Single Versus Multi-Function Ships

Well, I didn’t want to do this but this is one of those topics that just keeps coming up and people just keep getting it wrong.  We’ve addressed it repeatedly in previous posts and comments but I guess it’s time to pull it all together, again, for the benefit of the newer readers who have not thoroughly perused the archives.  Huh?!  Not thoroughly perused the archieves????  You should be reading the archives every day!  The accumulated wisdom of the archives dwarfs the imagination.  But, I digress …

So many people want to cram every capability they can think of onto every ship built.  They claim that every ship should be able to do every task because, well …, you just never know what situation will arise.  Multi-function allows greater flexibility, they say.  We don’t have enough ships so they should all be as capable as possible.  A little extra equipment doesn’t really cost all that much more.  And so on.  The arguments are seductively reasonable, at first glance.  For example,

-          That helo flight deck only adds some flat empty deck – it wouldn’t cost much money.

-          Those anti-ship missiles don’t take up much room – it wouldn’t cost much money.

-          That larger radar array just doesn’t weigh that much more – it wouldn’t cost much money.

-          That hangar is mostly empty space – it wouldn’t cost much money.

-          That [non-existent] 155 mm naval gun is more powerful – it wouldn’t cost much money.

-          Those extra VLS cells aren’t that much bigger – it wouldn’t cost much money.

-          That sonar might come in handy– it wouldn’t cost much money.

The problem is that all those items that wouldn’t cost much money add up.  They add up to unaffordable ships which means a smaller fleet.

Some of you are already pounding out contrary replies and part of it is a lack of understanding of the basic concepts.  So, before we proceed any further we need to define single versus multi-function.  You wouldn’t think we’d need to but most people don’t understand what each means and what the difference is.

Definition - Single function does not, literally, mean only one function as so many of you sea lawyers seem to think.  If that were true, a single function ship would have an engine and nothing else because that would constitute its single function.  Well, that’s ridiculous!  So, obviously, a single function ship must have more than one function.  Huh?  Well, then, what is a single function ship? 

A single function ship is one that is built with a single, primary function that dictates all of its design characteristics like size, shape, speed, weapons, sensors, etc.  The key concept is that the term ‘single function’ refers to a single PRIMARY function.  Nothing about that definition precludes a lesser, secondary function as long as that secondary function does not negatively impact the primary function and does not significantly impact the overall cost.

For example, the pure AAW ship that also has a 5” gun for a secondary anti-surface function is, potentially, a reasonable addition since it doesn’t impact the primary function or the cost to any significant extent.  On the other hand, the pure AAW ship that has an ASW fit of sonar, towed array, helo, flight deck, hangar, and torpedoes has its size and cost significantly increased and the resulting increase in size negatively impacts the AAW function by making the ship a bigger  and more radar-reflective target.

This leads us, then, directly to the definition of a multi-function ship.  A multi-function ship is one which has, or attempts to have, multiple primary functions.  The problem with, and defining characteristic of, a multi-function ship is that the multiple, co-equal functions compete for space, funding, training time, and mission assignment and, inevitably, they all suffer – none function as well as they could.  Thus, the multi-function ship is, inherently, the inept jack of all trades and master of none.

The Burke is an example of a multi-function ship.  On paper, the Burke is a combination anti-air (AAW), ballistic missile defense (BMD), anti-surface (ASuW), land attack, and anti-submarine (ASW) ship.  In reality, the only mission that it is good at is AAW and, likely, not even that because the other functions take away from the AAW training time and make the AAW function less effective.  Seriously, does anyone believe that the once a year scripted ASW exercise makes the Burke an effective ASW platform?  For that matter, would anyone seriously risk a multi-billion dollar Burke playing tag with a submarine?  If not, why waste the space and budget on and ASW function?

Let’s now consider some of the arguments that are made for multi-function ships.

History – Yes, history is cited as an argument for multi-function ships.  Many people erroneously make the argument that ships have always been multi-function and that this is the norm and should, therefore, continue to be so.  Of course, this is flawed reasoning on the face of it but, setting the logic issue aside, let’s consider some of the historical examples. 

