Tell us the whole story, not just a picture. If you banged into something, get a surveyor to inspect for damage to the keel matrix and bolts, then plan repairs based on the results.
If you just blocked the boat off and it is sitting on the keel, this is not uncommon with swept aft keel shapes. The keel gets compressed into the hull at the aft end and pulled away at the front, the hull flexes a bit between the frontmost bolt and the forward edge of the keel. The sealant there eventually cracks or fails to adhere. The sealant may also be damaged by scraping or boatyard pressure washers set to exceedingly high pressure (because it gets the job done faster). Scrape it out and seal it up again. If you like, once you're back afloat or in the slings (not while the boat is resting on the keel) check that keel bolts (especially forward ones) are tight.
When you scrape the old sealant out, if any water comes out (it looks like there is some moisture in there), taste it (yum - no seriously - best analysis tool you got and it's free). If it's fresh, it's from the pressure washer and you're fine. Do let it all dry out thoroughly before resealing.