Eyewitnesses saw "Titanic"s stern rising high into the air as the ship tilted down in the water. It was said to have reached an angle of 30–45 degrees, "revolving apparently around a centre of gravity just astern of midships", as Lawrence Beesley later put it. Many survivors described a great noise, which some attributed to the boilers exploding. Beesley described it as "partly a groan, partly a rattle, and partly a smash, and it was not a sudden roar as an explosion would be: it went on successively for some seconds, possibly fifteen to twenty". He attributed it to "the engines and machinery coming loose from their bolts and bearings, and falling through the compartments, smashing everything in their way".