If you live near a major port city, such as San Francisco or Seattle, odds are that you are also near a number of bridges. You may have traveled over them by car or by foot, but you might not have realized just how big they are. Kayaking, in addition to being an excellent workout and a fantastic way to spend a day outdoors, can also give you a new perspective on seemingly ordinary landmarks such as bridges. Since many impressive bridges span navigable bodies of water, a kayaking trip is a great opportunity to paddle underneath a bridge. There are many aspects of a bridge paddle that make it so interesting, but there are also some important things you should remember when planning a bridge paddle.
One thing you should be aware of is the likelihood of strong currents flowing under your bridge of choice. Many bridges are built over narrow waterways such as straits or channels. Particularly in the cases where these waterways connect a larger body of water to the ocean, tidal currents can be treacherous when the tidal exchange is significant. For example, currents under the Golden Gate Bridge can reach up to 6 knots during the most significant tidal exchanges. For comparison, the fastest you can probably paddle your kayak is about 2 or 3 knots. These exceptionally fast tidal currents result from the large amount of water that has to flow out of the bay, sound, or other connected body of water into the ocean during the course of the tidal exchange. From this example, you can see why it’s important that you plan around the tides so you don’t get swept away by the current.
Luckily, tides and tidal currents are very predictable, so you can check a tide chart to make sure the tidal exchanges are small when you will be out kayaking. If you pick a time when there is very little tidal flow under the bridge, you will have a much safer and more enjoyable trip. If you are comfortable with planning for tides, you may also consider planning your trip so that the tidal current flows in the direction you want to travel. For example, you might want to ride the current from your launch point to your destination, then ride the return current back to your launch point when the tidal flow switches direction.
When kayaking under bridges, you should also be aware of the flow of water through the bridge supports. In particular, smaller bridges may have spaces between their supports through which water may flow. If you get too close to one of these spaces and your boat does not fit through it, you may get stuck against the supports by the force of the water flowing through the space. The effect is much like a strong suction or vacuum. Note that it takes very little flow for your kayak to get stuck in this manner. The best way to avoid this problem is to recognize spots where it is likely to occur and stay far away from them. You should move quickly past any such danger spots, and advise others in your kayaking party to do the same.
Another thing to look out for when kayaking under bridges is the possibility of other boats in the area. Since bridges are often located near major ports, marinas, or navigable waterways, it is often likely that larger motorized boats will cross your path. As you may know already, you should never try to pass in front of them, stay aware of where they are at all times, and turn your bow so the length of your kayak is perpendicular to any large wakes caused by passing boats.
Although these are just a few of the particularities you may have to deal with when planning a bridge paddle or kayaking under bridges, the more you inform yourself, the better you will be able to avoid uncomfortable situations and stay safe in your kayak.