by T. A. Gardner on 10 Mar 2007 16:25
To date we've seen various armament combinations on the German barges, tugs, and other vessels making up the Seelöwe invasion fleet. On the barges one could expect possibly a 2 or 3.7 cm AA gun and possibly a field artillery piece lashed down on deck. Both weapons would be army models. The photo Leandros posted earlier of such a barge shows that the field piece would be virtually worthless as a defense weapon, having a limited field of fire forward. It obviously is mounted to allow some degree of fire support during the landing.
The 2 or 3.7cm would be useful as an AA gun. Its accuracy would not be appreciably worse than that of a purpose mounted naval weapon of the same size. The crew would also obviously know how to fire on aircraft effectively. They might have limited fields of fire forward (the artillery piece is there) and aft (any cabin or if the aircraft engines are mounted) against low flying aircraft too.
As for machineguns used by the passengers, these would have little more than moral value as defensive weapons against aircraft. First, it is now being pointed out that the holds on most of the barges were covered. This means the passengers have limited or no ability to see what is going on, not being out on deck. But, if we assume some of them come on deck to use machineguns they would be firing from extemporized positions. Further, they will lack AA sights and training in air defensive fire.
Also given that both the barge and target aircraft are moving introduces a paralax error making leading the target much harder. This will effect all of the AA defenses. Even the 3.7cm crew will not be familiar with this problem as it does not occur on land where their gun is stationary.
The other problem is ammunition. How much is carried and what is the intended use? For the machineguns this will be very problematic. The only figure I have for a comparable weapon is for 1st US Army from D-Day to VE day using .50 AA guns (ie the quad .50 mount). Here gunners used 21,897 rounds per kill for 129 claimed . Obviously, the number of rounds expended for the much less capable German 7.92mm machineguns will be even higher. If liberal usage of passenger machineguns is made there quite likely will be a machinegun ammunition shortage if the invasion does manage to land.
The same problems apply to any weapons on tugs or other vessels as these would be similar in capacity.
So, one can see that it is possible that the invasion fleet could put up some degree of air defense. Much of it would, like early WW 2 naval air defense in general, would be a deterent rather than casualty causing. Against determined aircrews the defenders are definitely at a disadvantage here. Their slow moving ships and barges make much better targets than the aircraft do to the defenders guns.
Against surface vessels, the weapons proposed to date as being on the German barges etc., are next to worthless. They are just too small and too inaccurate in this role to be of much defensive value. For example, a British destroyer firing time fuzed 4.7" HE low over a barge train would rather quickly cut down the exposed crews of these guns. Splinters from such rounds were a very real threat. Note how quickly every navy adopted splinter armor and such things as splinter mattesses on their ships. The barges, and possibly the tugs, have an additional problem. An actual hits are going to be magnified in effect by wooden construction where it exists. Unlike steel which will produce some secondary splinters, wood produces alot, including some very large, secondary splinters. Against vehicles and equipment these are not a big threat. But, against personnel they are often deadly. One need look no further than air burst artillery used on troops in forests in land warfare to see this. One or two large caliber naval rounds would be more than sufficent to turn a barge into a shamble.
