Seelöwe - let's discuss barges sunk by bombers

[Andreas]

Split from:

http://forum.axishistory.com/viewtopic.php?t=117160

.... It would be bad economy - and totally out of the Dowding spirit - to use the fighters for this purpose......... ...

If we are about to abandon this topic for a bit I think this is an important point to reiterate. Even if the fleets AA performance in terms of shooting down attacking fighters is in questions. I agree that strafing the barges would be far from the best use for British fighters.

I'd use high level bombing. Even near or not so near misses would do the bizzo on a barge.

All the best

Andreas

[fredleander]

.... It would be bad economy - and totally out of the Dowding spirit - to use the fighters for this purpose......... ...

If we are about to abandon this topic for a bit I think this is an important point to reiterate. Even if the fleets AA performance in terms of shooting down attacking fighters is in questions. I agree that strafing the barges would be far from the best use for British fighters.

I'd use high level bombing. Even near or not so near misses would do the bizzo on a barge.

All the best

Andreas

In September '40 the Bomber Command performed attacks against the tight-packed invasion fleet in the Continental ports for 23 days. Different sources state the German losses to have been 8-12 % of the fleet (within the German reserve margins...). With quite a few losses to the RAF. So how could they do large damage on a spread-out landing force...?

[LWD]

Well for one the AA fire from the ports was probably heavier and better aimed than that from the fleet would be. There is also the impact of bombing on the fleet. In at least one case from the Pacific a high level bombing atttack resulted in the Japanese convoy becoming disorderd and spread out. It was then pretty much destroyed by lower level attacks. High level attacks could also have the benefit of causeing the German fleet to burn up a lot of their heavy caliber AA ammo.

[RichTO90]

In September '40 the Bomber Command performed attacks against the tight-packed invasion fleet in the Continental ports for 23 days. Different sources state the German losses to have been 8-12 % of the fleet (within the German reserve margins...). With quite a few losses to the RAF. So how could they do large damage on a spread-out landing force...?

Er, no, they didn't. In September Bomber Command executed 6 major attacks on the Channel ports, beginning on the night of 10/11 September, then on the nights of 13/14, 14/15, 15/16, 17/18, and 20/21 September. The largest raid was on the night of 17/18 September when 194 aircraft were dispatched with 75 percent of them against the ports themselves (and only 187 aircraft reported bombing successfully). The second largest was apparently that of 15/16 September when 155 aircraft were dispatched, but including 43 that were sent against oil storage tanks at Antwerp. The smallest raid - possibly the first one - was 92 aircraft, the other three were all of "over 100 aircraft each."

So perhaps 800 to 900 sorties by Battles, Hampdens, and Wellingtons resulted in:

Lost: 2 T-Boot, 12 transports, 51 barges, 4 tugs
Damaged: 9 transports, 163 barges, 1 tug

Another 800-odd sorties were made against coastal targets, including such attacks as that made on the Dortmund-Ems Canal to slow the barge movement, reportedly closing the canal for some days. That total also includes attacks on coastal shipping movements - which was very unproductive (why they turned to the port bombing mid month) and Channel patrols that were part of the anti-invasion program, and, more interestingly, illumination missions for the Royal Navy night port bombardments.

Nor BTW, did Bomber Command operations in this period result in "quite a few losses". In fact, of the 3,141 totaol sorties for the month, just 65 aircraft were recorded missing and another 21 as 'crashed' for a 2.7 percent loss rate.

Oh, and what exactly were the "German reserve margins"? By 17 September the following had been collected at the ports:

155 transports (700,000 GRT) (another 13 were on the way)
1,277 barges and lighters (another 698 were being prepared or were on the way)
471 tugs (another 49 were on the way)
1,161 motorboats (another 439 were on the way)

So based on the numbers then in the ports the losses were 14 percent of the transport fleet, 17 percent of the barge fleet, and 1 percent of the tugs. Or you could say that after all those 'on the way' arrived the number available - assuming no further bombing losses would have been:

148 transports plus 9 damaged (164 required in the plan)
1,761 barges plus 163 damaged (1,653 required)
515 tugs plus 1 damaged (387 required)
1,600 motorboats (344 required - that seems a bit odd?)

[Andreas]

.... It would be bad economy - and totally out of the Dowding spirit - to use the fighters for this purpose......... ...

If we are about to abandon this topic for a bit I think this is an important point to reiterate. Even if the fleets AA performance in terms of shooting down attacking fighters is in questions. I agree that strafing the barges would be far from the best use for British fighters.

