Didn't use the deck gun - I used torpedoes. Each ship took two to sink.
I was thinking about what caused the problem. It is important to note that some of the parts of these ships were moved using Wings3d instead on Pack3d (they are older work from last fall). But even parts which were not moved this way (such as funnels) did not collapse. The ships also didn't break in two, even though all three exploded. Also, all parts are indeed separate .obj's from the hull.
Thanks for the compliments, BTW.
I was wondering if these three ships would gain any interest. I was going to release them tonight, but I can see some parts that need to be fixed anyway. And I might move the masts back to their original places and move them correctly with Pack3d.
(Also, I should note that the Heavy Merchant is using one of Iambecomelife's skins from the MVP. The Kyle skin is stock.)