denise, I've been on the DUCs and they're perfectly up to the job they are used for. If the DUC had been any other type of single-engined boat, a jet boat, a cruiser, a (purely) sail boat, the outcome would have been the same.
The vessel had an engine failure and it only has one propulsion engine. That left it dead in the water, unseen by a barge coming down a main channel. Sailboats and power boats get run over the same way, all over the world, every year.
Now, in 20-20 hindsight, maybe the DUCs and every other single-engine vessel should be prohibited from entering or crossing shipping channels. But there's also the matter of whether anyone on the tug was keeping a proper lookout, visually or on radio.
DUCW? Fun ride! And they're not just old clunkers, there's been a lot of money spent on building the new ones.