I'd use high level bombing. Even near or not so near misses would do the bizzo on a barge.

All the best

Andreas

In September '40 the Bomber Command performed attacks against the tight-packed invasion fleet in the Continental ports for 23 days. Different sources state the German losses to have been 8-12 % of the fleet (within the German reserve margins...). With quite a few losses to the RAF. So how could they do large damage on a spread-out landing force...?

I look forward to your posting the information verifying the convoy organisation of the Germans as spread-out.

All the best

Andreas

[John T]

I look forward to your posting the information verifying the convoy organisation of the Germans as spread-out.

All the best

Andreas

Andreas
Every source I have seen on the German build up in Channel ports stresses the congestestion that resulted.

Could you explain how, in any manner, a German convoy could navigate across the channel and still maintain the same target density as in port?

So to me there is no doubt that the convoy would spread out when leaving port.

Or do you have any sources stating that the vessels where dispersed in the channel ports?


Cheers
/John T

[Andreas]

The question is whether it spreads out to a degree that would make air attack less effective, which is what leandros is suggesting.

In the case of the ports, which were defended by stationary AA, you had many barges but in a small, defended target. So if the stick dropped even a bit off target, effect on the barges is zero. In the case of a convoy at sea, spreading it out a bit actually may make it more likely that you hit, considering that it is going to be less well defended. So it would have to be spread out sufficiently to overcome this effect.

I hope this is clearer now.

All the best

Andreas

[John T]

The question is whether it spreads out to a degree that would make air attack less effective, which is what leandros is suggesting.

Yes, and your question got a pretty obvious answer too.

In the case of the ports, which were defended by stationary AA, you had many barges but in a small, defended target. So if the stick dropped even a bit off target, effect on the barges is zero. In the case of a convoy at sea, spreading it out a bit actually may make it more likely that you hit, considering that it is going to be less well defended. So it would have to be spread out sufficiently to overcome this effect.

I hope this is clearer now.

All the best

Andreas

The lethal range of bombs is central in your reasoning so lets have a look at it.
If you want to maximize damage to unarmoured ships your choice would be a sligtly delayed fuze that lets the bomb to penetrate into the ship and then explodes and causes maximum blast damage, this is based on the assumption that you will hit.
If such a bomb misses it's target the lethal radius in water is a few meter, since it explodes a few metres down in the sea.

If you want to maximize the area that might be damage you'd like to use a very sensitive fuze that explodes the bomb at contact with the surface. On the other hand splinter have little chance to penetrate a steel hull, and a direct hit will do less structural damage to the ship, the superstructure will take most damage.
And the leathal radius of bomb shrapnel that has to penetrate a hull isn't very big, comparable with the effect on infantry in APC's. 15-30 meteres or so.

And since the ships will be spread out at least a couple of hundred meters, to navigate in convoys is obvious that Leandros are right.


Cheers
/John T.

[Andreas]

And since the ships will be spread out at least a couple of hundred meters, to navigate in convoys is obvious that Leandros are right.

I have serious doubts that the distance between e.g. tows and tugs is going to be on the order of 'a couple of hundred meters'. I also doubt that in an invasion attempt where one of the key elements is to have barges arrive on a constricted space as close to each other in time as possible the distance will be 'a couple of hundred metres' throughout the journey. In mid-channel, maybe (with the excemption of the tow-tug combos), but when getting near the beach, or during forming up outside the harbours, certainly not.

I therefore do not agree that 'leandros is obviously right'.

But even if we accept 'a couple of hundred metres', what would that do to the argument that a convoy could pour out concentrated fire at naval targets? Or do we now have magic convoys that on the one hand are spread out to avoid damage from aerial attack, but at the same time are close enough to concentrate the fire of their guns on attacking destroyers and MTBs?

All the best

Andreas

[LWD]

...
The lethal range of bombs is central in your reasoning so lets have a look at it.
If you want to maximize damage to unarmoured ships your choice would be a sligtly delayed fuze that lets the bomb to penetrate into the ship and then explodes and causes maximum blast damage, this is based on the assumption that you will hit.

Actually max damage is when the bomb penetrates through the ship and detonates under it. However if your target is barges detonating on contact will be plenty good enough. Indeed fragmentation bombs may be better than HE for direct hits.

If such a bomb misses it's target the lethal radius in water is a few meter, since it explodes a few metres down in the sea.

