桶

Left tree radical - indexing radical for 桶. Buckets and barrels were traditionally built from wooden staves bound with iron hoops, so the wood classification is literal. Same wood-radical family as 板 (plank), 柱 (pillar), 桥 (bridge), 椅 (chair) - all built artifacts. Marks 桶 as carpentry.

Right phonetic 甬 - supplies the sound (yǒng → tǒng, with initial shift; same phonetic series gives 通 tōng, 痛 tòng, 涌 yǒng). Itself a graphic of a hollow tubular vessel or a bell with handle. Adds a pleasing semantic echo - 甬's tubular shape matches the cylindrical body of a bucket, so phonetic and meaning quietly reinforce each other.