My process for Coffin Ship was to write a piece of instrumental music that I felt embraced the themes and characters of the work and then extract motif and moment from it. I also did a nightmare cover of Whisky in the Jar that I extracted melody and themes from. None of these played in their entirety, but snippets of them -- and their variations -- were sprinkled through the entire work.
The Coffin Ship theme. Only played in its entirety to accompany a massacre. Mostly written to extract motif and texture from.
My cover of Whisky in the Jar. It doesn't work as a song anymore. By lowering the tempo it loses its momentum and I never fixed that. But I never wanted it as an entire song, I just needed snippets of it. Nonetheless here it is in its drudging entirety.