Have posted in a few threads here regarding the larger-than-battleship ships pictured in Horus Heresy Collected Visions and have decided to move forward with the modeling project. My primary interest is Mortarian's Death Guard Fleet, but other legions also had these larger ships. This first post is background with modelling continuing in the second post.
Some examples of the large ships:
Double stacked weapons bays
Death Guard Stalwart
Emperor's Children Erehwon
Mechanicum Aratan
Triple stack weapons bays
Death Guard Reaper's Scythe
Word Bearer Balthamirs Sword
Death Guard Rage of the Damned
Silly stacked weapons bays
Sons of Horus Vengeful Spirit