Basic stuff out of the way first. As you know, overheat speed is capped at 70% for all
ships, and when you reach that cap depends a lot on the performance of your Engys.
If you don't understand how the cap works, then go read Adalbert's ability guides:

https://fm.en.navyfield.com/board/view.asp?Num=84358&Sort=D07

Most notably, look at section 8E of that guide, it gives a formula as to how Engys
affect your overheat ratio and how they stack with each other. As each ship and
engine combination has a different natural overheat ratio, the remainder that you
need in order to fill the rest is also different for each ship, so different ships will hit
the speed cap at different times.

Since the math may seem a bit convoluted to some people, I decided to post a rough
general guideline to how many Engys at what performance levels are needed in
order to completely hit the speed caps on certain ships. Do note that due to the fact
that the numbers round down, there are cases where you don't need to completely
hit the 70% speed cap; for example, on a 28-knot ship, the speed cap would be:

28 * (1.7) = 47.6 knots

Since it rounds down, that final 0.6 knots is useless, so to hit the speed cap at 29
knots, all you really need is 68%. But to hit the speed cap at any base speed with no
questions asked, 70% is the optimal ratio to reach.

I've done the calculations for each ship based on two factors:

1. How many Engys you have, between one and five
2. How good those Engys are, between grades D and SS

The first factor is fairly self-explanatory. If you have more Engys, your overall
performance increases, but you also get diminishing returns with more Engys, by a
factor of a square root, as noted in Adalbert's guide. So, in the most general case,
you will have three or four Engys; if you only have one, then you'll need either a
miracle or a lot of money to hit the speed cap successfully, or you could just buy a
second and maybe a third Engy.

The second factor is also sort of self-explanatory. The better each individual Engy is,
the better your overall performance. But since there are lots of factors to account for
here, I'll just do a general listing of broad categories for the grades.

Do note that my calculations assume that all of your Engys are symmetric (that is, all
of them are exactly the same); if you have Engys that have different bases, or not
the same amount of vets and experts, or only one of them is boosted, then just find
the grade that your Engys would most likely fall into as a whole; that is, take the
average performance level of your Engys, and find the grade that they would best fit
into.


--------------------------------------------------------
Grade D: "Put me out of my misery :(" Engys
--------------------------------------------------------
120 recruits remaining, 50 vets, +10 unboosted

This grade would generally define Engys belonging to either players who play
completely for free, or don't know the importance of Engys. As you can surmise, they
wouldn't perform very well even if you had them in spades, at least until very high
levels. This will be the general bare-minimum control group for hitting the speed cap,
since they will hit it last out of all the groups. So, if you find yourself in this group,
time to fork over some dough.


-----------------------------------------------------------
Class C: "I like to not have crappy stuff" Engys
-----------------------------------------------------------
50 recruits remaining, 80 vets, +11 unboosted

This is something of a step up, but again, as you can see, it best applies for someone
who does not have the monetary means to maximize the performance of their Engys.
In general, this would apply to players who know how the game works in general,
but again, either can't or won't spend money on their crew to max out their
performance.


--------------------------------------------------
Class B: "I like to be competitive" Engys
--------------------------------------------------
20 recruits remaining, 100 vets, +11 boosted

This would constitute the bread-and-butter Engy that most experienced players use;
they pick out the most reasonable base above +10 that they can get, and use
money to maximize its performance without going overboard. Except for beta-age
Engys (which are mainly on the decline nowadays), these are among the most
common types of Engys out there currently.


-------------------------------------------------------------
Class A: "I like to be REALLY competitive" Engys
-------------------------------------------------------------
0 recruits remaining, 105 vets, +12 boosted

Now we're starting to get near the zone of overkill, but don't quite enter it. This
grade generally defines people who don't spend money outside of their limits, but
also want to be serious about their crew. +12 base Engys are quite hard to roll
(unless you use macros), and keeping your vets too far above 100 isn't something
that can be easily done. This grade isn't really that much above B, and its main
purpose in this guide is to illustrate the difference that one extra point of base
makes.


----------------------------------------------------------------------------
Class S: "I have nothing better to do with my money" Engys
----------------------------------------------------------------------------
0 recruits remaining, 150 vets, Elite boosted

This is where you actually enter the zone of overkill, and well beyond. As 109 is the
limit to which you can buy vet items for your sailors, going above that requires expert
burning to a degree that could waste quite a bit of money depending on your luck.
It's generally not recommended to burn money to get Engys up to this point, since
class A is the most feasible point to reach, but if you have plenty of money to burn,
then be my guest.

------------------------------------
Class SS: "slayer6 lol" Engys
------------------------------------
0 recruits remaining, 40% vets, +11 boosted

Got hax? This class of Engy isn't listed here because there are actually enough
people out there for this data to matter, it's just here for fun. Let's say that, by some
uncanny luck, hax, mad money burning, or other method, you're able to keep vetting
your Engys up to the 40% allowable in the game. So, what you would get is
something that would let you run 86 knots in a Z99.

Note that, for time conservation and laziness purposes, I've only done analysis for a
maximum of three SS class Engys, rather than five.

--------