What if: Nazi ufos

[Sea Skimmer]

Large areas of harbors, even ones made up of enclosed docks, are open water and the water is generally in the center of your target area which is rather annoying. The Germans couldn't shutdown any of the British ports during the Blitz, don't expect UFO raids of 20 tonnes of bombs each to do any better. Disruption sure, but in the end the end as I recall less than 1% of unloading time and shipbuilding effort was actually lost in the Blitz. Might have been a little higher, no time to looking a book right now, but it wasn't very much.

The problem is compounded because if you want to sink ships you need to drop bombs with delay action fuses, but that will mean they do much less damage to the shore facilities which are more likely to be struck. A fuse that goes off on impact will damage a ship, but its going to be damage on the upperworks that doesn't make it flood.

[madd0ct0r]

droppint anti-ship mines more viable?

[Sea Skimmer]

Mines are useful, you can fuse them so they explode if they strike a ship or land directly, and still sink to the bottom to be mines upon striking water. By June 1944 the Germans get 240 x UFO assuming zero losses and none simply becoming worn out, and the desirable mines would be in the 500 and 1000kg range which means decent numbers can be carried. It might be enough to strangle the British with good luck, but they have an awful lot of harbors. Also by that point the full resources of the USN and US merchant production are in play to keep traffic flowing. Mines laid in harbors would be obvious and even an 'unsweepable' late war pressure mine can be cleared with explosives if you already have a good idea as to its location. For the USSR in the war depth charges were the primary means of clearing German bottom mines. Its expensive, but the western allies had silly amounts of explosives. Early war, I don't see enough UFOs to accomplish very much in any role. Certainly not in bombarding British ports which already withstood thousands of tons of explosive and hundreds of thousands of incendiaries.

One thing sustained heavy bombing and mining of UK ports would do if nothing is make an cross channel attack extremely difficult to amass.