- 2 Pump Ships -
Ships
mounting 2 pumps seems to have gained popularity in recent years. The
allocation of offensive to defensive units has been left to captain preference
for the vast majority of the history of the hobby. For the most part, captains
have historically chosen to use 1 pump and the rest guns. To my observation,
the recent trajectory of relative increase in multi pump ships started in 2009
when Jeff put 2 pumps in his IJN Mutsu (Nagato) in order to combat the relative
effectiveness of the USS North Carolina. At that time the North Carolina with
triple stern guns was widely considered the best ship in the hobby and there
were a number of North Carolina captains with highly functional ships that were
causing buoyancy problems especially for the Japanese battleships. It is fairly
well established that putting damage into the flared bow is highly effective at
forcing these ships to become unable to effectively maneuver and sink. As I write
this article, the Nagato remains the prime example of a ship that is most
commonly set up in this fashion, however other ships have also benefited from
and used 2 pump setups. The larger ships (Richelieu, Bismarck, Vanguard,
Yamato, Iowa) are able to be more competitive with 2 pumps in that these very
large ships can more safely take damage in an otherwise easy to hit target, but
also are able to sacrifice a smaller percentage of total offensive capacity in
order to use another pump. For the most part, only a hand full of captains even
in recent years have used 2 pump setup in class 5 ships. It is much more common
in class 6 ships. In class 4, it seems to be too much of an offensive sacrifice
to mount 2 pumps, though being able to split a 4.5 unit ship into 3.0 guns and
1.5 pumps could be viable.
Due
to the increasing popularity of using 2 pump ships, the performance differences
and how they should function and be balanced are being called into question.
The intent of this article is to try to use data to better understand how these
ships are performing. I have been able to compile the scoresheets from Nats 2015-2020. I included each
complete battle by a captain in a single ship (2 sorties completed or sunk in
the first or second sortie) as a single data point. Campaign, night battle,
one-on-ones, challenge battles, and ships that withdrew from combat were
excluded. There were 755 data points across 6 years.
Popularity
“How
popular are two pump ships and is there change over time?”
Of
the 755 data points spread over 6 years, 126 (16.6%) were two pump ships, 629
were 1 pump ships. As a function of time, there seems to be relative stability
in recent years without a clear trend.
“What
ships are being fit with 2 pumps?”
As
a percentage of all ships battled in this time period, a 2 pump Nagato has the
more entries than any other ship and constitutes 5% of all of the ships at
Nats. Nagatos have used 2 pumps 69% of the time and 1 pump 31% of the time. QE
has the 2nd most entries but it is less popular to battle a QE with
2 pumps than with 1 pump. The Bismarck was used some with 1 pump, but mostly
with 2 pumps. The very large ships with 8 battle units were exclusively used
with 2 pumps in this data set. There was only one class 4 ship to use 2 pumps.
“Are
certain captains heavily influencing the data?”
Interestingly
enough, roughly half of the 2 pump use has come from just 5 captains (60 out of
126 entries). Only these 5 captains have used 2 pump setups in multiple Nats.
Tyler used two pumps 23 times (5 in Nagato – one Nats, 17 in QE – 3 Nats), Mark
14 (all Nagato), Jeff 10 (5 Nagato, 5 Yamato), Will (all Jean Bart over 2
years), Carl (4 Rodney, 2 Yamato). Additionally, 3 captains account for 24 of
the 39 two pump Nagato entries. All other captains not listed below used a 2
pump setup for just one Nats event. Tyler alone accounts for 18% of all of the
2 pump ships used spread across 4 of the 6 Nats.
“Are
the Axis or Allies the biggest user?”
The
axis are more prone to use 2 pump setups, 19% of the time vs the Allies’ 14%.
Though in raw numbers this is only 8 more occurrences (ie, one captain at 1 and
½ nats).
Damage
Taking
“Does
having 2 pumps make it less likely to sink?”
“How
much more damage can a 2 pump ship take?”
I
have averaged the holes a 2 pump ship takes in a battle regardless of if they
sink or not, how many they take when they sink, and how many they take when
they don’t sink. To sink an average 2 pump ship it takes 103 holes, vs the 76
holes it takes to sink a 1 pump ship. 27 additional holes is roughly a 35%
increase. It would seem counterintuitive that it doesn’t double or even come
close to doubling damage threshold of sinking.
