Caught out in Rough Weather
Not every boatie wants to mix it with rough water or go out in heavy weather. However, there are times when it may be necessary
HEAVY WEATHER AND ROUGH WATER HANDLING.
Not every boatie wants to mix it with rough water or go out in heavy weather. However, there are times when it may be necessary. Serious offshore fishermen accept the fact that at times to get to your favourite spot, crossing a bar and dealing with rough water is part of the game. Those less experienced or who wish to fish in sheltered waters may have to cope with rough water from time to time. It shouldn’t be a terrifying experience. Sure you can be frightened and you do need to respect the sea and the weather, but dealing with rough water situations is a basic safety skill that every boatie should have..
Take some of our large semi enclosed waterways, Port Phillip, Botany Bay, Moreton Bay, the South Australian Gulf area and look at the reputation they have when it blows up. And it can blow up suddenly on these waters. Even the large inland waters like Eucumbene, Lake Eildon, Lake Macquarie etc. can chop up quite severely and quite quickly.
With a little practical experience and knowledge of how you handle rough waters, confidence in your ability to handle the rough water situation will grow. This will make your boating safer and more pleasant.
What Is The Influencing Factor Making Normally Calm Water Rough?
Inshore and Inland Waters.
Wind is by far the most significant influencing factor in whether you are going to get a smooth or rough day. The wind will start rippling the water and gradually create waves. If the wind continues to remain constant in strength waves roll along and may tend to get larger. Wind produced waves are usually called chop. Other factors affecting waves on inshore waters will be tide and to and extend the underwater topography. If there is a tidal flow or current in one direction and a wind blowing and making waves from an opposite direction, the waves will tend to stand up as the two forces meet. These types of waves can be quite powerful, uncomfortable and dangerous.
The underwater profile of the sea bed can influence how waves form. If the area is a constant depth waves tend to be fairly uniform as there is little push up providing resistance to the moving water. As seabeds shelve, that is get shallower, the water dragging along the seabed slows down if relation to that on top. This causes the waves to break, usually on shorelines but if shallow banks exist offshore, sudden breaking of a wave can occur offshore.
Waves or chop breaking onshore in confined waters have to go somewhere and it always rolls back in the water this can cause added chop with waves going in different directions. This is called a confused sea.
The distance a wind has to blow across a piece of water is called “fetch” The greater distance or fetch there is, the more likely the waves will be larger. They will start off small nearest the land fall from where the wind is blowing and get larger as you get further off that landfall.
In Inland waters, the surrounding country side can also be a significant factor in the formation of waves. Winds can be funnelled and squeezed through surrounding hills causing sudden sharp gusts sometimes called “Bullets” across the water.
Not only do you have wind and fetch and underwater topography the deal with in coastal waters, but swells have to be contended with. Swells are long heavy rises and falls of the waters surface and are usually caused by influences some distance away.
The same rules apply in offshore waters regarding wind over tide or current. It can cause disturbed waters with short sharp waves usually called rips. Added to these influences are the formation of wind waves on top of swells and in offshore situations you really need you wits about you.
Dealing with Rough Seas.
As with most things in boating, being it touch your environment and knowing your local area will go along way to helping you predict what the sea conditions are going to be.
Armed with a boating weather forecast and tidal or current information you are pretty well set to decide where the smoothest waters can be found.
But don’t just do the theory. Having a look at actual conditions and knowledge of local phenomena must be added to the decision making process. You should know what a Southerly Buster looks like coming up the Coast. Those in the West should be aware if conditions are such that the “doctor” will spring up in the afternoon and Victorian boaties must be aware of typical indicators of South West Fronts. Each area has it’s unique weather indicators and knowing them can help you avoid trip through rough water.
What If You Do Get Caught Out?
Preparation is the key. Not everyone can or wants to get practical experience in rough water handling but you should at the very least be aware of how your boat handles in a strong wind and in a moderate chop. You don’t need to put yourself in danger to find this out. Consider some experience in a light to moderate chop accompanied by an experienced boatman. In calm waters under a lee, see how your boat behaves in a strong wind. This all helps build confidence for the real thing.
