for added realism paint it a rust colour before the paint fully dries sprinkle on a little salt, once the paint has dried paint with 2 coats of top colour. Once they dry lightly sand and wash with water. the sanding breaks the paint over the salt and water washes it off.

Now you have rust spots. if you HATE the effect a layer of topcoat wil cover it.

Thanks for the replies Haverlock thanks for the link to many choices .Stevedanter it is a wartime craft so chrome will be a bit flash have used brass wire and painte it.To use the old saying if it don't move paint it

Since there is not just one marque of HDML but many and various I see no problem with your handrail. if you have any lingering doubts I can only offer

http://www.bing.com/images/search?q=hdml boat&qpvt=hdml boat&qpvt=hdml boat&qpvt=hdml boat&FORM=IQFRML

More images than you can shake a stick at showing the variations in craft.

Not sure what a HDML is , but I used a thin chromed wire for mine, it seemed more to scale for what I was doing