Hello,
I compiled geofabrik.de Ireland OSM data with mkgmap (I made my tests with source code downloaded 2010/12/17)
and the sea is generated only for one tile with "generate-sea=multipolygon,close-gaps=1000" but works well with
"generate-sea=multipolygon,extend-sea-sectors,close-gaps=1000" !
With mkgmap version from august, it works well. Did you change an
option for sea generation ?
I also found two small problems with mkgmap's options :
Option -version does not display a number but "svn". This is the
same with old version (since 156x, I think)
While I noticed you changed some options name, I found a annoying
change : when mkgmap meets an option which is not needed for
compilation phase, it stops with an error message like "invalid
option". This happens only with "product-version" option.
Thank you for your great job,
David