The speaker in "Merman" seems to be asking for guidance, and the odd part is who they want it from. "Take me to the dolphin" sounds like a request to be led to someone who knows the water. The poem then compares a good husband to ballast, the heavy weight that keeps a boat steady. That's a practical, even slightly unglamorous kind of praise: he is useful for stability, and he understands "sea-business" and "the ice."
The feeling here is hard to pin down, and that's part of its pull. The speaker rows and looks, which suggests patience, watchfulness, and a bit of longing. The last line, "His is a serious art," shifts the tone toward respect. Judging by the imagery, the dolphin may be a figure of skill or intuition, set against the husband's steadiness. The mood is quiet, cool, and attentive, like watching the sea for a sign.