TIDES & CURRENTS

Tides

Have played in the beach for more than 6hours? Did you realise the same spot that you were playing become dry? Where is the water? When I was young, I thought it was magic but as I grow older than I understand that these changes are called tides due to the result of the gravitational pull of the moon and to a smaller extent, the sun.

Tides affect divers by exposing or concealing rocks that are or near the water's surface. For example, a low tide may expose rocks that make the entry and exit hazardous, but when the tide rises, these rocks may be completely submerged and safe to swim over. You may also avoid long surface walk if you are diving in high tides.

Currents

In the ocean, currents are formed by winds, waves, tides, and the rotation of the earth. In the northern hemisphere, currents move clockwise and in the southern hemisphere, current move counterclockwise.

As divers, we need to know the different kind of currents and to response correctly to avoid any accident. There are few currents that I would like to share with you; Longshore, Rip & Tidal Currents. 

Longshore Current

Longshore currents run parallel to shore. Like offshore currents, they are considered standing currents, which means they rarely change direction if ever at all. It can move you far from your entry or planned exit location. To avoid a long surface swim or losing your dive party, you must determine the direction and speed of the current and plan your dive accordingly.

There are several indicators that can help you determine the direction of a longshore current. One indicator is the direction from which waves approach shore. If the waves approach the shore from the south, the current is likely to come from the same direction. Another indicator is the direction anchored boats face. Most boats are anchored from their bow, so they face against the current.

Rip Current

Rip currents move perpendicular to the shore, and are common at most beaches. These are transitory currents, which means they can suddenly appear without warning. Rip currents are form when backwash from surf is forced to travel back into the water through a narrow passage such as a reef or sandbar. They are identified by a stream of foam traveling away from the surf zone.

While rip currents can be too strong to swim against, they are also quite narrow in size. If you become caught by one while trying to swim to shore, the best response is to swim parallel to shore until you exit the current. Some rip currents can be beneficial. If you are surface swimming to a dive site, a rip current can assist you during your swim and carry you closer to your destination.

Tidal Current

Tidal currents form when incoming or outgoing tides force water through a narrow passage. Since tides move in and out several times a day, the direction and force of tidal currents changes throughout the day. Currents of this type are often too strong to swim against, so careful planning is required before diving in areas with tidal currents. The safest diving is during slack tide, which is the period when tides are about to change direction.

Diving In Currents

The direction and speed of currents are major factors to consider when planning your dive. Most dive plans require that you exit at or near your entry point. If you allow a current to carry you away from the boat, you may have to surface before you reach your exit location. This will require you to make a long surface swim against the current to make it back to your exit location.

The best approach to diving in a current is to begin your dive against the current. This allows you to turn around half-way through your dive, ride the current back to your exit location, and remain there until it's time to surface.

When strong currents are present, a rope should be extended behind the boat. This is called a current line, and is used to pull yourself against the current and back to the boat. If you are diving into the current, it is important that you always dive with a safety sausage so that even you are far away from the boat, the boat is still able to locate when you surface from the dive. It is also advisable to have an audible devise while diving so that you are able to get attention when you surface.

Current In Boracay Island

The usual question I usually received when divers asked about diving in Boracay; what are the currents situation in Boracay? Can I dive in Yapak now? Can I do a Channel Drift now? Diving in Boracay is relatively easy but there are few dive sites that we need to consider the current of the day. If we plan to dive in Yapak or Crocodile Island, it is important that we dive when tides are going up. 

Yapak that is situated at the Northern part of the island, the current will move in clockwise direction and as you descend, you will be swimming towards Yapak. In Crocodile Island that is situated at the Southern part of the island, the current will move in counter clockwise direction and you will be swimming towards Crocodile Island.

However; if you are planning to dive in Channel Drift or Santos, do make sure that the tides are going down when you dived in these sites. When tides are going down, the northern part of the island is going counter-clockwise and the southern part of the island will be going clockwise direction. Diving in Santos during low tide will bring you towards Balinghai, the southern west of the island. 

When you want to dive in Channel Drift, you will get into the water perpendicular to Crocodile Island and as you descent you will be swimming towards the southern west of the island. Remember diving in these sites, for the sake of safety, you are required to dive with a visible & audible devise. If you are drifted too far away, these devises will assist you to get attention from the boat.