I believe it might have been less than 30 degrees. The hull could have split at a lower point if it was weak enough... The baker for example did not report a sudden drop (ellivator drop) as depicted in the movie. Certainly if something as heavy as the stern of a ship were to drop from so high up, it would have left a few people hanging in the air for a moment. That was not reported. If it broke apart at a lower hight, people would have felt a less dramatic fall and thus be able to hang on to the stern as it fell back on it's keel. That seems to be evident from many survivor accounts.