Crossing a Coastal Bar
Coastal bars (shallow banks formed by the movement of sand and sediments) build up at the seaward entrance coastal rivers and lakes. They cause waves to become steeper and, in some cases breaking as they approach the bar. There are many bars along the Australian coastline. Even on a good day, conditions on a coastal sand bar can change quickly and without warning.
Only experienced boaters should attempt to cross a coastal bar and, even then, caution should be exercised.Observe the wave patterns and conditions prior to crossing. (Walk down to the break wall) Learn what you can about the characteristics of the bar you plan to cross from locals or volunteer marine rescue groups.Make sure you ask about any leads and beacons that may assist in navigation over the bar. Become familiar with a bar by crossing with an experienced operator before attempting a bar crossing by yourself. Ensure your vessel is seaworthy and is capable of taking some impact from waves. Conditions offshore can be ideal for boating but the conditions on the bar can be dangerous due to swell.Do not attempt a bar crossing in heavy swells and strong wind. Avoid crossing a bar on a run-out tide when the most dangerous wave conditions usually occur. Be prepared to cancel or delay the crossing.
Be aware that a rapid change in conditions might prevent a safe return. Obtain a weather report and check the tide times for when you intend to cross the bar. Vessels unable to weather adverse sea conditions outside the bar should not leave port.Make sure that you have adequate reserve fuel and provisions should you need to remain at sea longer than intended, or need to divert to another port.
File a float plan - let some one know what you are doing and your estimated time of return.Watch other vessels make successful crossings.Wear polarised sunglasses - they may help you to judge the deepest water and best route. Check that everyone on board is wearing a Type 1 lifejacket and is seated prior to crossing. Check that windows and hatches, lines and any moveable items are secured. Ensure correct trim. For bar crossing your motor must be trimmed all the way down to ensure maximum control of your vessel during the crossing. Test all controls - steering, bilge pumps, engines, fuel, filters and radio battery. Use your marine radio to log on and off with your local VMR informing them of the name of your vessel, description and how many persons are on board.Check the state of the tide (it is safest to cross on an incoming tide). Observe water patterns and sets to establish when calmer periods occur. Look for the deepest water of the channel.Look for a position marker or lead so the entrance can be located on the return trip.
The skill of crossing a bar is to know the best water by judging the wave pattern, crossing at the calmest point and manoeuvring the boat around breaking waves. Look for the deepest water or channel. Be patient and watch the sets of swells before choosing the best time to go. Once committed, keep going - attempting to turn around in front of an incoming wave can be disastrous. Do not hit the waves at high speed; take them as close to head on as possible. Some bars have waves breaking across the whole entrance and finding a way through may be practically impossible. Be prepared to take a wave head on and take water over the bow if you find yourself in a position where there is no alternative. The boat must match the energy of each incoming wave by maintaining a speed that will lift the bow over the wave, and reducing the likelihood of the wave breaking over the bow and into the boat.
General principles for bar crossings may include:
Idling towards the breaking waves, looking for lulls, select a line of least wave activity, apply throttle and run through.Keep your boat generally bow-on as the waves approach and do not let the boat turn sideways (broach) to a breaking wave. Head up into the waves and bear away quick on their backs.Accelerate where possible, but avoid getting airborne. Head for the trough of wave (the gap between the waves) between peaking waves about to break. Navigate quickly clear of the bar.
Lay off from the bar and observe the direction and set of the waves. Radio your local Volunteer Marine Rescue (VMR) Unit and inform them that you are returning to port and are about to cross the bar. Locate and identify entrance leads and line your vessel up on these leads prior to commencing your crossing.Watch for patterns and deeper areas. Adjust the boat's speed to match the speed of the waves but do not attempt to overtake the waves. Displacement boats may have to come in very slowly to avoid surfing and broaching-to (getting caught side-on to a wave). In extreme conditions, the very difficult but vital decision not to come in may have to be made. It may well be safer to stand off in deeper water until conditions improve or to seek alternative shelter.
Safety points to remember
- Never underestimate a coastal bar. Even small waves can capsize or swamp and sink a boat. If you are unsure or inexperienced, why go out and risk lives?
- Wait until conditions provide a safe crossing that you can handle.
- Know where the deepest water is and cross during the top of the tide to ensure you don’t risk running aground.
- Watch for a sufficient time to assess the wave patterns and where waves break the least.
- Wear life jackets while crossing a bar in any boat at any time. Remember, it is compulsory for everyone on board to wear a life jacket when crossing a designated coastal bar. A capsize can happen quickly and trying to put on a life jacket while in choppy waters is almost impossible.
- As a skipper, think of your crew and passengers and don’t take risks.
- Choose your route across the bar carefully and avoid the high standing waves.