IXA: 8 cmissioned
IXB: 14 comissioned:
IXC: 54 comissioned
IXC/40: 87 comissioned
IXD: 30 comissioned
Thats, 193 type 9 uboats.
verses:
VIIA: 10 comissioned
VIIB: 24 comissioned
VIIC: 568 comissioned
VIIC/41: 91 comissoned
Thats 693 type 7 uboats.
Now if one were to look at the top scoring uboats:
http://uboat.net/ops/successful_boats.htm
13 out of 20 are type 9's. Thats over half of the top earners.
If one were to look at the top scoring patrols:
http://uboat.net/ops/top_patrols.htm
Only 3 out of 20 uboats were type7's, the rest are type 9's.
From this, coupled with the fact that type 9's did attack convoy's just like type 7's, and that as a class they achieved these tallies with FEWER ships of their type, says something about their overall effectiveness as a class.