Well it's a bit hard to understand out of context but I think It's talking about a ship that went to war(perhaps USS Arizona in the bombing of pearl harbor) and Magee says that the kids can understand enough to know that the boat was hurt while fighting for them maybe by relating to the fact that they have been hurt before or that the ship made a sacrifice to keep them safe. Is this answering your question? or am I overthinking it in the wrong direction or something. Just comment or pm, I am happy to help.