A commonly cited example is the battleship which was used to provide land attack, anti-air support for carriers, and anti-surface warfare.  That’s about as multi-function as it gets, right?  Well, the reality is that the battleship was designed for one primary task and one only – anti-surface.  The battleship was built to sink other battleships.  Any other capability was either fortuitous, like land attack, or an adjunct to its primary role, like anti-air.  Anti-aircraft capability was not designed into the battleship so that it could act as an escort to carriers – it was designed in as a self-defense capability to allow the battleship to survive long enough to perform its primary function of sinking other battleships.  That the battleship proved to be a superb anti-air escort platform was, like land attack, fortuitous.

The other commonly cited example is the Fletcher class destroyer.  People claim it could perform anti-air, anti-submarine, and anti-surface warfare.  The reality is that the Fletchers were designed to perform one primary function – attacking enemy battle lines with their heavy torpedo fit.  The other capabilities, as with the battleship, were present to allow the destroyer to survive long enough to perform its task.  Convoy and task force escort was a secondary function which accounts for the ASW fit.  This was an acceptable example of a secondary function because the ASW fit of the time was pretty minimal and did not impact the primary function or cost to any significant degree.

We see, then, that most ships have been single function.  It is the failure to understand what their primary design function was that leads people to think they are multi-function.

Flexibility.  This is the most seductive argument and the most wrong.  Flexibility is only useful if the functions can be executed competently but the reality is that no ship can be outstanding at more than one thing.  The training time just isn’t there to be good at more than one function.  Consider the Burkes – designed as anti-air warfare platforms, they also have anti-submarine capability.  What great flexibility!  Except that the Burkes never train for ASW and, therefore, are terrible at it.  It’s not flexibility if you can’t do the job competently.

Flexibility comes not from having a single ship with multiple capabilities but from having several ships, each with their own capability.  A single ship can only be in one place at a time and can only perform one task at a time – that’s the opposite of flexible.  On the other hand, several single-function ships can be in several places at once, each performing their own function extremely well.  That’s true flexibility.

Should I send that Burke out to chase a submarine or keep it with the carrier to provide AAW protection?  That’s not flexibility, that’s rigidity.  I’m forced to abandon one necessary task in order to accomplish the other.  Conversely, with multiple single function ships I can send an ASW ship to chase the sub and still keep a pure AAW ship with the carrier.  That’s true flexibility – the ability to meet all the required missions.

Resupply.  This one is specifically for helos, flight decks, and hangars.  Every ship needs a helo for resupply, the argument goes – they’re mandatory and we could not resupply without them.  However, everyone seems to have forgotten that we kept several thousand ships supplied during WWII without once using a helicopter!  This is just pure naval laziness and the cost is enormous.  A flight deck and hangar add around 130 feet to a ship along with associated weapons magazines, maintenance shops, spare parts storage, extra fuel, berthing for the helo pilots and maintenance crews, etc. and for what? – a little bit of convenience?

What If.  Many people make the argument that we should add all manner of extra equipment and functions because you just never know what situation a ship will find itself in.  The problem with this argument is that it has no bounds.  You can always come up with another ‘what if’ that requires yet more equipment and more functions.  This is the fast track to unaffordable.

The ‘what if’ argument is, essentially, the ‘desirable’ versus ‘mandatory’ argument.  Lots of things are desirable, and even useful, but if we built ships that had everything that was desirable then every ship would have a full carrier flight deck, 16” guns, Aegis/AMDR radar, full ASW suite, well deck, troop and vehicle storage, landing craft, and several hundred VLS cells and it would cost several trillion dollars – and we’d have a fleet consisting of just one ship because we couldn’t afford a second ship.  Similarly, if every soldier carried everything that was desirable in combat they wouldn’t be able to walk under the weight of the load.

The ‘what if’ argument is also the argument of fear and mental insufficiency.  We want every ship to have every capability and function because we’re afraid to accept any risk.  In the real world you build to the standard of reasonableness and accept the risk of the unreasonable.  Determining the standard of reasonable requires making informed decisions about the likelihood of threats and risk.  Too many people lack the mental capacity to make such assessments because, inevitably, they lack the totality of data needed to make a 100% certain, safe decision.  Lacking total data, they fall back on wanting all functions for all platforms.  That way, they don’t have to make difficult decisions.  The truly accomplished naval designer assess the likelihood of threats and risk and then designs for the most likely and reasonable scenarios – all on the basis of incomplete data and knowledge about the threats.  We just can’t know every trick China has developed.  Some people cringe in fear and develop massive, multi-function ships while others make their best judgments based on the data that’s available and then design optimized, single-function ships to deal with the anticipated threats.

