I would dampen it with tepid water and then sew it with some sturdy thread. I've seen it done on drums before. It looks great and it seems to allow the heads to be used and it doesn't have a drastic effect on the sound. It IS skin, after all, so it's just like getting stitches.

Thanks for the response! I tried moistening the skin a little around the rip and sewing it up in a cross-stitch pattern last night. I could not get the skin to stretch enough to close the gap 100% but it looks better than before. I will let the skin dry out, then reset the head and give it a go. I will update in a week or so after the head is back on and has been tested a little under working conditions.

Well, the repaired calf skin head has performed fine through almost a month of use. Granted, I used it as a resonant head rather than a beater but the repair has held up fine under tightened/tuned conditions with no further tearing. I am particularly happy given the head has been through a variety of moisture conditions over the past weeks (Wisconsin summers) but has given no obvious sonic indication of being previously torn. I may try it as a beater head someday but I am leaving where it is for now. Thanks for the advice!

Hey, that's great. Yeah, I had the same situation -an old transition badge bass drum as original as the day it was built except the front head was cracked fron top to bottom. I figured I had nothing to lose. When I started, the cracked part was all splayed and wrinkled. After I got it dampened, I was able to sew it allllllmosssst together...but not quite. Just like your results, the head performed just fine even with the crack. Plus, I thought it looked interesting, too -a definite conversation piece!. I'm sure there are ways to do it so that the whole gap could be sewn back...but Iwasn't skilled enough at the technique.

Thanks for checking it out!