No announcement yet.

A decisive Battle of the Caribbean

  • Filter
  • Time
  • Show
Clear All
new posts

  • A decisive Battle of the Caribbean

    Bear with me, it's going to take a while and several posts to get this all out

    On the 11th of December 1941, Hitler declared war on the USA. Before this, the German navy’s (the Kreigsmarine, hereafter the KM) U-boat force commanded by Admiral Doenitz had been hamstrung with rules of engagement (ROE) that attempted (although not always successfully) to prevent any incidents between German forces and the USA. Now the ‘gloves were off’.

    Doenitz instituted Operation Paukenschlag (Drumbeat) which consisted of 5 U-boats given ROE that allowed them to attack any shipping formally considered to be in the US sphere of influence.

    The effects of the initial Drumbeat boats and follow on waves of U-boats to shipping on the US east and gulf coasts and in the Caribbean was dramatic. In the first 6 months of 1942, 397 ships totaling over 2 million tons of shipping went down. The Germans lost just 7 U-boats in arguably the single greatest defeat in the history of the USN.

    A bit more extensive summary here:

    But beyond its’ tactical success can the entire Drumbeat, follow on waves, and the Battle of the Caribbean be classified as more than a tactical success for the Germans? It was not until July of 1943 that Allied shipbuilding replaced ships faster than they were being replaced. Yet throughout the battles of 1942, the trickle of supplies continued across the Atlantic to fuel Britain’s resistance.

    But Allied success through 1942 was a closer thing than it may appear. Stocks of fuel held at Halifax, Canada and St.John's, Newfoundland were just 45,000 tons by the end of April. This was only fifteen days supply for the escorts of critical transatlantic convoys.
    ( )

    In effect, Britain was 15 days away from being unable to fuel the escorts of her convoys!

    Could Doenitz have done anything to change his fortunes in this battle?
    Amateurs study tactics, Professionals study logistics.

  • #2
    The proposal

    The Drumbeat wave consisted of only 5 boats because only the type IX had the range to get to the US coast and have fuel left for a reasonable amount of time on station (typically two weeks). Only 12 of these were available, of those higher command had already earmarked 6 for operations off Gibraltar, leaving Doenitz with 6 boats. One was unfit for sea and headed into a maintenance period, meaning the Drumbeat wave would be just 5 boats.

    I believe that part of the problem was Doenitz’ fascination with the U-boat “quotient”. This was simply the average sinking per U-boat per day, considering all U-boats at sea. Related to this was his ‘tonnage war’, he is quoted as saying “The shipping of the enemy powers is one great whole. It is therefore in this connection immaterial where a ship is sunk—it must still in the final analysis be replaced by a new ship”

    While true in broad strokes, it does not account for the true threat axis of his opponents. For example sinking 10 tons of fruit bound for Canada is less important than sinking 5 tons of grain bound for the UK, and far less important than sinking 1 ton of oil bound just about anywhere it can be used to fuel Germany’s enemies.

    And oil is the blood of the Allied war effort that Doenitz came close to drying up even without putting forth his best effort to do so.

    The KM must strike hard at the most valuable and vulnerable targets and keep the pressure on. This was the oil reserves flowing through the Caribbean and along the gulf coast of the USA. At the time the battle started, 95% of American oil passed from gulf ports bound for refineries on the US east coast. Up to 80% of British oil imports originated in Venezuela.

    In February 1942, 25 tankers were sunk in the Caribbean. What else could Doenitz have done? He needed either to increase the number of U-boats on station or increase the time on station of the boats he had.

    He had the possibility of doing both.
    Amateurs study tactics, Professionals study logistics.


    • #3
      Keeping the U-boats on station longer

      Throughout this “what if” I will attempt to utilize only the assets that Doenitz and the Kriegsmarine really had available for operations in this theatre. Higher commands’ penchant for sending u-boats into the Mediterranean or off the coast of Norway will be assumed to have continued.

      One answer to keeping U-boats on station longer was the development of the Type XIV “Milk Cow” U-boat. These were boats designed to provide fuel, food, potable water and weapons to the ‘fighting’ u-boats in order to extend their time on station. They were hugely successful and the targets of a concerted effort by the allies to destroy them utilizing every available resource including Ultra intercepts.

      However, the first of these boats, U-459, did not become operational until March of 1942 and was not on station to supply U-boats until well into April ( ). Follow on boats were later still.

