minecraft-assets/data/minecraft/recipes/bamboo_chest_raft.json

{
  "type": "minecraft:crafting_shapeless",
  "category": "misc",
  "group": "chest_boat",
  "ingredients": [
    {
      "item": "minecraft:chest"
    },
    {
      "item": "minecraft:bamboo_raft"
    }
  ],
  "result": {
    "item": "minecraft:bamboo_chest_raft"
  }
}