KanjiJLPT N1
Gunwale

Mnemonic

The gunwale of this boat pulses with a mysterious glow every night. Sailors refuse to touch the gunwale after dark, swearing the mysterious light burns anyone who grips the boat's upper edge. Yet each dawn the glow fades, leaving only charred handprints along the rim.
Additional thoughts
Picture the boat's top rail glowing an eerie, mysterious blue-green — your hand reaching toward it then pulling back from the heat. The charred handprints reinforce that this edge (gunwale) is real and dangerous.
Quick recall
A boat's edge pulses with mysterious light — that cursed rim is the gunwale.

Details

The keyword for 舷 is gunwale. This kanji refers to the upper edge or side of a ship's hull, known as the gunwale (pronounced "gunnel"). It denotes the part of a vessel where the deck meets the side, serving as a protective rim. In broader usage, it can refer to the side of a boat or ship in general.
On'yomi
げん
Kun'yomi
ふなばた、ふなべり