That's "Bruce Palmer modal tuning" down two steps: C C C C G C
Holy mukluks Batman, I'm surprised there's still enough tension to drive the top at such a drop.
Oh, just realized I'm operating on the assumption we're starting with a dread with strung with lights (.012's)
Having kept my F65ce at "D", only a whole step down for the last 6 months or so, I'm pretty darn sure it wouldn't even be playable 2 steps down.
But I
was going for low tension using Silk'n'steels too, and didn't want to drop more than a whole step anyway.
But for the first 5 minutes I thought it wasn't going to work.
It was definitely muting out.
It's funny but over about 20 minutes it seemed to adjust to the new lower tension and the next day was fine, albeit a little quieter.
Sustain was better, though.
I guess if I went to true mediums it'd be OK at C standard.
Might even be a reason to use heavies, on a dread.
Something to bear in mind if you run into the "too floppy and doesn't even ring" problem.
In fact, thinking about it, I've actually had the D25 at "D standard" for the last 6 months too, with the .012's , and pretty sure it'd mute out at "C", too.
Other makers guitars may vary, of course.