h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I once asked Jeeves (the search engine) where I could buy Tide Timetables. He asked if he could check my spelling.

They're difficult to get hold of for amateurs. We eventually found somewhere to order them but they took months to arrive.

There are a couple of free tide table generators. I'd give you the URL but I can't here.
Try searching for xtide and wxtide at your favourite search engine. Unfortuantely if you're in the UK then the UK data has had to be removed at the insistance of the UK agency responsible for it
Where are you located as chandlers and many places by the coast sell them.

I'm in the UK so I guess those generators won't work. I'm also in landlocked Shropshire so no chandlers either. I'll just keep my eyes open when we're at the coast - for tables and tides. Sometimes its nice to know before you get there where the sea is going to be.