OSM OpenCPN MBTiles are not rendered in Freeboard-SK

CREATE TABLE tiles (
            zoom_level integer,
            tile_column integer,
            tile_row integer,
            tile_data blob);
CREATE TABLE metadata
        (name text, value text);
CREATE TABLE grids (zoom_level integer, tile_column integer,
    tile_row integer, grid blob);
CREATE TABLE grid_data (zoom_level integer, tile_column
    integer, tile_row integer, key_name text, key_json text);
CREATE TABLE sqlite_stat1(tbl,idx,stat);
CREATE UNIQUE INDEX name on metadata (name);
CREATE UNIQUE INDEX tile_index on tiles
        (zoom_level, tile_column, tile_row);

CREATE TABLE metadata (name text, value text);
CREATE TABLE tiles (zoom_level integer, tile_column integer, tile_row integer, tile_data blob);
CREATE UNIQUE INDEX tile_index on tiles (zoom_level, tile_column, tile_row);