The problem with the ‘what if’ approach is, again, that it is unaffordable.

Other Navies.  This, too, is a common argument.  Other navies build multi-function ships and they can’t all be wrong so we should, too, proponents claim.  Unfortunately, consensus does not necessarily equate to correctness.  The pre-WWII consensus among countries was that the battleship reigned supreme.  Of course, all of those countries were quickly proven wrong.

Other countries/navies are severely budget limited.  If you can only build a few ships then it’s only natural that you would try to cram as many functions into them as you can.  That’s not good design, it’s budget-limited design.  The US, in contrast, has the luxury of building as many ships as we want - provided we make wise decisions and don’t buy Zumwalts, Fords, and LCSes.  Thus, we can afford to build single function ships and lots of them.

I think that covers the major arguments for multi-function ships.  Now, let’s look at the arguments for single-function ships.

Cost.  Because single function ships are, by definition, smaller and ‘simpler’ than multi-function ships they are inherently cheaper.  Given the cost of multi-function technology the cost savings is generally going to be substantial. 

Consider the case of the Burke.  If we stripped out every function but AAW we’d remove the flight deck, hangar, shops, sonar, and towed arrays.  We’d reduce the crew by 50+.  The ship would be around 130 ft shorter.  What do you think the resulting ship would cost?  My guess is the new, single function AAW escort would cost around $750M compared to the current $2B+.

If we stripped out everything but the ASW function we’d wind up with a really cheap ship by comparison!

Conceptually, we could get 2-3 single function ships for the cost of 1 multi-function ship.

Numbers.  Because of the cost savings we just noted, we could afford a larger fleet – at least twice as large, if not more.

Flexibility.  This is the counterpart to the flexibility argument discussed above.  Several single function ships allow us to operate in several places at once – an immense advantage over a multi-function ship that can only be in one place at a time.  As we noted, this is true flexibility.

Competence.  Because they only have a single function, such ships would train exclusively for their function and would be extremely competent due to that focus.

Size.  Single function ships are inherently smaller which offers advantages.  In addition to cost savings, smaller ships make for smaller targets and are, thus, more survivable.  Smaller size also means quicker construction which allows for faster replacement due to wartime attrition.

Loss Impact.  Being smaller and cheaper, single-function ships cause less impact on the overall fleet capability when lost.  When you lose a multi-function ship you lose multiple functions.  For example, if we lose a Burke playing tag with a submarine we lose an ASW ship, an ASuW ship, a BMD ship, and an AAW ship, all in one.  That’s a huge price to pay, operationally and financially, for the loss of a single ship.  Conversely, if we lose a single function ASW ship we lose just an ASW ship – nothing more.  What’s more, it’s cheaper and quicker to replace a single function ship than a multi-function ship.

Optimized Design.  Having only one primary function, a ship can be exquisitely optimized for that function.  The LCS, for example, will be a poor ASW ship even with a working ASW module because the ship, itself, isn’t optimized for ASW.  The machinery is not acoustically isolated.  The hull can’t support a sonar.  The engines are loud, acoustic beacons.  And so on.

Risk.  When platforms get too expensive they become unusable because no sane commander will risk them.  How do platforms get too expensive?  - by making them multi-function.  As we’ve noted, a Burke is too expensive to risk playing tag with submarines.  A Ford is too expensive to risk penetrating enemy waters.  Thus, by being too expensive, multi-functional ships are unlikely to be used for the very missions they’re designed for!  Conversely, smaller, cheaper, single-function ships can be freely used as intended because they can be replaced and the loss of individual ships has minimal impact on overall fleet capabilities.

We see, then, that multi-functionality leads directly to increased costs, decreased numbers, and poor execution of all the functions.  We need the exact opposite of multi-function.  We need to build platforms not with the maximum that we can fit in them but with the minimum that allows them to execute their single, primary function and execute it supremely well.