      What Doenitz did have on hand that could have done the job were:
      1. The auxiliary cruiser THOR (available in La Rochelle France until 17 Dec, broke into the Atlantic 17 Jan, crossed the equator 4 Feb 42. )
      2. The auxiliary cruiser MICHEL (Broke into the Atlantic 20 March, reached the equator 5 April);
      3. The auxiliary cruiser STIER (broke into the Atlantic 20 May from Royan France, the last surface raider to successfully break out)

      (Information on all here: )

      4. The oil tanker CHARLOTTE SCHLIEMANN (stranded in Las Palmas, Canary Islands since the beginning of the war.,58737,58741 )
      5. The Schiff 53 DOGGERBANK (Broke into the Atlantic in mid-Jan 42 with 280 mines embarked )
      6. A host of “bits and pieces” including weather ships and trawlers whose utility was limited, but perhaps creative minds on these forums will see something I don’t ( )

      The quick proposal, the 5 initial Drumbeat boats will sail and start the war off the US east coast. Historically they ended their operation on the 6th of Feb and headed for home. Instead I would order them south to meet the THOR, DOGGERBANK and the CHARLOTTE SCHLIEMANN who have sailed in support of the U-boat campaign, not the ‘dashing’ but ultimately far less successful raider campaign in distant waters.

      How they provide that support still to come.
      Last edited by Roadkiller; 16 Apr 09, 21:57.
      Amateurs study tactics, Professionals study logistics.


      • #4
        Replenishment at sea for U Boats

        Good Thread.

        Would surface units survive long enough to make an effective, long term difference to the Drumbeat campaign? I'm inclined to doubt it as the various navy's would become aware of their activities and make it a priority to hunt them down in just the same way the Milch Cows were.

        The long and the short of it is that the KM just didn't have the numbers available to them at the time, especially as you pointed out, so many other boats were being diverted elsewhere eg the Mediterranean.

        Perhaps if Italian submarines could have been used in conjunction with the KM's then this could have helped matters but they weren't really suited to Atlantic operations even though several were (I believe) sent there.

        Numbers were the key here and they didn't have them. Just think what they would have been able to achieve with just a dozen more operational IX's in the theatre. Think also what might have been possible had the Walther propulsion system been pursued with more vigour. The figures you quote for fuel oil available to the escorts is startling to say the least.

        "Believe me, nothing except a battle lost can be half so melancholy as a battle won." - Duke of Wellington at Waterloo.


        • #5
          The second artical posted above approches the core of the problem & the reason for so many ships sunk in early 1942. The USN had refused to learn from British experince, and made the same mistake of thinking that convoys were unecessary. While the British had control over any ships leaving the East Coast ports of North America for the UK or Mediterranian the USN had control over the inter coastal routes and the Carribean. Convoys were not organized on those routes. Adm King came close to losing his position over this decision. Roosevelt had acess to the same numbers for ships sunk, cargo lost, and fuel available; actually better numbers than in the artical; and Adm King was warned. King was stubborn, disliked the British, disrespected about anything outside the USN, but he was not stupid. Convoys were formed in US waters and the methods for defending against German subs changed.

          Here is a comparison of cargo losses in the Atlantic for cargo destined for ports in the UK. It does not reflect all cargo lost in the Carribean or Western Atlantic as only part of that was destined for the UK.

          Quantities are estimates of cargo not ship displacement.

          Cargo...docked in UK.......Sunk.......Sunk by Sub...% Total........%Sub
          1941.....25,496,000....1,979 ,000...1.390,00......7.8 (5.5)......5.5 (3.9)
          1942.....24,480,000....3,694 ,000...3,408,00....15.8 (10.6)...13.5 (9.7)
          1943.....30,601,000....1,321 ,000...1.159,00......4.3 (3.0)......3.8 (2.7)

          In 1942 slightly over 2.1 millions tons displacement of ships were sunk in the first six months in the US Carribean & East Coast zones.

          Numbers are drawn from records of the Board of Trade 'Shipping Movement at UK Ports', Morison 'History of USN Operations in WWII', Jacobsen & Rohwer 'Decisive Battles of WWII: The German View' - 'The U-boat War Against the Allied Supply Lines'. These are presented by Ellis in 'Brute Force'

          Here is a comparison of Allied ships built vs sunk. It clearly shows the problem of sunk vs replacement existed long before 1942. Numbers are in tons displacement. The numbers in the first two columns I had to round off as they were presented in a bar graph. The last column is not a direct representation of the net of the first three as it included ships lost to storms, scrapped, LL to the USSR, and those added from sources other than the builders.

