Here's the 42b Convoys and Merchant layers merged
The 43a layers would be very similar, with a "thinning" of the lines for 44a & 44b layers. It is very similar looking to the pattern displayed on the map available in the Control Room from the Shortwave Radio link above the Chief's station:
The screen resolution on my laptop (Widescreen) is not able to show the whole map, but it does move around with a click and drag of the mouse.