Andi Nagasia, on 19 June 2015 - 07:57 AM, said:
What is your source (an actual sourcebook or novel, with page and/or chapter number) for this?
The closest there is to allowing this in the TT rules is the FrankenbMech construction rules found in
Strategic Operations.
"Internal structure critical slot distribution is retained from the donor design or, if no critical slot of the appropriate internal structure type is present, the number of critical slots listed on the Internal Structure Distribution Table" - StratOps, pg. 189
"Any OmniMech components incorporated into a FrankenMech will lose all benefi ts and special abilities associated with OmniMechs. They cannot be reconfigured with alternate pod load-outs. A FrankenMech cannot carry Mechanized Battle Armor." - StratOps, pg. 190
Even the advanced customization rules (also found in
Strategic Operations) don't seem to allow for this:
"Generally, players must follow
Classic BattleTech construction rules when customizing a unit. A player cannot simply strap a couple of new medium lasers onto an existing design, as this would make the unit two tons too heavy. Other components must be removed or changed to make the appropriate space and weight available for new systems. However, players need not observe the standard construction prohibition against mixing technology bases when customizing units. Clan parts can be installed in Inner Sphere units and vice versa, though such modifications may be a bit more difficult than standard replacements. All other standard construction rules still apply." - StratOps, pg. 189
Even on a "standard" (that is, non-OmniTech) BattleMech, replacing the structure would be a Class F refit ("a long and involved process that requires a production facility capable of producing the unit in question"; see page 188-189 of StratOps).
Moreover, neither
Master Unit List nor
BattleTech Engineer has any listing for a special configuration attributed to Ranna Kerensky, which would indicate that her 'Mech was built on one of the standarized configurations.
So, it is highly unlikely (to say the least

) that Ranna's
Masakari had an Endo-Steel internal structure.