Another
useful way to view the data is to consider each battle as an individual entry
and normalize the data. This allows us to make a graph that can aid in
understanding the numbers. The standard deviation is quite wide, meaning that
the disparity for all ships is very massive, the difference between high and
low achieving ships regardless of if they sink or not and regardless of how
many pumps they use is high. Interestingly enough, the degree of disparity, ie
the variability in how many holes it takes to sink a 2 pump ships is slightly higher
as compared with 1 pump ships which is slightly more consistent.
“What
if you exclude very lightly damaged ships”
To
adjust for light damage sinks, I have excluded all ships that sank with
less than 50 above and/or 20 below and ran the data again. This is intended to
remove the lightly damaged outliers. Regardless of number of pumps, it is
surprisingly common for ships sink with light damage due to captain error, poor
ship design, bad luck, or systems failure. After the adjustment, the number of
holes it takes to sink a ship expectedly increases but the absolute disparity
remains near identical, 124 holes to sink a non-lightly damaged 2 pump ship vs
99 holes to sink a non-lightly damaged 1 pump ship. The 25 holes however
translates to a lesser relative difference, in that having 2 pumps only
increases survivability by 25% compared to 1 pump ships.
“What
if you compare within a class?”
Similar
Results are found if Class 6 (Excluding Vanguard, Iowa, Yamato) and Class 5 are
compared amongst themselves. To sink a class 6 ship with 2 pumps takes 126
holes vs 102 holes for a 1 pump ship. To sink a class 5 ship with 2 pumps it
takes 121 holes vs 104 holes for 1 pump ships. Comparing ships by class
maintains the relative risk reduction of sinking with adequate damage by only
25% if using 2 pumps. It should be noted that light damage (<50 above and
<20 below) was similarly excluded in this series.
“What
if you compare a ship only to itself?”
The
QE was used because it has the broadest data set (most captains, several
entries with 1 pump, several with 2 pumps). This is raw data only, light damage
and light damage sinks are included. The limitation is that only 2 captains
used a 2 pump setup. A few interesting findings are that Andy’s 2 pump QE sank
with less damage and more often as compared to when he ran 1 pump in it, though
the damage taken when he didn’t sink was higher in the 2 pump setup. The rate
of sinking is 35%, identical for 1 and 2 pump ships. The average damage taken
to sink the 2 pump setup in this ship was 102 as compared to the 88 for the 1
pump setup. The difference of 14 holes translates to 16% increase in damage
required to sink with 2 vs 1 pump. The standard deviation of holes taken to
sink is a whopping 28, indicating a very large disparity in this data. Bob’s,
Andy’s and Brandon’s one pump setup all beat the average for the 2 pump setup when
they sink. Like wise several captains/ships are on the very low side of the
spectrum. When the data for all ship/captain combinations is normalized (see
graph) it becomes very apparent that all QE’s are not created equally.
I’ve
also divided the data for each battle to have its own data point rather than
using the average and sorted by sinks/floats for the QE and compared average
holes for 1 vs 2 pumps. The data would indicate that a QE’s experience if not
sunk is identical with 1 or 2 pumps, average holes are 74 regardless. However,
if 2 pumps are used they will take an additional 24 holes to sink as mentioned
above. The charts below show the data normalized. Again, with 1 pump or with 2
pumps there is a massive disparity in damage required to sink but generally
speaking fewer really lightly damaged sinks for 2 pumps though a cluster around
the mean is clear. Again you can see that several 1 pump QE’s out perform some
of the 2 pump QE sinks.
“Does
the likelihood of sinking or surviving with light vs heavy damage change based
on number of pumps?”
As
alluded to above, a way to interpret data that seems to generally be
informative is to try to group ships by light vs adequate damage. The intention
is to remove lightly damaged outliers from the data. I approximate that most
class 4 and higher ships should be able to in most scenarios survive less than
50 above and 20 below holes. For the purpose of sorting data, I categorize
these as “easy sinks” if they don’t meet these criteria and sink and “easy
float” if they don’t meet these criteria and don’t sink. Ships that sink with
at least 50 above and/or 20 below are “tough sinks,” meaning that there was
less likely a system failure or poor design alone that lead to the sinking of
the ship, and similarly “hard float” if they took adequate damage but did not
sink. Of the 126 ships with 2 pumps, half of them float despite taking adequate
damage, whereas 29% of 1 pumps did so. As far as light damage, 5% of the time a
2 pump ship takes to the water it sank with light damage, whereas 10% of the a
1 pump ship goes to battle it will sink with light damage.
