Heavy Weather

Introduction

One's skill in boating can be truly tested when traversing heavy seas in bad weather. First of all, you should not be in a position where your boating skills are truly tested, assuming you properly pre-planned the trip and checked the weather forecast and water conditions. However, the sea can be unpredictable, and hopefully the comments below will be of use to you.

Different boats are designed for different water conditions. For example, one is either brave or insane, should a 12 ft tinny venture out onto Backstairs Passage off Kangaroo Island in 17-22 knt winds. With the added currents and tidal swells in this area, this spells disaster. I would even think twice about taking out a 16 ft half cabin in these conditions.

Perceptions of heavy weather varies from person to person. What one inexperienced boater may percieve to be rough seas, an experienced boater would construe as a comfortable challenge in navigation over water. Also visually misreading weather and water conditions can be detrimental to your health.

Swells and wave actions in larger bodies of water tend to build up more slowly as opposed to shallower waters usually found towards shore, which can produce breaking waves. I have actually found the reverse when traversing Backstairs Passage. One time, we could only manage about 8 knots heading back to Cape Jervis from Emu Bay thru the Passage. Once we hit those waters that were protected by the Cape, we were able to open the boat up to about 32 knots.

Know Your Boat

Have you ever driven a new car, and the initial feeling of its power, steerage and handling felt foreign to you ? The same feeling can apply to boats. It takes time to know your boat. No two boats are the same. Hull design, engine power, manouverability and stability are all facets in a boat that determine how well it will perform in calm and adverse sea conditions.

Simple concepts such as listenning to the tone of your engine during idle and high speed runs, can determine if your motor is running at optimum efficiency. Flatter hulls tend to bounce and skip a boat over the waves as opposed to deep V hulls which can cut thru the waves. Taking all these performance issues into hand, and knowing your boats limitations, will help you in comfortably navigating your boat in trying times of bad weather.

Meeting Head Seas

If heading into moderate seas, slowing the boat's speed will allow you to ride the waves thru, rather than trying to punch your hull thru the waves. Driving your boat thru the waves increases the level of impact of water against your hull, making it more susceptible to damage. It can also be a most uncomfortable ride for the occupants. I have had first hand experience of being intimate with the cabin's ceiling for 2 seconds during one such outing of heavy seas ! I was also christenned with a new crown on my head !

Most of the time, you may be able to traverse the waves at a constant but reduced speed. However, infrequent large waves may and do occur. Reading the waves as they are coming to you is a must. Should a large wave come towards your bow, throttle back on the power to reduce your speed and ride the wave. Then return to your original speed as you are riding the back of the wave.

Running in the Trough

Extra vigilance must be taken should you find yourself travelling in the trough of the waves or parrallel to the waves. The impact of the waves against your boat can cause the boat to roll excessively, and possibly to a point of capsize.

The best way to conteract this, is to use the analogy of sailboats tacking in a zig-zag fashion to reach their destination. You must do the same, where you try and minimise the amount of time that the boat must spend in the trough, and that the boat is only partially broadside to the swell.

Running Before the Sea

One of the tricks in running with the waves is timing. The concept is similiar to body surfing. You need to judge and maintain a certain speed as the wave reaches you, then adjust your power to match the velocity of the wave. During this manouver, your boat's stern can be swept from side to side, so ensuring that the boat stays perpendicular to the oncoming wave is a job in its own right.

Another point to ponder on is should you surf a too big a wave, the stern of the boat may lift out of the water exposing the rudder and prop, rendering them useless. The other end of the spectrum to this is the bow of the boat burrowing itself into the trough of the wave, creating a potential for a somersault.

Tacking the boat in a zig-zag fashion with the waves will negate or minimise any of the above effects. Another alternative would be to deploy a drogue, creating a drag, to reduce the onset of speed as the wave carries you forward.

Heaving To

Better to be safe than sorry ! If sea conditions are so severe that you deem it impossible to make headway, then heave to ! Look for a sheltered bay and ride the storm out. If that's not possible, turn the boat into the wind and provide just enough power to make steerage. This will ensure you don't drift around too much.