Before the gangway collapsed, officials said there were upwards of 40 people standing on it. But the Georgia Department of Natural Resources told Action News Jax’s Atlanta station WSB-TV that its engineering firm calculated that it should have been able to support the weight of 320 people. Here is how the engineers reached the calculation.

Emotional accounts from relatives of the victims and survivors of the partial collapse of a boat dock gangway on Georgia’s Sapelo Island and a newly released video of the frantic rescue efforts paint a dramatic picture of Saturday’s incident.