The shock wave may be capable of doing significant damage to the barge at more than a few meters.

On the other hand splinter have little chance to penetrate a steel hull, and a direct hit will do less structural damage to the ship, the superstructure will take most damage.

The steel hulls are hardly armored hulls. I strongly suspect that splinters would have little trouble penetrating a barges hull.

And the leathal radius of bomb shrapnel that has to penetrate a hull isn't very big, comparable with the effect on infantry in APC's. 15-30 meteres or so.

APC's have armored "hulls" that's what the "A" stands for. The hull on the barges is likely to be both thinner and softer.

[John T]

And since the ships will be spread out at least a couple of hundred meters, to navigate in convoys is obvious that Leandros are right.

I have serious doubts that the distance between e.g. tows and tugs is going to be on the order of 'a couple of hundred meters'.

I can agree that the tug and its barges would be closer but each such combo would need some leeway to the next or you'd risk a terrible mid-channel spagetti-carbonara!

I also doubt that in an invasion attempt where one of the key elements is to have barges arrive on a constricted space as close to each other in time as possible the distance will be 'a couple of hundred metres' throughout the journey.
In mid-channel, maybe (with the excemption of the tow-tug combos), but when getting near the beach, or during forming up outside the harbours, certainly not.

Would you elaborate on this?
I got the impression, that the assult should be spread out over a number of beaches. Much more dispersed than during D-Day.
So concentration in time was more important than concentration i space.

It is while forming up that you'd really need the space to manouver.

You easily accept the fact that these barges where hard to navigate cross the channel, since it supports you view that seelöve where impractical but you seems unwilling to accept the consequence to those who should try to navigate these barges and to those who should bomb them.

I therefore do not agree that 'leandros is obviously right'.

As a personal observation, I doubt you will agree with Leandros on anything regarding Seelöve

But even if we accept 'a couple of hundred metres', what would that do to the argument that a convoy could pour out concentrated fire at naval targets? Or do we now have magic convoys that on the one hand are spread out to avoid damage from aerial attack, but at the same time are close enough to concentrate the fire of their guns on attacking destroyers and MTBs?

All the best

Andreas

If you would please try to look at the physical reality rather than trying to score point with rethorics you might see it.

A bomb exploding in water damage a ship in a radius of a few meters.
A convoy is dispersed as a target from bombing attack if the ships are a few hundred of meters from each other.
Gunnery range is measured in the range 4 000 to 12 000 meters.

What about to use checked paper and then draw the three circles in the same scale?

Cheers
/John T.

[John T]

...
The lethal range of bombs is central in your reasoning so lets have a look at it.
If you want to maximize damage to unarmoured ships your choice would be a sligtly delayed fuze that lets the bomb to penetrate into the ship and then explodes and causes maximum blast damage, this is based on the assumption that you will hit.

Actually max damage is when the bomb penetrates through the ship and detonates under it. However if your target is barges detonating on contact will be plenty good enough. Indeed fragmentation bombs may be better than HE for direct hits.

Any Source that consider RAF bombs at that time and the intended targets?
That is 250 - 500 Lbs bombs against barges?
It should work with the 2000 Lbs bomb but they where few.

That modern ships does break the keel when attacked by modern torpedoes or bombs with much larger warheads isn't the same as small bombs against sturdy built ships.

Actually the size of British Fragmentation bombs where 20Lbs...

If such a bomb misses it's target the lethal radius in water is a few meter, since it explodes a few metres down in the sea.

The shock wave may be capable of doing significant damage to the barge at more than a few meters.

Any Source that consider RAF bombs at that time and the intended targets?

On the other hand splinter have little chance to penetrate a steel hull, and a direct hit will do less structural damage to the ship, the superstructure will take most damage.

The steel hulls are hardly armored hulls. I strongly suspect that splinters would have little trouble penetrating a barges hull.

My source say's comercial steel is aprox 30% less effective than modern armoured steel against splinters. Splinter penetration is based on the weight of the single splinter and it's speed. RAF Bombs in 1940 where hardly optimized for either.

And the leathal radius of bomb shrapnel that has to penetrate a hull isn't very big, comparable with the effect on infantry in APC's. 15-30 meteres or so.

APC's have armored "hulls" that's what the "A" stands for. The hull on the barges is likely to be both thinner and softer.

Yes it is thinner and softer but still thick enough to stop most splinters, since splinters isn't made to penetrate structures. Today with prefragmentated warheads you have another situation.


