bole of a tree, cross-beam, combing round the hatches of a ship
檁 centers on a structural wooden beam, especially a cross-beam or the main bole of a tree used as a beam. The ship-hatch sense is a specialized application of a wooden cross-beam used in ship construction.
檁 combines 木 (tree/wood) with 稟, which likely contributes the sound リン and may relate to a granary or storehouse, suggesting a wooden structural element. The exact historical development is uncertain.
The left side is a tree 木, and the right side 稟 looks like a storehouse with a roof and stacked grain. Picture a massive wooden beam, cut from a tree bole, used to support the roof of a storehouse.
For リン, imagine a long wooden beam ringing like a bell when struck: ring -> リン, and the sound echoes through the ship's hatches.