There is an APP for iphone supporting those webmaps but you can only see where you are and thats it.
This feature and the Pathaway navigation capabilities would be a perfect match for yacht sailing (in addition to traditional paper maps of course

Since OpenSeaMaps is a sub project of OpenStreetMaps it would hopefully be no huge task to add support for those maps.
I would be very happy to see this feature in one of the next releases
Thanks in Advance to the development team
Best Regards
Harald