The Canadian Current Atlas is one of my favorite guides which shows the strength and path of currents throughout this region. It’s useful in determining where and when to travel to your destination. Use the Washburne’s Tables to find accurate tide levels in planning your trip. Both guides should be used together. Fundamentals of Kayak (or SUP) Navigation is an essential guide in figuring out currents, tides, and paddling in both. Find both at Starpath.com.
If you’re planning a paddling trip in the San Juan Islands, BC Gulf Islands or similar, there are a few guidebooks (aside from mine) which are essential for a safe journey. Tidal currents are quite strong in those areas especially in Haro and Rosario Straits and the outer San Juan Islands. Many deaths and rescues have occured here from poor decision making in negotiating (or not) the tidal currents.