Tides

Admiralty Easy Tide Admiralty Easy Tide
BBC Tides BBC Tides

Weather

BBC Inshore waters BBC Inshore waters
BBC Shipping Forecast BBC Shipping Forecast
BBC Coastal Forecast BBC Coastal Forecast
BBC Surf Reports BBC Surf reports
BBC Coastal Observations BBC Coastal observations
Met Office Met Office
Met Check Inshore Met Check Inshore
Synoptic Charts Synoptic Charts
Mountain Weather Mountain weather

Forums

LSKC Yahoo! Group Sea Kayak Guidebook
Sea Kayak Guidebook Sea Kayak Guidebook
The Kayak Forum The Kayak Forum
SCA Forums SCA Forums

Maps

Google Maps Google Maps
Google Earth Google Earth
Multimap Multimap
OS Getamap OS Getamap

Some useful safety documents can be found here:

Safety & Planning Summary Sheet

Trip Planning & Safety Resources