Yes -- because if the boat displaces xx tons (however many tons it is) of water, then if the ship weren't there then the water would be (where the boat is now) -- and it's IMO clear that the weight of that water is being supported by the aqueduct.
I guess the boat looks relatively heavy, but it's mostly hollow.
Another way of looking at it is that the aqueduct needs to carry enough water (width and depth) to float a boat of that size.
If the boat is (eyeballing it) 60m long with 3 decks, that displaces (googles for motor yachts of comparable size) about 1000 tons order of magnitude.
I think that is a lot, compared to e.g. a big truck, which weighs only 30 tons -- but an ordinary road bridge obviously carries several trucks, and that bridge is short and stubby -- so its ability to carry the weight is not implausible.