Give em some of these withe the neck rest. Imagine amphibious roman chariots. Or a horse powered pontoon boat.
There’s a lot of cool images here https://liberalarts.tamu.edu/nautarch/nwl/lake-champlain-projects/hoofbeats-over-the-water-ina-research-on-horse-powered-ferryboats/
Can’t access it and the archive links miss the article text too 🥲