Destoyer Trial Speed calculations

[snip]

Originally developed during N3, this process is still used. I've posted it here for those who wish to read the how of the process. A calculator for running this automatically is posted in the Ship Design Guidelines thread.

To calculate the speed attained by that ship on trials in smooth water, you can use the following equation:

To calculate the trial speed, first find the base bonus derived from it's light displacement, starting with what "band" the ship is in:
<=210: 6 knots
<=250: 5 knots
<=500: 2.75 knots
<=750: 1.5 knots
<=1000: 1.125 knot
<=1500: 0.75 knots
<=1750: 0.6 knots
<=2000: 0.5 knots
over 2000 tons: 0 knots

In each band, then divide the bonus for that band by the value of the light displacement divided by the upper limit of that band..

So for instance, for a 450t (light) dd, do this: 2.75 / (400/500) = the "base" bonus of 3.44 knots.

Then mix in the machinery modifier, which is simply the normal displacement percentage of machinery/0.6 (so that a machinery weight of 60% = 1), then multiply the base bonus above by that figure.

For one example ship:
Displacement: 250t
Mach %: 51.7 (or after divided by 100, 0.517)
Speed: 28.08

Base bonus: 5 / (250/250) = 5
Mach modifier: .517/.6 * = .861667

So the bonus = 5 * .861667 = 4.31 (rounded to 2 decimal places), or 4.5 (rounded to the nearest half knot), giving a new clean water optimal condition trial speed of 32.5 knots (using the half-knot rounded figure).