PS: Thank you for the reward of the book friend "My feelings after reading this book" and the monthly ticket voted by the book friend "zkn" and "qxg", I hope that the disaster will not die, and there will be a blessing ^_^

However, in the absence of a good way to deal with Germany's anti-ship missiles, bomb-making and jet fighters and other new weapons for the time being, the US aircraft carriers do not dare to get too close to the Western European continent, so it is impossible to open up a second battlefield for the time being, and can only try to resume strategic bombing of Western Europe after Britain restores its fuel reserves, after all, although Germany's jet fighters have excellent performance, they are too few in number, and the range is relatively insufficient, it is difficult to protect the whole of Western Europe, and the B-29 is still promising under the protection of P51D

The US Navy, on the other hand, has adjusted its strategic direction and shifted its focus back to the Pacific Ocean, intending to take action against Japan after the aircraft carrier is repaired, so as to prevent Japan from further digesting the land it occupies and making it more difficult to counterattack. However, before that, the U.S. military still needs to deal with Argentina, the anti-backbone, in order to reopen the road to the Pacific.

The timely completion of the two Montana-class giant battleships played a crucial role in the settlement of the South American problem, and after a "goodwill visit" to Rio de Janeiro by six US Navy battleships, the Brazilian government, which had been hesitant, finally made up its mind to turn to the allies. Brazil, the largest country in Latin America, immediately caused a domino effect in the entire Latin American region, and those countries that were already more pro-American followed suit, even those anti-American countries were all honest at once, although they did not immediately reverse their stance and join the alliance, but they all emphasized their neutral attitude during this world war.

So. Argentina has fallen into unprecedented isolation in Latin America, and the German high seas fleet is unable to come to the rescue, although Dönitz has sent some submarines to re-operate on the "big slash", but due to the successive accession of Brazil and Uruguay to the alliance, the US fleet can completely stick to the coastline to go south, in this shallow water, the concealment of submarines will be greatly reduced, low-altitude cruising aircraft can even detect underwater submarines through the naked eye, in this case, the teardrop-shaped submarine and the old boat-shaped submarine is actually not much different. Naturally, it is difficult to pose a substantial threat to the supply lines of the US fleet.

Speaking of Dönitz, it's still interesting enough. In order to strengthen Argentina's determination to resist, he sent ten submarines to harass the supply lines of the American fleet, knowing the danger. However, Dönitz's luck hurt his subordinates, and in the end, almost all of the ten submarines were lost, and only 2 returned safely. And what's even worse is that. The U.S. military successfully forced the landing of a teardrop-shaped submarine. As a result, a large amount of valuable information and technical information has been obtained

After seeing the drop-shaped submarine, the senior generals and technicians of the US Navy were all amazed by it, and President Roosevelt immediately ordered it to be imitated. But the former heroic captain had to tell the truth to Mr. President with regret. "It should be possible to imitate it, but the operation and tactics of this submarine are very different from the old one, and it is necessary to reformulate the training program and operation manual and conduct targeted training for officers and men on active duty, and even if everything goes well, it will take at least a year and a half to initially form combat effectiveness."

When the war was fought in 1944 and the US economy had almost completely completed its mobilization for the war, it was undoubtedly unwise to invest a large amount of manpower, financial and material resources in a project that would take a year and a half at the earliest. However, the strong national strength of the United States still made Roosevelt decide to take a two-pronged approach, on the premise of maintaining the scale of the existing submarine department, to carry out research on drop-shaped submarines, and then gradually replace the old ship-shaped submarines after they have formed combat effectiveness. This will undoubtedly cause a huge waste, and the United States is probably the only country in the world today that can have such national strength

Compared with the slower-effective submarine imitation, personnel training, and tactical changes, the more direct benefit of the U.S. Navy's capture of the teardrop-shaped submarine is actually to understand its various performance parameters, so that it can formulate some tactics and strategies to deal with it. Although even the technical staff of the U.S. military praised the design of the German teardrop-shaped submarine as perfect, the U.S. Navy's technical staff, which is the world's number one, found something to use

For example, they found that although the drop-shaped submarine has a very fast underwater speed, due to the limited capacity of the battery, it cannot drive far at this high speed, and although the snorkel can make the endurance of the drop-shaped submarine underwater not limited by the battery capacity, the snorkel itself also has many limitations, which can be used well

For example, the snorkel cannot withstand too much water pressure, so the submarine can only drive to a speed of a few knots at most in the snorkel state, which is not much different from the old boat-shaped submarine, and the submarine's diving depth is also greatly limited, which greatly weakens its greatest advantage -- concealment.

Although the Germans skillfully used the radar wave detector mounted on the top of the snorkel to warn the approaching aircraft in advance, this mechanism could be used by the US Navy technicians, and in turn the Germans suffered from their own suffering.

Later, the US Navy took advantage of the fact that the radar power of the early warning aircraft was much greater than that of ordinary airborne radars, and let them patrol back and forth in the sea areas where German submarines were active, and as a result, all German submarines were so frightened that they all honestly hid in deep water, and it was rare for them to float up and stretch out the snorkel to start the diesel engine to charge the battery, so that it took several days or even more than ten days for the battery to be filled again in a similar way of gathering sand into a tower, resulting in a sharp decline in its combat efficiency, which was once reduced to less than one-tenth of its previous level.

At the same time, the US antisubmarine planes no longer turn on their radars when conducting antisubmarine searches, and they rely purely on the naked eye to search for submarines, and the results of the battle have increased markedly. On the one hand, this is because German submarines are unable to evade them in time, and on the other hand, because German submarines are "deterred by radio waves" by US early warning planes, they are forced to frequently repeat "floating up and sticking out their snorkels -- retracting and diving." And being in dangerous shallow waters for a long time naturally greatly increases the possibility of being discovered by US planes

The Germans did not discover the problem until several months later, and had to take the risk of removing the radar wave detectors, and the situation improved, but the loss rate of the submarines more than doubled, especially after the Americans noticed the change in German tactics and reactivated the on-board radar of the anti-submarine aircraft. And even Dönitz has no way to do this, only to "choose the lesser of two evils", and it is better to lose more than not to play a role (to be continued......