Once one has bombed the ports and has a decent air plan, here is what I believe to be the main issues that cause excessive Allied losses at sea in the invasion:
1. H2 293 glide/rocket bomb, radio controlled. It was a deadly weapon, but by the time of Normandy the Allies had developed effective jamming equipment against it. It has a very high accuracy in the database, and it appears that jamming either does not exist in the game or is not well applied. Cutting, dramatically, the accuracy of this weapon goes a long way to eliminate the excessive at-sea losses. I feel reducing this weapon's accuracy is justified due to the jamming equipment.
2. German pilot quality is actually higher than Allied (75 vs 70 on the main editor tab), in spite of low training hours and the extremely high losses of the previous year and a half. German training hours keep declining and have been much less than Allied training hours since October of 1942. See:
https://www.ibiblio.org/hyperwar/AAF/AA ... ffe-8.html by W. Murray, PhD. German losses in fighters were 167% in the first half of 1943, 174% in the second and a staggering 251% in the first half of 1944. Not many of the old guard have survived this and the new pilots since Oct 1942 have mediocre training to what has become by mid-43 quite poor training. They suffer especially low hours in high performance types. W. Murray states this about the newer German pilots: "Allied flyers, in their overwhelming numbers, were shooting down German pilots before they could crash their aircraft"; such is the poor quality of training. Murray's commentary justifies reducing German pilot quality and increasing Allied.
3. Numerous Allied Coastal Patrol aircraft lack historical naval loadouts such as torpedos, depth charges and mines. This is a longer subject than I have time for now, but just having bombs in some aircraft limits their naval interdiction. I have a number of links on this if anyone is interested.
I don't think game play alone will give a historical result at sea in Normandy.
Gen Dad.