Ballasting A Boat: Tips For Success

Ballast is a weight placed in boats to increase stability and prevent them from tipping over or capsizing. It is typically placed in the lowest point of the boat, in a ballast tank, and can be made from a variety of materials, including lead, iron, cement, or water. The ballast will be kept below the water level to counteract the effects of weight above the water level. This guide will cover the basics of ballast, including the different types, how to fill ballast tanks, and the advantages and disadvantages of ballast systems.

Where to place ballast in a boat

When placing ballast in a boat, it is important to consider the type of boat and the activity it is being used for. The ballast should be placed in the lowest point of the boat, typically in the bilge, where it will have the most effect on the boat's stability. The basic principle is that the ballast will be kept below the water level to counteract the effects of weight above the water level.

For small sailing vessels, the simplest form of ballast is "live ballast", or the weight of the crew. On racing boats, a trapeze can be used to allow the crew to hang over the side of the hull, providing a larger righting moment due to the increased leverage of the crew's weight.

On larger modern vessels, the keel is often made of or filled with a high-density material, such as concrete, iron, or lead. By placing the weight as low as possible, often in a large bulb at the bottom of the keel, the maximum righting moment can be achieved. Traditional forms of ballast carried inside the hull include stones or sand.

Water ballast systems are commonly used in sailboats, with internal tanks that can be filled or emptied depending on the direction of travel (upwind or downwind). These tanks are usually located near the hull and may have switches for maintaining the water level.

For boats used for wakeboarding and wakesurfing, the placement of ballast will depend on the desired shape of the wake. Weight in the rear of the boat will result in a more vertical wake, while moving more weight towards the bow will create a more mellow wake. For wakeboarding, it is recommended to have an even weight distribution throughout the hull, while wakesurfing requires more weight in the rear of the boat to create a wake with enough "push" or energy.

How much ballast to put in a boat

The amount of ballast you put in a boat depends on several factors, including the size of the boat, desired wake size, space requirements, comfort level, and activity.

Firstly, ballast is used to provide stability to a boat by lowering its centre of gravity. This is particularly important for boats travelling in high winds, as insufficient ballast can cause the boat to tip or heel excessively, and even capsize. Therefore, the amount of ballast you put in your boat will depend on the weather conditions you are expecting to encounter.

Secondly, the ballast you add will depend on the size of your boat. Larger boats will require more ballast to stabilise them, but they will also have more space to store ballast. When considering how much ballast to add, you must also think about how much room you are willing to give up in the boat for ballast.

Thirdly, the amount of ballast will depend on the desired wake size. If you are looking to create a bigger wake for wakeboarding or wakesurfing, you will need to add more ballast to your boat, which will cause the hull to displace more water as it moves through it.

If you are primarily concerned with creating a bigger wake, it is recommended to distribute ballast evenly throughout the hull of the boat. This will ensure the boat remains stable and provide a clean wake. However, if you are looking to alter the shape of the wake, you can adjust the distribution of ballast. For example, adding more weight to the rear of the boat will result in a more vertical wake, while moving weight towards the bow will create a more mellow wake.

Finally, the amount of ballast you put in your boat must also take into account comfort and safety. Overloading a boat with too much ballast can be dangerous and may result in the boat ending up on the bottom of the lake. Always refer to the capacity ratings provided by the National Marine Manufacturers Association (NMMA) to ensure you do not exceed the safe amount of weight for your boat. These ratings take into account factors such as boat size, depth, materials, and flotation to determine a safe weight limit.

Types of ballast

The ballast you choose for your boat depends on its size and weight, your riding style and preferences, and the type of water activities you plan to engage in. Here are some of the most common types of ballast:

Water Ballast

Water ballast is commonly used in small boats as it is easy to adjust and does not add excessive weight to the vessel. Water is pumped into ballast bags or tanks, increasing the overall weight of the boat and displacing more water, which creates a bigger wake. Water ballast is also used on empty cargo vessels to improve steering and control the trim and draft. However, one disadvantage is that water is not very dense, so water ballast requires more space than other forms of ballast.

Weighted Ballast

Weighted ballast can take the form of ballast bags, which are heavy-duty malleable containers that can be filled with water or other materials such as steel shot. These bags can be placed in different areas of the boat to adjust the distribution of weight and achieve the desired wake shape and size. Weighted ballast can also take the form of high-density material, such as concrete, iron, or lead, placed in the keel of larger vessels. While this provides greater stability, it also increases the mass of the boat, which can impact its responsiveness and manoeuvrability.

