same when you're talking latitude) if traveling due North or due South, and you can plot movement and objects very fast and very accurately using this ancient system. You can change charts (from small to large scale), like approaching land from blue water, and the units never change.
Just like shooting you don't need to do any math in your head unless you are converting it to another unit (like statute miles) because you're not familiar.
8kts or about 9Mph is pretty much the speed of a no-wake zone, and is a very typical approach speed. As has been mentioned, a ship needs to make way to be able to maneuver. The slower the screws the slower it will respond. There is a happy medium, and it's probably somewhere between eight and ten Kts depending on the vessel.
That's the very basics.
... 
he gets it.