Conclusions/Discussion:
Regardless of the various criteria applied (class of ship, all
data, light damage excluded), it takes roughly an extra 25 holes to sink an
average 2 pump ship as compared to a 1 pump ship. At maximum this is 35% more
damage/holes, but in reality it is closer to 25% more damage when lightly
damaged ships are excluded. This number is really important in that it is
indicating that adding a pump no where near doubles damage taking capacity.
For all ships regardless of if they sink or float, the
average holes a 2 pump ship takes is 91, as compared to 62 for a 1 pump ship.
The difference being 29 holes. Generally speaking, when a 2nd pump
is added, a 50 round stern gun is removed. At most 30-50% of an average sten
gun shots will make a hole in a target. Therefore, by removing a gun and adding
a pump, you are in effect taking on average 29 holes into your ship and
removing 60-100 holes of damage (50 rounds x2 sorties) to the other team. For
the average captain this is a significant net negative in terms of hole scoring
alone. However, I believe a high performing captain can get over 50% of a stern
gun or stern sidemount to hit and if they can otherwise be effective on the
water and not sink, in this situation may just make up for the holes they take
in return.
2 pump ships are not unsinkable, but do sink less often. 22%
of the time a 2 pump ship goes out to battle, it gets sunk. This compares to
31% of the time for a 1 pump ship. Improved survivability is not unsinkability,
though the relative likelihood of sinking is cut by 1/3. It is very important
to realize that adding a pump doesn’t decrease your chance of sinking by 1/2 as
could otherwise be theorized. The disparity actually shrinks massively when
excluding lightly damaged ships, as 17% of 2 pump ships sunk vs 21% of 1 pump
ships sunk, which is really only cutting the relative risk of sinking by 25% by
adding a 2nd pump.
2 pump ships are less likely to sink with light damage. 5% of
the time a 2 pump ship goes to battle it sinks with light damage as compared to
10% of the time for 1 pump ships. This is the category with the larget relative
benefit gained by using 2 pumps. By adding a 2nd pump you decrease
the likelyhood of sinking with light damage by 1/2. I would guess that a fair
bit of this is having a larger margin of error for pump system failure.
Having 2 pumps appears not to be a deturrent to getting shot.
I’ve heard that some captains believe it isn’t worth engaging with 2 pump ships
because damage dealt to them is less likely to cause a sink, so they should
just be avoided. And as already stated, on average a 2 pump ship will collect
29 more holes than a 1 pump ship in any given battle. The data also indicates 2
pump ships survive with light damage only 27% of the time, where as 1 pump
ships take light damage more often, 39% of the time. I would expect that some
of this may be due to a higher level of agression 2 pump ship captains feel
that they can safely battle with.
The disparity between different captains and different builds
is highly appearant in the QE specific data set above. It would appear that some
captians can be just as tough or better in a 1 pump QE as a 2 pump QE. And some
1 pump QE captains are outside of 1 standard deviation below the mean with
damage when they sink. This argues to the point that I often make, is that the
captain’s ability to build and battle are far more important than the ship
selection. There are certainly ships that are inherantly more powerful than
others, however the disparity in captain ability is much more broad than the
disparity in ship power. Having battled on both Axis and Allied fleets (at Nats
I’ve battled Axis 5 times: Derfflinger, Nagato x4, and Allied 5 times:
Minneapolis, Bob’s QE, Barham x3), in my opinion the Axis/Allied disparity of
powerful ships is balanced.
Limitations and things that would seem true but are difficult
to conclude from the data.
Various factors seem to be true but can’t be measured by the
data alone. The challenge when a direct observation seems cleraly to be
pointing to a certain conclusion is that true causality can be more complicated.
The challenge in that is related to human bias, we tend to believe things we
see with our own eyes as we interpret them, even though we don’t have clear
reproducable evidence to support it. That’s where the data can help. Before
doing the math for instance, I would have figured two pumps make it possible to
take 50-70% more damage before sinking rather than the 25-35% the data
indicates.
