From the Boston Globe a few days ago:
A boat tour under the span that connects Charlestown and Chelsea suggests it isn’t too vulnerable to a big collision.
www.bostonglobe.com
Tobin is much much much less likely to get damaged in a ship strike than the Key Bridge in Baltimore.
Much less shipping traffic under it;
Much smaller ships under it;
Piers are outside the channel, in shallow water (ships run aground before hitting the piers);
Each pier supports a cantilevered bridge section independently (fundamentally different design than the Key Bridge) -- even in a catastrophic pier collapse the entire bridge would not come down.