Complex sentence: Comparing the archaeology of German submarine wrecks to the historical text, which shows the extent to which archival sources relating U-boat war losses in UK waters differ from the actual distribution of known, surveyed and identified U-boat wrecks.
Split into simpler sentences: Comparing the archaeology of German submarine wrecks to the historical text. It shows the extent to which historical sources relating U-boat war losses in UK waters differ from the actual distribution of known, surveyed and identified U-boat wrecks.