Live Ballast

Live ballast refers to the weight of the crew in small sailing vessels. By sitting on the windward side of the hull, the crew's weight creates a righting moment that helps to stabilise the boat. On racing boats, a trapeze (a wire harness) is sometimes used to allow the crew to hang over the side of the hull for greater stability, although this can be dangerous if the wind suddenly dies.

How to fill a ballast tank

Filling a ballast tank is a crucial step in ensuring the stability of your boat. Here is a comprehensive guide on how to fill a ballast tank:

Locating the Ballast Tank

First, you need to locate the ballast tank in your boat. It is usually found near the boat's hull, sitting lower, closer to the waterline. The ballast tank is part of a water ballast system, which includes pumps and tanks.

Understanding the Direction of Travel

The process of filling and emptying the ballast tank depends on whether you are travelling upwind or downwind. When sailing upwind, ensure the ballast tanks are full, and when sailing downwind, keep them mostly empty.

Filling the Ballast Tank

Now, let's get into the step-by-step process of filling the ballast tank:

• If your boat has switches for maintaining ballast tank fullness, turn on the switch to start filling the tank.
• Monitor the water level in the tank. Some tanks have automatic shut-off mechanisms when they are full, but if yours doesn't, be sure to turn off the switch manually when the water reaches the top of the tank.
• To fill the tank, use the ballast pump that comes equipped with your sailboat. This pump transfers water to the tank so you don't have to do it manually.
• If your boat uses ballast bags instead of or in addition to tanks, lay the bag on a flat surface. Attach the fill connection to the fill port, usually found at the top of the ballast bag.
• Tighten both sides of the tube, and then place the ballast pump into the water, ensuring it is deep enough so that it doesn't float.
• Connect the extension cord from the ballast pump to your boat's cigarette adapter to power the pump. Alternatively, you can fill the ballast bags in your car before heading out onto the water.
• Check for excess air in the ballast bag, as this will cause water to come with it when filling.

Releasing Air from the Ballast Bags

To release air from the ballast bags, connect your ballast pump to the included field drain. Position the hose so that the water drains out of the boat rather than into it.

Using Valved Pipes

If your boat has valved pipes connecting the starboard and port tanks, you can use them to your advantage. Open the valve to allow water to pass from the windward or upward tank to the leeward or downward side. This helps control the sailboat's heel and improves its stability.

Remember, the amount of ballast you need depends on factors such as displacement, hull design, and boat type. Always refer to your owner's manual for specific instructions and safety precautions related to your boat's ballast system.

Pros and cons of ballast systems

Ballast is a dense material used as a weight to provide stability to boats. It is placed in the boat to lower its centre of gravity, increasing stability and preventing the boat from tipping or heeling excessively in high winds.

There are several pros and cons to ballast systems.

Pros

• Stability: Ballast systems provide stability to boats, especially in high winds, preventing them from tipping over or capsizing.
• Speed: By reducing the heel angle, ballast systems can help maintain the sails, rudder, and keel in a horizontal position, reducing downward sail pressure and increasing the speed of the boat.
• Control: Ballast systems allow for better control of the boat by providing more handling of the draft, trim, and steering.
• Weight adjustment: The weight of the boat can be adjusted on-the-go by managing the water ballast tanks, which can be easily filled or drained of water.
• Space-saving: In some boats, ballast bags are used instead of tanks, which can be installed near the hull and outboard, saving space.

Cons

• Bulky and heavy: Ballast tanks can be bulky and heavy, taking up valuable space in the boat.
• Environmental concerns: Filling and draining ballast tanks in different bodies of water can release foreign microorganisms, viruses, small animals, and plants, potentially harming the ecosystem. This is a significant issue for large boats like cargo carriers, tankers, and cruise ships.
• Maintenance: Ballast systems require regular maintenance to prevent issues such as filter choking, system breakdowns, and overheating of sensors and circuits.
• Cost: The components of ballast systems, such as pumps and tanks, can be costly, and the replacement parts may be expensive as well.
• Time-consuming: Filling and draining ballast tanks can be time-consuming, especially if done manually.
• Performance: While ballast systems improve stability, they can also increase the mass of the boat, leading to decreased responsiveness to steering and reduced speed due to increased drag.

Frequently asked questions