[OpenLayers-Users] Scale on the map in nautical miles

[Markus]

Dear OL-Specialists,

For www.OpenSeaMap.org I would like to have a map scale in nautical 
miles and kilometers (instead of kilometers and feet):

Upper side: nautical miles and down to 0.001 nautical miles
Lower side: kilometers and if less than 1 km meters.

Where can I find a scale like this?

If not:
Who can help us and would like to script a such scale?

Thanks a lot!
Markus

PS: 1 nm = 1.852 km