Cheers
/John T

[RichTO90]

I can agree that the tug and its barges would be closer but each such combo would need some leeway to the next or you'd risk a terrible mid-channel spagetti-carbonara!

Well, that gets interesting. The actual German description for the tows in the Schleppezüge was in groups of three "nebeneinander" or literally "next to each other". I also thought by that they meant towing in line ahead, but in German I think that would be something like "ein nach dem anderen" or something?

No if they are literally "side by side" then of course that makes them more stable and simplifies the problem of beaching them, but it also makes for a larger target. And it also makes it much harder to tow them given the additional bow resistance. But if they were towed line ahead then how were they to get them to the beach side by side? And they would of neccessity not be able to do close tows as in a river or canal, since the swells alone would cause that to be problematic, but the problem of control increases as the distance between the tows increases, the tug would have literally no control over the last barge in the troika.

See the problems that the Heer conveniently chose not to worry about?

Would you elaborate on this?
I got the impression, that the assult should be spread out over a number of beaches. Much more dispersed than during D-Day.
So concentration in time was more important than concentration i space.

It is while forming up that you'd really need the space to manouver.

The first wave schematically was (note the number of MS, RB, and VP is approximate):

Heeresgruppe A
Generalfeldmarschall Gerd von Rundstedt
16.Armee — Generaloberst Ernst Busch
First Wave
XIII.Armee-Korps (Folkestone-Dungeness/New Romney) General Heinrich-Gottfried von Vietinghoff genannt Scheel
Transportflotte B
Schleppverband 1 (Dunkirk)
Minensuchflottille 3 (8 minesweepers, M15-19, 22, 29, and 30)
Räumbootsflottille 11 (8)
Vorpostenflottille 3 (8 V301-308)
Schleppzüge: 75 (each towing three barges)
Geleitzug 1 (Ostende)
Minensuchflottille 16 (9 minesweepers, M1601-1609)
Dampfer: 8 (planned 15)
Prähme: 16 (planned 30)
Motorboote: 16 (planned 30)
Schleppverband 2 (Ostende)
Räumbootsflottille 3 (8 R33-R40)
Vorpostenflottille 2 (8 V201-208)
Schleppzüge: 24 (each towing three barges)
Geleitzug 2 (Rotterdam)
Minensuchflottille 4 (still organizing and only three operational, M1, 2, and 36)
Dampfer: 49
Prähme: 98
4./Bau-Lehr-Regiment z.b.V. 800 Brandenburg (direct assault on Dover)
17.Infanterie-Division
Kp./Bau-Lehr-Regiment z.b.V. 800 Brandenburg
Tauchpanzer-Abteilung ‘B’
35.Infanterie-Division
1./Bau-Lehr-Regiment z.b.V. 800 Brandenburg (131 men with m/c)
Tauchpanzer-Abteilung ‘D’ (minus one company)
II./Luftwaffe-Flak-Regiment 14
VII.Armee-Korps (Rye-Hastings) Generaloberst Eugen Ritter von Schobert
Transportflotte C
Schleppverband 3 (Calais)
Minensuchflottille 1 (5 minesweepers, M3, 4, 6-8)
Minensuchflottille 32 (28 converted fishing boats, M3200-3227)
Räumbootsflottille 4 (12 R41-R52)
Vorpostenflottille 7 (8 V701-708)
Schleppzüge: 99 (each towing three barges)
Geleitzug 3 (Antwerpen)
Minensuchflottille 15 (8 converted trawlers, M1501-1508)
Dampfer: 57 (planned 50)
Prähme: 114 (planned 100)
Motorboote: 14 (as planned)
Tauchpanzer-Abteilung ‘A’
1.Gebirgs-Division
7.Infanterie-Division
I./Luftwaffe-Flak-Regiment 26
I./Bau-Lehr-Regiment z.b.V. 800 Brandenburg (-) (presumed)
9.Armee — Generaloberst Adolf Strauss
First Wave
XXVIII.Armee-Korps (Bexhill-Eastbourne/Beachy Head) General Erich von Manstein
Transportflotte D
Schleppverband 4 (Boulogne)
Minensuchflottille 2 (4 minesweepers, M9, 10, 12, and 13)
Minensuchflottille 18 (8 converted trawlers, M1801-1808)
Räumbootsflottille 2 (9 R25-R32)
Vorpostenflottille 15 (8 V1501-1508)
Vorpostengruppe 16 (3 Schiff 9, 18, and 37)
Vorpostengruppe 18 (3 Schiff 7, 27, and 27)
Schleppzüge: 164 (each towing four barges)
Tauchpanzer-Abteilung ‘C’
26.Infanterie-Division
11./Bau-Lehr-Regiment z.b.V. 800 Brandenburg (two teams with 110 men on m/c, assigned to destroy the battery and radio station at Beachy Head)
34.Infanterie-Division
11./Bau-Lehr-Regiment z.b.V. 800 Brandenburg (one team of 48 men on m/c)
I./Luftwaffe-Flak-Regiment 3
VIII.Armee-Korps (Beachy Head/Selsey Bill-Brighton) General Walter Heitz
Transportflotte E
Schleppverbandverband 5 (Le Havre)
Räumbootsflottille 1 (8 R17-R24)
Vorpostenflottille 4 (8 V401-408)
Vorpostenflottille 13 (13 V1301-1308)
Vorpostenflottille 20 (8 V2001-2008)
Motorboot: 200
Motorsegler: 100
Schlepper: 25 (each towing three barges)
Geleitzug 4 (Le Havre)
Minensuchflottille 12 (5 converted trawlers, M601-605)
Dampfer: 25 (as planned)
Prähme: 50 (as planned)
Geleitzug 5 (Le Havre)
Minensuchflottille 14 (8 converted trawlers, M1401-1408)
Dampfer: 25 (as planned)
Prhme: 50 (as planned)
Kp./Tauchpanzer-Abteilung ‘D’
6.Gebirgs-Division
8.Infanterie-Division
28.Infanterie-Division
I./Luftwaffe-Flak-Regiment 36
X. Armee-Korps – General der Artillerie Christian Hansen
I./Luftwaffe-Flak-Regiment 29

