The alphabet is "Monterrey BT" and is from SewForum but sadly, it's no longer available on the Forum.
And my little pirate tag: SewForum.com is a machine embroidery forum that I participate in.
They have a section where participants can upload designs that they have created for the use by the rest of us. There are some very, very talented amateur digitizers out there! One such generous person digitized a VERY small skull-and-crossbones.
Well, I collect virtually everything piratey and I've had this one for some time. Sadly, I can't find it on the forum any longer, so it might have been removed. In any case, it's VERY small ... less than 1/2" square.