What do you know about Waves?
As you have probably guessed I often get asked a lot of questions about safety onboard and one that’s come up recently is how do waves impact on safety.
Obviously, they can and do have a major impact on vessel operations and safety but before we get into that it’s good to have some background.
Waves transmit energy passing through the water causing it to move in a circular motion. However, water does not actually travel in waves. Waves transmit energy, not water, across the ocean and if not obstructed by anything they have the potential to travel across an entire ocean basin.
Waves are most commonly caused by wind. Wind-driven waves or surface waves are created by friction between wind and surface water. As wind blows across the surface of the ocean or a lake, the continual disturbance creates a wave crest. These types of waves are found globally across the open ocean and along the coast.
More potentially hazardous waves can be caused by severe weather, like a cyclone. The strong winds and pressure from this type of severe storm causes storm surge, a series of long waves that are created far from shore in deeper water and intensify as they move closer to land.
Other hazardous waves can be caused by underwater disturbances that displace large amounts of water quickly such as earthquakes, landslides, or volcanic eruptions. These very long waves are called tsunamis.
Storm surge and tsunamis are not the types of waves you imagine crashing down on the shore. These waves roll upon the shore like a massive sea level rise and can reach far distances inland.
The gravitational pull of the sun and moon on the earth also causes waves. These waves are tides or, in other words, tidal waves. It is a common misconception that a tidal wave is also a tsunami. The cause of tsunamis is not related to tide information at all but can occur in any tidal state.
Anyone who has been to sea, especially in rough weather should understand the potential dangers associated with waves and wave action.
Waves dramatically impact on the way a vessel handles, its stability and in many cases its operations. Wave motion can cause free surface affect in fuel and water tanks which can cause major stability issues.
When crossing coastal bars waves can cause major issues including the loss of vessel, serious injury and loss of life!
A wave breaking on the deck where the water is unable to drain from the deck due to the volume of water or inadequate scuppers puts the vessel into a potential capsize situation.
Wave heights vary in height and as a guide I’ve included the following chart provided by the Bureau of Meteorology. This provides some really good information that you should take into account.
Don’t do what so many people do and that is take the ocean for granted, my number one recommendation is to treat it with respect at all times!
Number 2 is to ensure your vessel is prepared for unexpected waves at all times by keeping sea doors and hatches closed, cargo, product and other items are appropriately secured, and fuel and water tanks pressed to ensure appropriate stability when at sea.
While having the vessel prepared is good but…how are your crew. Are they prepared?
My tip is to ensure all crew are prepared for the voyage including knowing how to deal with waves and wave action including the use of safety equipment!