Convert your Shapefiles (must be in a .zip containing .shp, .shx, .dbf, .prj), .kml, or .gpx to standard EPSG:4326/WGS84 GeoJSON format using this tool.
Select the target output name (exactly reefs.geojson or wrecks.geojson) and click Download.
Upload the downloaded file to your server at exactly: C:\map.scubaviz.us\data\vectors\
When the corresponding checkbox is active on the map page, the map will automatically fetch and draw the updated data.