Convoys..

Flight

LE
Book Reviewer
With the recent hullabaloo in the Persian Gulf seeing Andrew escorting convoys again I wondered how much had changed.

Uboats sank 2800 odd merchantmen in the Second World War though their average size appears to have been about 5,550 tons each. Taking figures from 2018 it appears that the average merchantman these days is at least 35,000 tons. And some clearly well north of 100,000.

Question is does this make it easier or harder these days to defend a convoy? One would presume that large merchantmen would be harder to sink, but far easier to locate even in the North Atlantic. The ebbs and flows of the Battle of the Atlantic seemed to follow the success of GCCS or B Dienst, though we can probably assume that a convoy would be impossible to hide from satellite recon and the like.

I'd assume modern ships are faster, container ships in particular. Though the likely escorts are not necessarily faster than their WW2 counterparts.

I suppose my assumption here is that even a well escorted convoy would pretty much be a sitting duck against determined attack by SSNs or fast air...

What would a modern tub purely designed for convoy escort look like these days?
 
I'd assume modern ships are faster, container ships in particular. Though the likely escorts are not necessarily faster than their WW2 counterparts.

I suppose my assumption here is that even a well escorted convoy would pretty much be a sitting duck against determined attack by SSNs or fast air...

What would a modern tub purely designed for convoy escort look like these days?
Given range of radar and sonar, sneaking up would be a problem.
Sanitising a sealane via sonobuoys and air patrol would see a convoy through, methinks.
AA destroyer like HMS Dragon could deal with airborne threat, hopefully.
 

Mattb

LE
I don't think that a 300,000 tonne container ship is going to be hugely easier to locate in the middle of the ocean than a Liberty Ship is.
 
So a series of Tu-22 upgrades were undertaken. This seemed to work, except for one problem. Three times in the last three years one of these upgraded aircraft have crashed. The latest accident, at the end of 2019, involved an engine failure on takeoff. The pilot promptly sought to make an emergency landing. The pilot did not want to risk turning around and making it back to the airbase because there residential areas near the base. Instead, he found a large open area ahead of the aircraft and made a successful belly landing. The landing gear would not likely work landing in a field and the belly landing did minimal damage. The problem now is to make repairs and get the Tu-22M3 back to base. The two other accidents were less successful and led to the destruction of the aircraft and the deaths of crew members.

 

lert

LE
Comparing the current situation in the Gulf to the North Atlantic is probably apples and oranges to be fair. Though the problems on both sides of the equation remain the same, regardless of the passage of time. One side has to find and kill the merchies, the other has to hide them and stop them getting sunk. It's worth remembering that although there were an awful lot of merchies sunk in WWII, there were an awful lot of U-Boats sunk too. Which demonstrates, I suppose, just how fine the line between advantage and disadvantage is for both hunter and hunted.

At the risk of winning this years prize for stating the bleedin' obvious, ISR is an order of magnitude harder for an adversary trying to close the Atlantic than for the IRGC Navy. All they have to do is have a dekko out the window, the Russians (let's call a spade a spade) are looking for the proverbial needle in a haystack. While space based surveillance does make that easier, it's not the panacea some imagine it be. Near real time acquisition and targetting is very different from real time, as well as being state of the art. I'm genuinely not an expert but let's say a convoy of modern carriers is mooching along at 25kts. And let's say it takes our adversary 90 minutes to turn detection of a ship wake into an actionable set of target co-ordinates. In that 90 minutes the 'target' is 37 nm away. Or anywhere in a circle of 3,800 odd square miles. That's before you launch your strike. Truly persistent monitoring from space is beyond state of the art right now, so in reality it may be several hours before you reacquire that target. So an air launched strike, even with Vlad's new super-duper Russia stronk HSMs isn't an absolute given.

Of course, there are other ISR assets that are truly persistent. In a shooting war then I'm not sure just how survivable an MPA would be. Either getting round the top of Norway or beyond. That, realistically, leaves Ivan with his (admittedly increasingly capable) SSN fleet. Here's where it gets interesting though. When your means of attacking a merchant convoy is to all intents and purposes a strategic asset, just where does your risk/reward line lie? Cue an air strike? Escorts know there's an SSN in the area, and it's squawking. Risk an attack? See above. And all the escorts have to do, for the win, is keep that sub away from the convoy. Not kill it, that's a bonus. Just keep it out of range.
 

Flight

LE
Book Reviewer
Suspect we'd have to be a bit short of other things to do in order to spare a Type 45 for convoy work... And don't assume I'm only talking about the Atlantic here... Any overseas deployment will presumably need merchantmen to ship stores commercially or stuft... I'm guessing the Atlantic would be the least of a convoy's worries given choke points and whatnot.

