[GerritJ9]

I have a few questions concerning the modification of a ship in the sim:
1) I want to reduce the top speed from 35 to 26 knots. Is it sufficient to alter the speed in the .cfg file, or do I need to alter another file in some way? If so, which and how?
2) As part of the modification programme I have deleted the fore funnel file (cos01.obj) from the .dat file, as well as the reflect_cos01.obj file. However, after doing so I checked the modified vessel in a newly made single mission and the "deleted" funnel has obstinately remained in place (as well as remeining in place when viewing in "Museum"). Is there another file to be deleted as well? Armament changes have worked perfectly.
Thanks in advance!