This last Segment consists of legs 17 through 21 of the Lower Basin of the 310 mile long north flowing river. It is the longest flowing river in Florida.  Water levels on the river vary considerably with rainfall amounts and tidal action. At this point strong tidal currents become an increasingly important consideration the closer you get to the mouth of the river. Plan to use them to your advantage by riding the outgoing tide. It can be almost impossible to paddle against the tidal surge. Stay out of the channel and along the shoreline where possible. Remember to stay at least 100 yards away from military vessels. Wind can be an important factor on some of the wider parts of the St Johns. Always make sure to carry plenty of water and food. Make sure you leave a good float plan. Carry good maps, a compass and GPS. This Segment is recommended for advanced paddlers only due to strong tidal currents, heavy powerboat traffic and exposure due to the width of the river.