Interesting little artistic problem.

I would find a piece of closet pole etc. and fill the openings (epoxy them in) . then I would get some contrasting veneer - something dark or light with a flamed grain look and veneer with epoxy the bow and stern ends covering the openings. This would be a "V" shape and might end with a "S" curve. Draw a pattern up tht looks nice to you. Then re- drill small openings through the closet pole stock. (drill in from each side meeting in the center to get the entrees correct. Start with a 1/8" drill.

You're probably staring at it too much. It might be fine. Maybe just a wood plug with a smaller hole??