Can't see that these massive container vessels are much use either... The largest only carries aout 50k tonnes, which is close to handymax and not terribly far above the average. Though admittedly the fast liners in WW2 did happily steam across the atlantic unescorted and generally unbothered by Uboats due to their speed at about the same rates as current container ships. Not that we could guarantee a container port wherever the natives need a good thrashing. Or that a container port if available would necessarily have the capacity.

I presume at some point that has been wargamed or preferably tested with military exercises. I also presume that on our various jollies around the world the baggage train has been relatively secure without having to resort to convoys though looking at the amount of commercial shipping required for ops in the Med during WW2 one of the things which struck me was that each torpedo would take out at least 7 times as much... stuff... as it did back then.

Potentially each asm too as the Atlantic Conveyor didn't particularly like it's exocet...
 

Mattb

LE
Suspect we'd have to be a bit short of other things to do in order to spare a Type 45 for convoy work... And don't assume I'm only talking about the Atlantic here... Any overseas deployment will presumably need merchantmen to ship stores commercially or stuft... I'm guessing the Atlantic would be the least of a convoy's worries given choke points and whatnot.

Can't see that these massive container vessels are much use either... The largest only carries aout 50k tonnes, which is close to handymax and not terribly far above the average. Though admittedly the fast liners in WW2 did happily steam across the atlantic unescorted and generally unbothered by Uboats due to their speed at about the same rates as current container ships. Not that we could guarantee a container port wherever the natives need a good thrashing. Or that a container port if available would necessarily have the capacity.

I presume at some point that has been wargamed or preferably tested with military exercises. I also presume that on our various jollies around the world the baggage train has been relatively secure without having to resort to convoys though looking at the amount of commercial shipping required for ops in the Med during WW2 one of the things which struck me was that each torpedo would take out at least 7 times as much... stuff... as it did back then.

Potentially each asm too as the Atlantic Conveyor didn't particularly like it's exocet...
Worth noting that we have a fleet of ships for the purpose of moving the Army about the place.
 

Yokel

LE
With the recent hullabaloo in the Persian Gulf seeing Andrew escorting convoys again I wondered how much had changed.

Uboats sank 2800 odd merchantmen in the Second World War though their average size appears to have been about 5,550 tons each. Taking figures from 2018 it appears that the average merchantman these days is at least 35,000 tons. And some clearly well north of 100,000.

Question is does this make it easier or harder these days to defend a convoy? One would presume that large merchantmen would be harder to sink, but far easier to locate even in the North Atlantic. The ebbs and flows of the Battle of the Atlantic seemed to follow the success of GCCS or B Dienst, though we can probably assume that a convoy would be impossible to hide from satellite recon and the like.

I'd assume modern ships are faster, container ships in particular. Though the likely escorts are not necessarily faster than their WW2 counterparts.

I suppose my assumption here is that even a well escorted convoy would pretty much be a sitting duck against determined attack by SSNs or fast air...

What would a modern tub purely designed for convoy escort look like these days?
I think a modern warship built for convoy escort would be the same as an escort type surface combatant designed for task group operations. Sometimes the high value units are merchant vessels. World War Two was long enough to design and build ships for the Atlantic and other theatres.

The smaller number of modern merchant vessels does make them more attractive targets but easier to defend individually.

NATO will be exercising protecting shipping across the Atlantic this year.
 

SamYeager15

Swinger
Container ships require a port containing cranes in order for their cargo to be unloaded. Am I missing something obvious as to why the harbour front of the ports where said cranes are located can't just be attacked as one of the first actions of any conflict? Especially since the proverbial stinginess of the Treasury will ensure that there isn't a ready supply of missiles to prevent this.
 

Flight

LE
Book Reviewer
The smaller number of modern merchant vessels does make them more attractive targets but easier to defend individually.
Compared to WW2?

Suspect the number has increased dramatically but will look into it. Did see that modern tonnage worldwide was in the order of 20 billion, whereas losses of 700,000 tonnes per month were considered disasterous back then. Which could be two ships these days.
 

Yokel

LE
Compared to WW2?

Suspect the number has increased dramatically but will look into it. Did see that modern tonnage worldwide was in the order of 20 billion, whereas losses of 700,000 tonnes per month were considered disasterous back then. Which could be two ships these days.
Yes but a World War Two convoy could be spread out over a number of miles, making it hard to protect individual merchantmen. These days a smaller number of vessels would need defending and could be afforded a much higher level of protection.

Protecting shipping is frequently a naval role - in the Strait of Hormuz, in the Red Sea, and in the NATO theatre.
 

