What Yamato would need for a Rhine River operation

Could Yamato travel up the Rhine with giant pontoons and still fight?

Pontoons might reduce her draft enough for part of the river, but bridge clearance and near-zero maneuvering space make the mission highly impractical.

In the Strike Witches scenario, moving Yamato along parts of the Rhine is physically conceivable if pontoons provide enough buoyancy to reduce her draft. The pontoons could also add protection against attacks in the confined river. Bridges would have to be absent or destroyed, and the battleship would have almost no room to maneuver. She might have to withdraw stern-first after advancing bow-first, making the modification a desperate solution rather than a sensible use of the ship.