Though there are 755 data points, there are certain
limitations due to the size and properties of the data set, especially if any
specific smaller subset is considered. Tyler is a lot of the 2 pump data (18%).
2 pump Nagatos are primarily 3 captains who I would consider to function highly
in any ship they bring, and 5 of the data points are a different captain drivng
said Nagato. As another example, Tyler and Andy account for all of the 2 pump
QE data points.
The data can’t describe how captains drive their ships. In
general I would expect 2 pump ships to be captained in a more aggressive way.
Also, I would expect that 2 pump ships are more likely to mauver better with
higher amounts of damage. The late stages of battle may be heavily influenced
by 2 pump ships that have a little more staying power. The damage/sinks they
cause are not going to show up in the data, but observations of how the water
is controlled may have different optics.
The 2 pump data is not only heavily influenced by a small
number of battlers, but I would also argue that the optics of 2 pump ships in
general are heavily influenced by what we experience pond-side, though data may
seem to indicate otherwise. For instance, I would expect that a fair number of
people didn’t realize there was a Kongo in 2018 with 2 pumps, even those at
that event battling against it. On the flip side, lot of the 2 pump Nagatos
have been Jeff’s builds, driven by Jeff, Mark, or Johnny. Most people who have
been on the water with them would recognize that these specific ships are very
highly tuned and the captains are higher performing regardless of ship.
Another valuable viewpoint is how 2 pump ships perform at
local events and regionals. There are a few specific issues with this that we
will not easily be discernable from this or any data set. One is that some
regionals allow for sunk 1st sortie ships to patch and come back in,
or some times have 3 sortie battles. Though I have access to it, using regional
battle data would be inconsistent with the way the rest of the data interacts
and as such was not used. Also, the way that battlers tend to play at regional
events is often more aggressive and probably would skew the data differently
depending also on how many battlers are at an event. Additionally, the optics
of a very highly tuned ship captained by one of the best battlers in the hobby
at a small regional battle for instance might lead to the view point that the
ship is too powerful, when in fact the actual issue is that the disparity of
building and battling skill is more exagurated at smaller events, when it feels
like you take a beating from said battler multiple times per weekend.
Part
of the subtle effectiveness of using 2 pumps actually comes from enhanced
offensive capability that results when exchanging stern firing guns for a
sidemount. A lower damage yielding gun is exchanged for a higher damage
yielding gun in addition to adding a pump. As I pointed out above, this may
actually lead to an average captain becoming net negative. Also in some ships,
specifically 3 turreted ships, using 2 pumps in exchange for trying to mount
more sidemounts leaves very few possibilities for reasonable gun setups. This
is especially true for the Allied class 6 ships, and it generally isn’t a
well-balanced setup to do this. The North Carolina is a great example of this.
The often discussed Axis/Allies disparity in which ships are naturally best
suited to use a 2 pump setup is in my opinion part of the inherent difference
between the Axis and Allied ships in general and has value in and of itself.
Its more interesting if there are different strengths/limitations that seem to
cluster by nation. In years past there was a commonly held view point that the
Axis were under gunned due to lack of triple stern gun ships. In more recent
years the discussion has shifted to the Allies feeling disadvantaged by trends
in the hobby due to the lack of fast ships that use stern sidemounts and ships
that can more naturally utilize two pump setups. Just as there was a response
to triple stern guns, there is likely a response to two pump ships that is
currently being under-utilized.
Again,
it is very important to realize that any specific ship or setup is only as good
as the person who built it and who is captaining it. Even within the data
above, there is a high level of disparity amongst 2 pump ships in how much
damage they take to sink. Something that I observe in the data that is
difficult to quantify is the high number of what I would consider top battlers
in the hobby also opting to use 2 pump ships. All of the captains who have used
2 pump setups in the data I have also seen in 1 pump ships over the 14 years I
have been in the hobby, and all of these captains I would also consider highly
effective battlers in any ship they bring. This gets back to optics. Highly
function captains are better able to get the most out of any ship build,
including 2 pump designs. And highly functioning captains seem to be seeking
advantages by using this design.
Tyler, 3/17/2021