I would suggest that you assemble your own using stainless tube and fittings such as these:
You can find these at Go2marine.com as well as other marine
supply stores I expect.
You cut the tube to the lengths you need and use whatever fittings are required to get the look and support you want.
You can size the rail to use your existing mounting holes.
If your existing handrail was longer and had support dogs
, you can add them where needed.
Waaay better than chrome plated zinc.
The one issue you'll face is if your rail needs to curve over a long run, or has a compound curve. Long/compound bends in stainless tubing are exceptionally difficult to create without the right fabrication equipment