· Have those on board wear their PFD’s (Lifejackets) and make sure you don’t have people in enclosed cabins. PFD’s will not only keep you afloat in the water, but they can adsorb blows in a person is thrown around in the boat. Depending on the boat size it may be as legal requirement (Heightened Risk) to wear your PFD but it makes sense in any case.
· Make sure your boat is operating correctly. This should have been done before hitting the water. Steering and engine controls are vital.
· Stow loose articles securely so they don't fly about and become a danger to those on board. Don’t forget to check that the battery and anchor are secure.
· Brief your passengers and tell them to hold on.
· Switch to the fuel tank that has the most fuel left. This will save having to change later in rougher conditions.
· Electric Bilge turned pump on if fitted and able to be run continuously.
If you have radio fitted consider a call to the local volunteer marine rescue station giving your location and intentions.
Keeping your boat stable and reducing the risk of capsize is something you should always think about. In rough weather it is vital to re assess your stability factors. Keep weight low and evenly distributed and a low as possible. Keep the boat properly trimmed for the sea conditions (see later points) and remove any excess water in the boat.
Handling the Boat.
You will encounter three different sea types depending on the way you are travelling. Head seas are those when are going into the waves. Following Seas are if you are going in the same direction as the waves and a Beam Sea is when the waves are coming from either side.
In all seas, the proper use of power is important. Most likely in rough weather you will not be able to set the power and leave it. Power management will be essential. Generally your speed should be reduced in order to reduce stress on the boats hull.
Remember that fuel consumption may be higher as you work the throttle back and forward in response to the seas you encounter.
When motoring into a head sea, the boat should be trimmed bow down slightly. That is to say the bow should not be raised. If it is, you run the risk of launching the boat skyward up the face of a wave. Anything from an uncomfortable crash down the other side to flipping the boat is possible
The downward trim is a compromise, to much and you will bury the bow into the oncoming waves, to little and a light bow will not track truly through the sea.
Use the power lever to keep the bow controlled into the oncoming wave reducing the power as you rise over it, adding power again to keep the boat into the next oncoming wave. You can make a head sea ride more comfortable by quartering the wave. This technique involves meeting the waves at about a 10 - 15 degree off square on. It makes the ride over the wave more comfortable but can mean you ship more spray into the boat. It also means your course will be zig zagged therefore taking longer. This is called tacking.
Trim the boat bow up. This stops the bow burying itself into the next wave as you go over one wave and into the next. If possible get onto the back of a wave and stay there holding position. Keep a look out for any waves behind you that are travelling faster than you and that may break across the boat. These are rare but can occur in tidal waters and confused seas. If you have to power over the back to a wave be careful of broaching. This occurs where you lose steerage going down the face of a wave as the boat and wave are travelling at the same speed. When you reach the bottom, the boat is forced side on and may be rolled. Outboard motor boats are able to recover from broaching by the application of power. Be content to take you time in a following sea.
Although considered a dangerous practice, under certain conditions boats can be sailed along a beam sea quite safely. Generally where there is a constant steady pattern of waves with a reasonable distance between them, Beam Sea running may be achieved safely. Remember the danger lies in short sharp steep seas that tend to roll or swamp the boat.
Unless you are experienced and the vessel capable, beam sea running should be done with utmost caution. When done properly and by experienced persons, quite high speeds can be safely attained in beam seas.
Remember that fuel consumption will increase in heavy weather. Pushing into waves or powering on to keep up in a following sea will see you chew through fuel more quickly than when planing across calmer waters.
Your fuels calculations for each trip should take into account the possibility of encountering heavy weather and increases of around 30% in fuel usage is not uncommon
This article provides basic information about rough weather handling. There are quite a few good boating publications that cover rough weather handling in detail and usually can be obtained at good book stores and boating shops.
Remember that a lot can be learned from watching others and how they deal with rough weather. Consider going out with some one experienced to see what happens before you try.
By taking small steps by practicing in a light chop them building up, your confidence and skills in handling vessels in rough should develop to a level where you can safely and comfortably handle heavy weather situations thrown up to you.
Doug King – Boating Instructor – Boating Victoria
This article is general information only. It should not be viewed as operational instruction or as a substitute for formal training.