          ...........Built UK...........built US...........Sunk........Combined Cargo Fleet
          1940.....78,000................NA............4,005 ,000........33,794,000
          1941...1,200,000...........800,000........4,355,00 0........32,988,000
          1942...1,900,000........5,950,000........7,788,000 ........32,076,000
          1943...2,500,000.......13,500,000........3,220,000 ....... 35,571,000

          From Ellis again, drawing from the US Statistical Abstract & 'History of the Second World War, UK Civil Series'.

          German Submarines lost in the Atlantic for this period are:
          Jul-Sept 1941......6

          Oct-Dec 1941.....17

          Jan-Mar 1942.....11

          Apr-Jun 1942.....10 East Coast convoys established

          Jul-Sept 1942.....31 East Coast convoys active, subs patrols to Carribean

          Oct-Dec 1942.....34 Carribean convoys active, sub patrols return to UK Western Approaches.

          One final statistic. The overall average tonnage (displacement) sunk per sub rises from 10,000 tons in January 1942, to 30,000 per sub in June 1942. It then falls off to 12,000 per by Dec 1942. For those operating in the USN zone of the East Coast and Carribean the average per sub rockets up to a incredible 90,000 tons in the late spring. It then collapses back to under 20,000 tons average as the summer passes.

          While there are several reasons for the Allied losses in the USN zone the lack of convoys is commonly accepted as the core cause. Post war remarks by German submarine leaders focus on this "mistake". The British remarks on this during the war border on the frantic, as they tried to convince the USN of its error.

          While it is tough to predict these things, I suspect that a more intensive submarine attack in US waters in early 1942 would result in a faster adoption of the convoy system. Roosevelt had endorsed the 'retirement' of a large number of US Generals and Admirals in 1940, 41, & 42. Had the losses of ships inceased even faster I have no doubt Roosevelt would have replaced King.


          • #6
            Originally posted by Dogsbody67 View Post
            Good Thread.

            Would surface units survive long enough to make an effective, long term difference to the Drumbeat campaign? I'm inclined to doubt it as the various navy's would become aware of their activities and make it a priority to hunt them down in just the same way the Milch Cows were.
            The first set of numbers in my post shows that surface ships & aircraft accounted for barely 10% of cargo lost. The Scharnhorst/Genisenau surfce raid sank 115,000 tons displacement. Tho many of the ships sunk were in a empty convoy deadheading back to North America.

            Originally posted by Dogsbody67 View Post
            The long and the short of it is that the KM just didn't have the numbers available to them at the time, especially as you pointed out, so many other boats were being diverted elsewhere eg the Mediterranean..
            Probablly all those in the Med were the shorter range types, unsuitable for Western Atlantic patrols. Maybe those should have been concentrated around the UK? Tho it takes months to relocate these squadrons.

            Originally posted by Dogsbody67 View Post
            Perhaps if Italian submarines could have been used in conjunction with the KM's then this could have helped matters but they weren't really suited to Atlantic operations even though several were (I believe) sent there.
            Some were. All long range types. I think they had the advantage of not using Donetz's communications doctrine. So, they were difficult to locate by radio intercept.


            • #7
              Using the THOR in support of the U-boats:

              Thanks for the great replys! More information for me to ponder in putting together my thesis that Doenitz did not follow the principal of concentration fo force and he could have done so with more thought to the three "R's". Refuel, Rearm, Rest.

              Here is what I see for the THOR, there is more speculation in it than I would like but if there is hard data out there, I'd appreciate the input.

              The THOR was small for a raider at just over 3800 tons and 122 meters in length. This was apparently about the size of a channel steamer of the time. But armed with six 5.9-inch guns, one 60-millimetre to simulate the small gun carried at the stern of all Allied defensively equipped merchant ships, two 37-millimetre and four 20-millimetre light anti-aircraft guns, four torpedo tubes and an Arado Ar 196 float plane and radar, she was very capable.


              She is in La Rochelle when war on the USA is declared. There is not much time to modify the ship, but we can change her mission from surface raiding to supporting the coming U-boat offensive. Her main task will be to provide the boats with torpedoes and stores, secondarily to provide scouting and finally provide protection to the CHARLOTTE SCHLIEMANN (more on her later).