Flight

LE
Book Reviewer
As far as I can tell the toal allied shipping available during WW2 was about 60 million tonnes. On average 5-6000 tonnes at the begining of the war and increasing slightly due to the number of Liberty ships produced during.

Still represents less than 30 a day docking at UK ports, and that is assuming every ship docked in the UK rather than being used for India and the rest of the empire. So a big over estimate.

Excluding all RoRo vessels (56% of all arrivals) and Dover entirely ( assuming entirely EU based)seems to be about 70-80 per day and vessel sizes of approx 60,000 tonnes. Though I've had to make some assumptions from the data.

Regardless there do appear to be both more vessels to be convoyed, and they contain ten times as much on average.

Possibly speed might help compared to ye olde convoys, some container ships are really quite fast, though everythng else seems to point to bigger and more difficult to protect.
 

Yokel

LE
The US Navy has practiced escorting merchant shipping across the Atlantic for the first time in over thirty years. I expect we will be seeing more of this:


In the eighties, the RN carriers sometimes took part in these exercises, with Sea Harriers (and AEW Sea Kings) for fending off Bears and ASW Sea Kings for 24/7 dipping in defence of the convoy.
 

Flight

LE
Book Reviewer
Be interesting to see the results of thirty year old exercises aimed at convoy defense. What percentage of merchantmen would have made it..

I've heard many old submariners complaining about the restrictions placed upon them in such, though they still considered anything that floats to be a mere target.
 

diverman

LE
Book Reviewer
Be interesting to see the results of thirty year old exercises aimed at convoy defense. What percentage of merchantmen would have made it..

I've heard many old submariners complaining about the restrictions placed upon them in such, though they still considered anything that floats to be a mere target.
And tales of RN submarines either getting into the middle of Russian surface warfare groups and photographing the keel of the one or the one about the RN sub getting into the middle of a US carrier battle group and firing a flare. many did not survive the aftermath.
 

Yokel

LE
And tales of RN submarines either getting into the middle of Russian surface warfare groups and photographing the keel of the one or the one about the RN sub getting into the middle of a US carrier battle group and firing a flare. many did not survive the aftermath.
What about submarines (non RN/USN/NATO) that were less quiet and had less well trained crews? Until the mid eighties the West had a considerable advantage in terms of quietening our boats.

The Soviet submarine forces would have taken heavy losses. A large part of NATO's efforts was to track all Soviet submarines in peacetime, and to have a plan to prevent a mass break out of Soviet SSNs into the Atlantic in the event of conflict.
 

bob231

War Hero
With the recent hullabaloo in the Persian Gulf seeing Andrew escorting convoys again I wondered how much had changed.

Snip

I suppose my assumption here is that even a well escorted convoy would pretty much be a sitting duck against determined attack by SSNs or fast air...

What would a modern tub purely designed for convoy escort look like these days?
I'll caveat this with that I am an engineer, not a Warfare officer, and I may have some of the details wrong. With that in mind:

1. Much depends on the threat. Top-of-the-line SSNs probably have rather better things to kill than merchantmen, especially given that a boat moving fast is detectable over much longer ranges than they used to be, so the time taken to return and resupply is much longer.

2. For low-level shore missiles and fast boats, "Anything with a Phalanx" will probably do you. You could augment this with more Phalanx and soft kill (decoy IR, chaff, etc) if you're not expecting really good Anti-Ship Missiles.

3. Anti-air missiles obviously allow you to defend at range but this should be measured against cost and resupply: a convoy ship with the capabilities of an Air Warfare Destroyer costs very nearly as much as an Air Warfare Destroyer! It also means you need the generation capability and auxiliary systems for high-end radar, which are large and complex.

4. Passive sonar isn't a realistic option given how fast and loud modern merchantmen are. If your enemy has submarines that can be easily placed on your routes (which pretty much guarantees you're going for choke point transits), you would need to speed along on active sonar. However, this is invalidated by:

5. Mines, the single and best means of closing any chokepoint at minimal cost and requiring minimal capability. This requires dedicated minehunting capability, manned or unmanned.

I've revised this a few times in writing it and can't really see a scenario where a near-peer or peer enemy decides the best course of action is attacking merchantmen first. Highly capable assets (air-launched or ground-launched anti-ship missiles, quality SSNs or SSKs) make more sense as weapons to use against our actual fleet. For choke points, the weapon of choice will remain mines until we develop a fast and effective means of removing them en masse, while in the open ocean the sheer increase in speed of modern merchantmen makes intercepting them significantly harder. The easier areas to attack - near ports - are also significantly easier to defend using existing ships.
 

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