You easily accept the fact that these barges where hard to navigate cross the channel, since it supports you view that seelöve where impractical but you seems unwilling to accept the consequence to those who should try to navigate these barges and to those who should bomb them.

Er, unpowered barges don't "navigate" they get towed. And of course it was problematical, the barges were designed for towing on canals, rivers, and coastal waters, not the open sea and not with a cargo of people and animals.

If you would please try to look at the physical reality rather than trying to score point with rethorics you might see it.

A bomb exploding in water damage a ship in a radius of a few meters.
A convoy is dispersed as a target from bombing attack if the ships are a few hundred of meters from each other.

But they cannot be, since about three-quarters of the vessels are in tow, with minimal maneuverability. The towing vessel itself could be a hundred yards away from the closest barge, but they cannot be hundereds of yards from each other too, it simply becomes impossible to navigate at then.

And who is watching out for the hundreds of yards of towline in all this? And how easily can a towline be severed by a bomb fragment?

Gotta go, beer beckons. Or maybe ine. Later.

[Andreas]

And since the ships will be spread out at least a couple of hundred meters, to navigate in convoys is obvious that Leandros are right.

I have serious doubts that the distance between e.g. tows and tugs is going to be on the order of 'a couple of hundred meters'.

I can agree that the tug and its barges would be closer but each such combo would need some leeway to the next or you'd risk a terrible mid-channel spagetti-carbonara!

I fully agree - the question is how much leeway are we talking about? That's why I would like to see a planning diagram of how the Germans expected a divisional convoy to look like.

I also doubt that in an invasion attempt where one of the key elements is to have barges arrive on a constricted space as close to each other in time as possible the distance will be 'a couple of hundred metres' throughout the journey.
In mid-channel, maybe (with the excemption of the tow-tug combos), but when getting near the beach, or during forming up outside the harbours, certainly not.

Would you elaborate on this?
I got the impression, that the assult should be spread out over a number of beaches. Much more dispersed than during D-Day.
So concentration in time was more important than concentration i space.

If you bring a divisional assault onto a beach, you are looking at two regimental groups with 1,250 men + support each for the initial landing, IIRC. That would give you somewhere between 30-60 barges I'd say, depending on their size. All of these should really arrive at the beach closely in time, and closely in space.

It is while forming up that you'd really need the space to manouver.

You easily accept the fact that these barges where hard to navigate cross the channel, since it supports you view that seelöve where impractical but you seems unwilling to accept the consequence to those who should try to navigate these barges and to those who should bomb them.

I have no doubt that the Germans, given good weather conditions and absence of opposition, i.e. in an ideal theoretical situation, would have been able to get the vast number of their barges across. I do not think that seaworthyness of the barges would have been the key issue to the success of Seelöwe.