              I cannot find with the resources I currently have on hand how many actual torpedoes she carried (anyone?). I have counted the number of torpedoes reported to have been fired during her cruises and it is apparent she had reloads on board. She was also capable of transferring torpedoes at sea because she did replenish. ( )

              German supply ships were capable of carrying torpedoes in crates as deck cargo. In the case of THOR I will do so and to save space put the warheads in one of the 5.9 inch magazines.

              A slightly smaller ship, the Alstertor, carried 10 complete torpedoes as cargo, along with 1500 15cm shells and a host of other supplies including two float planes in crates. ( )

              I’m going to give the THOR 30 torpedoes (I'd love to say she could carry more but I'm not comfortable doing so) and send her to the eastern edge of the Caribbean arriving in early February. There she will meet the 5 Drumbeat boats and the CHARLOTTE SCHLIEMANN. She will give each boat 6 torpedoes and stores.

              Orders to the boats "You have at least six torpedoes and a deck gun, make them count". They go into the Caribbean. This is months before they returned to action historically. The U-125 for example went off station in early Feb and did not even depart for her next cruise until 4th of April ( ).
              Amateurs study tactics, Professionals study logistics.


              • #8
                I considered Italian submarines and may return to the idea. However, they slow diving and suffered from Command and Control problems making the difficult to integrate into a wolf pack.

                The biggest issue was that shore authorities laid out the patrol route before the boat departed. The boat's CO was not allowed to vary from that. Which was quite inflexible considering the nature of submarine warfare.
                Amateurs study tactics, Professionals study logistics.


                • #9
                  Using the CHARLOTTE SCHLIEMANN in support of the U-boats:

                  Trying not to overwhelm everyone with too much information but getting all those boats and ships to sea and into the operations area is a logistical nightmare

                  Our fuel source:

                  The CHARLOTTE SCHLIEMANN was reported to be carrying 10 800 tons of oil fuel during her time in the Canary Islands. When she sailed historically on the 24th of Feb 42 her mission was to fuel the diesel powered raiders MICHEL and STIER. She refueled each at least 3 times. She also refueled at least 7 different U-boats off Madagascar during that deployment.

                  In this “what if” her mission is simple; she is to sail from Las Palmas and take up station in the eastern Caribbean in mid-Jan and prepare to fuel U-boats. This will include the original Drumbeat boats mentioned above and follow on groups to be discussed later. Therefore she will be required to slip approximately 7 weeks earlier than historical to allow a two week transit from the Canaries to be in her operations area on time. So be it, this shouldn’t be a critical stop point for the ‘what if’

                  THOR will rendezvous with her early February.


                  Anyone still out there, thank you for your patience
                  Amateurs study tactics, Professionals study logistics.


                  • #10
                    Info 1: Fueling U-boats at sea:

                    "In order to receive fuel, the U-Boat takes station astern of the tanker, whose motor boat assists in passing a hawser and the oil fuel hose. The hawser is then secured to the bows of the U-Boat. To prevent the hose sinking on the way over to the U-Boat, it is filled with air and the end to be fitted to the U-Boat is closed. The hose is then connected and the oil is pumped through. During the process, should the U-Boat come too close to the tanker, she is easily kept away by a few revolutions of her diesels. On an average the actual fueling was said to have taken approximately two hours. "

                    Amateurs study tactics, Professionals study logistics.


                    • #11
                      Info 2: Transferring torpedoes at sea:

                      "Torpedoes were transshipped by fixing practice heads and towing them with a motor boat. … Torpedoes are transported to the U-Boat in rubber floats said to be about 20 ft. long, which are towed by the motor boat. One torpedo only can be carried at time in the float which is manned by two ratings from the tanker. The torpedoes are hoisted by a davit in the U-Boat situated close to the forward torpedo-hatch."

                      Amateurs study tactics, Professionals study logistics.


                      • #12
                        Increasing the number of U-boats on station:

                        I will continue to flog the horse here folks, but I'm almost there:

                        The Type VII U-boat did not have the fuel capacity to reach the Caribbean, have a useful patrol length and return home. Eventually, by putting fuel oil in one of their water tanks, they had the legs to make the journey. Of course the reduction in potable water reduced their time on station. The introduction of the “Milk Cow” solved that problem. But one is not available for a couple of months.

                        However, we have a support group that can fuel a VII before it enters the operational area. How many VII’s could Doenitz have sent immediately if he had had this capability?

