So, I grabbed one of the separate engine pieces that come for the battleship miniature and made a two-piece rubber mold so I could cast some extra engines parts:
This is my kitchen work area with three engines cast and another one cooling in the mold:
The original engine piece from the box, and four shiny new engines hot off the stove:
Cutting off the one original engine from the official mini and prepping the two new ones:
All done, looks pretty nifty I think!