How do I repurpose an old metal chandelier with a nautical theme?

How about adding some shells and making a windchime? You could use varying lengths of light rope or even fishing line and add several shells on each strand. Since it's metal, it would work great outdoors. I'd give it a good coat of exterior paint first - Rust-Oleum is my preferred brand and holds up well.

I would sand the surface depending on the material it’s made of, after sanding, wipe it down with a very damp cloth. Then I would spray paint it white. For the second coat you can spray it again or I use a sponge and apply the second coat. Seal this with a matte coating to help it keep its color. You might try applying seashells at spots, or if you don’t want to paint it, get some Jute and wrap each area. You will need to find glue that will adhere to the metal if it’s metal. Glue at each end. Continue until you have it covered! You can then apply white paint. A picture would help best of luck.

After prepping the mettle leather polish or paint blue put netting all over the metal with small sea shells all over it

Kathy that was my thought as well!

You could try spray painting it blue and try hanging fishing netting from it. Or you could wrap it with rope: https://www.hometalk.com/diy/decorate/rooms/diy-nautical-rope-chandelier-2912827

DIY Nautical Rope Chandelier