                        If you follow the link you will find a tool that will enable you to find which U-boats were on patrol during given periods. Enter 1942, Jan, 01. This will provide a list of submarines that sailed historically in the time frame required:

                        Of these I would only consider those sailing from Lorient, St Nazaire, and Brest to be available for our tasking, 15 boats. 5 of those are the original Drumbeat boats. U-43 left Lorient and did a patrol off Norway, so I’ll consider her untouchable. That leaves 9 boats that historically were uninvolved in the initial wave that we will now employ in our operation.

                        We sail them as they did historically, but they proceed to the Caribbean under the same “do not engage” orders as the Drumbeat boats. They meet the CHARLOTTE SCHLIEMANN, refuel and carry on into the operation area. They will start the Battle of the Caribbean in a big way. I expect the first boat would be refueled and start its’ patrol in the Caribbean in late January, with the rest taking up station every few days thereafter.

                        On completion of their first patrol (2 – 3 weeks) they will not return to France, they will rendezvous with the supply group to resupply with fuel, stores and torpedoes (from the DOGGERBANK see below) and return to the fray for their second patrol in the operations area.

                        After their second patrol, they, like the original Drumbeat boats, will be refueled and return to France.
                        Amateurs study tactics, Professionals study logistics.


                        • #13
                          The DOGGERBANK:

                          The last piece of the puzzle:

                          The DOGGERBANK was a captured British ship originally named the Speybank. She was converted to an auxiliary minesweeper and U-boat support ship. She was armed with 1 x 102 mm cannon, 2 x 20 mm guns, 155 type EMC mines, 55 type EMF mines, and 70 type TMB mines. She could also carry 50 torpedoes to rearm U-boats.

                          Historically she broke into the Atlantic in mid January and headed for the coast of South Africa. The only thing we’ll change is her destination (eastern Caribbean) and her mission. Her primary mission will be to supply U-boats with torpedoes, stores and potable water. She should be on station to provide that after the first week of February, which allows her to make the transit in 3 weeks, although she may be quicker.

                          I expect that she’ll expend her torpedo load sending the wave of Type VII boats that arrived on station starting in mid January back into the operations area in early/mid February for their second patrol.

                          DOGGERBANK will then be free to pursue her secondary mission, mining the approaches to Curacao and Aruba, home to some of the largest refineries available to the Allies.

                          I will try to summarize all of the previous into something a bit more digestable soon. For anyone whose waded through all this for me, I appreciate your forebearance
                          Amateurs study tactics, Professionals study logistics.


                          • #14
                            Originally posted by Roadkiller View Post
                            I considered Italian submarines and may return to the idea. However, they slow diving and suffered from Command and Control problems making the difficult to integrate into a wolf pack.
                            This had some advantage. The ridiculously frequent radio transmissions required by the German command/control methods gave the British signals intel people too much usefull information. Even while the Enigma submarine encryption keys were not knowd direction finding alone was a godsend for the British. Other forms of signal analysis were usefull as well.

                            Originally posted by Roadkiller View Post
                            The biggest issue was that shore authorities laid out the patrol route before the boat departed. The boat's CO was not allowed to vary from that. Which was quite inflexible considering the nature of submarine warfare.
                            This tied in to the German submarine commands efforts to control the patrols of the subs. They were frequently sent orders concerning the adjustment of their patrol routes and stations. This was acceptable while the Britis were locked out of the encryption keys. But, when they were able to read the messages they learned exactly where the sub addressed was to head for.


                            • #15
                              Italian subs and other bits -

                              Good points Carl. However I do not think that creating a rigid patrol line and not allowing the submarine to deviate from it is a better answer.

                              The KM really should have been more concerned about HF/DF capabilities as they had similar technologies themselves. This strikes me as blind optimism on their part.

                              Enigma was a tool used by the KM and they had to believe the experts who said it was unbreakable. I don't hold the KM responsible for not anticipating Ultra. It's worth noting in the context of this thread that Doenitz ordered an extra wheel added to the Enigma machines and Ultra intelligence regarding the U-boat war dried up starting in Feb 1942 for the balance of the year.

                              I would suggest that the KM should simply have broadcast from ashore their latest intelligence (covered of course). U-boats would copy the broadcast and rely on the Commanding Officer's own initiative and knowledge of his own situation on which targets to make a try for. No reply required, limiting HF/DF possibilities.

                              Although the formation of wolfpacks might have been more slapdash, I believe the overall effect would have been about the same. Likely with fewer losses.
                              Amateurs study tactics, Professionals study logistics.


                              Latest Topics