I therefore do not agree that 'leandros is obviously right'.

As a personal observation, I doubt you will agree with Leandros on anything regarding Seelöve

That's because he has a habit of selectively getting his quotations from Schenk wrong in such a way that they seem to support his view.

But even if we accept 'a couple of hundred metres', what would that do to the argument that a convoy could pour out concentrated fire at naval targets? Or do we now have magic convoys that on the one hand are spread out to avoid damage from aerial attack, but at the same time are close enough to concentrate the fire of their guns on attacking destroyers and MTBs?

All the best

Andreas

If you would please try to look at the physical reality rather than trying to score point with rethorics you might see it.

A bomb exploding in water damage a ship in a radius of a few meters.
A convoy is dispersed as a target from bombing attack if the ships are a few hundred of meters from each other.
Gunnery range is measured in the range 4 000 to 12 000 meters.

What about to use checked paper and then draw the three circles in the same scale?

Cheers
/John T.

As I said before - I am perfectly happy to accept the dispersion argument for part of the journey. I think there would have been a window of opportunity for Bomber Command to interfere during the forming up for and the actual run-in, not before. In that case they would have been presented with a good target, but it would have been an opportunity restricted in time and space. I am not aware of BC plans to actually do that. In actual fact the time of BC may have been better spent attacking the departure harbours to interfere with the preparations for the second wave.

All the best

Andreas

[LWD]

....
Actually max damage is when the bomb penetrates through the ship and detonates under it. However if your target is barges detonating on contact will be plenty good enough. Indeed fragmentation bombs may be better than HE for direct hits.

Any Source that consider RAF bombs at that time and the intended targets?

I was talking theoretically as I thought you were. Most pure HE bombs will break up if there is much of a delay on them. So you go for a surface burst. Against barges this is probably more than adequate for the bombs such as you discuss below.

That is 250 - 500 Lbs bombs against barges?
It should work with the 2000 Lbs bomb but they where few.

I remember reading that a number of ships (DDs) in the Pacific were badly damaged by near misses with 500 and 1000 lb bombs. I don't think anyone did this intentionally in WWII with bombs. I believe it was one of the reasons they tried to get the magnetic detonators to work for torpedoes however.

That modern ships does break the keel when attacked by modern torpedoes or bombs with much larger warheads isn't the same as small bombs against sturdy built ships.

I agree but, I wouldn't consider the barges to be sturdy in so far as their ability to take damage from bombs and bullets. Not sure you could actually hit one with a torpedo becuase their draft is so shallow.

Actually the size of British Fragmentation bombs where 20Lbs...

I suspect that a couple would enough to put a few holes in the hull and or cause enough other damage that the barge or at least it's cargo would be significantly degraded.

If such a bomb misses it's target the lethal radius in water is a few meter, since it explodes a few metres down in the sea.

The shock wave may be capable of doing significant damage to the barge at more than a few meters.

Any Source that consider RAF bombs at that time and the intended targets?

Again look at the damage reports on ships in the Pacific. Proably also available for those in the Atlantic. (we could be operating under different definitions of a few meters though).

My source say's comercial steel is aprox 30% less effective than modern armoured steel against splinters. Splinter penetration is based on the weight of the single splinter and it's speed. RAF Bombs in 1940 where hardly optimized for either.

Any idea how thick the hull of the barges was? Were they all steel hulled or were some wooden?

And the leathal radius of bomb shrapnel that has to penetrate a hull isn't very big, comparable with the effect on infantry in APC's. 15-30 meteres or so.

APC's have armored "hulls" that's what the "A" stands for. The hull on the barges is likely to be both thinner and softer.

Yes it is thinner and softer but still thick enough to stop most splinters, since splinters isn't made to penetrate structures. Today with prefragmentated warheads you have another situation.

Part of the problem in WWII was even when they designed things to fragment they didn't necessarily do it the way they planned. I've read that for instance the US pineapple style hand grenade tended to brake into a bunch of very small and several large fragments. The lethal range of the large fragments was greater than the distance you were suppose to be able to throw it. Indeed most of the fragments/splinters would miss and many others would be stopped. However the ones that would penetrate would be the larger more damaging ones. Now if it detonates a few meters under water the water will probably stop most or even all the fragments unless it is very close. I frankly don't know how far a British HE bomb would travel before it detonated if it had an "instantaneous" fuse. Anyone else got any info on that?