@gungasnake,
This is why historical "what ifs" are so often bullsh*t. War is not a game of Risk in which one allots new resources at the beginning of each "turn" where and how one chooses. Capital ships required rigid sheet steel for armor on decks, superstructure, gun turrets and the torpedo bulge below the waterline. You don't just stroll over to Krupp and tell them: "OK, stop making armor plate and start making the low grade, flexible, thin sheet steel we need for submarine pressure hulls." Submarines also use large amounts of ball- and roller-bearings. In 1939, ball- and roller-bearings were largely manufactured in Schweinfurt, which produced two thirds of Germany's ball- and roller-bearings. Production there dramatically increased from the end of the First World War to 1943 (when the USAAF bombed Schweinfurt). A good deal of Germany's ball- and roller-bearing supply also came from Sweden. You don't just wave a magic wand and expand the production of anything which requires precision machine-tools and highly skilled labor. You don't just grab some yob off the street and tell him now you'll be a machine tool operator, or now you'll be a highly-skilled welder making pressure hulls for submarines. It would have been robbing Peter to pay Paul. German aviation plants used well over two million ball- and roller-bearings
each month.
(Source for ball- and roller-bearing production and use in wartime Germany.) Any ball- and roller-bearing production diverted for submarine manufacture would have decreased the supply for the aviation industry nnd for the manufacture of armored fighting vehicles. Submarines used diesel fuel. The German army quickly learned that gasoline-fueled tanks were potential death traps, even in the event of a hit which did not pierce the armor. Any diversion of diesel fuel to submarines would have decreased the supply needed for AFVs.
Facilities for building and launching submarines would have needed to be dramatically expanded, as well as a concomitant increase in the skilled labor force to build the submarines. This would also have taken resources away from other wartime industries, as well as skilled labor.
Finally, this silly claim is predicated on the notion that Britain could have been starved by an aggressive submarine campaign. Diverting production from capital ships to submarines would have allowed English, Irish and Canadian shipyards to switch production to to frigates and destroyers. The Royal Canadian Navy escorted more convoys to Britain than all convoys escorted by the United States Navy and the Royal Navy combined. They did it overwhelmingly with mine sweepers and corvettes--anything which could sail in blue water and drop depth charges. Those mine sweepers and corvettes were built in Great Lakes shipyards which could not have been used for larger ships. When the frigate was re-introduced into modern navies, those same Great Lakes shipyards wree able to switch to frigate production from corvette production without missing a beat.
Last of all, although a greater success in attacking convoys bound for Britain would have, temporarily, decreased the supply of war materials to British factories, the people would not have starved. Women and elderly men went out onto the land and began farming former grazing lands so that Britain dramatically increased their food production during the war. The food may have sucked, but nobody was starving.
This is just typical Gunga Dim bullsh*t--ill-considered, and not thought out, and based on profound ignorance.