I think there's something wrong with your NYGM installation.
Did you the steps listed
here?
The correct
Campaign_RND.mis is contained in
NYGM3_New.7z and includes the
M36B entries.
Extraction:
...
[RndGroup 64.RndUnit 49]
Class=M36B;;CAM-Ship
Type=8;;102
Origin=British
Side=0
CargoExt=0
CargoInt=0
CfgDate=19380201
No=1
Escort=false
SpawnProbability=100
CrewRating=3
...