Category: Equipment: theory and practice

Authors of the photos: OCEAN, DAN-FENDER

Mooring fenders, commonly referred to as bumpers, are indispensable in protecting a vessel’s hull during docking. They absorb the force of impact when a ship comes into contact with a pier or another vessel, particularly during towing operations. Typically made from PVC material, these fenders are placed along the sides of the ship just before docking, serving as a buffer to absorb collision energy. For example, Ocean uses Plastisol PVC material to produce all of its fenders, which is highly valued for its properties, including:

• Chemical Resistance: It remains inert when exposed to a wide range of chemicals and petroleum products.

• Elasticity: The material’s flexibility allows it to absorb substantial impact without damage.

• Energy Dissipation: Fenders are designed to absorb and distribute the energy from collisions effectively.

• Mechanical Strength: They resist deformation even under heavy loads.

• Environmental Durability: These fenders can withstand harsh environmental conditions, such as extreme temperatures, UV radiation, and prolonged exposure to seawater.

Choosing the Right Mooring Fenders

Selecting the appropriate mooring fenders depends largely on the design of the vessel and specific mooring conditions. Though there are no rigid rules, here are some general recommendations:

• Use one fender for every 2.5 meters of the vessel’s length, with at least three fenders per side.

• Most vessels should have between 6 to 8 fenders.

• To determine the appropriate fender diameter, apply the formula: 2.5 cm per 1.2 meters of vessel length. For instance, a 30-foot boat would require a fender with a diameter of around 20.8 cm.

• The fender’s length should be approximately two-thirds of the vessel’s freeboard height.

• For inflatable fenders, maintain a pressure of 0.15-0.2 atmospheres (kg/cm²), and check the pressure once or twice a year.

Understanding the Categories of Mooring Fenders

Mooring fenders are categorized by their application and their position on the vessel.

Application-Based Categories:

1. Temporary Fenders: These are used on standard vessels, attached just before docking and removed afterward.

2. Permanent Fenders: Typically found on icebreakers and tugboats, these fenders are permanently installed for continuous protection.

Positioning-Based Categories:

1. Floating Fenders: These buoy-like fenders are connected by rigging chains and float on the water’s surface, making them ideal for larger vessels due to their bulk and weight.

2. Handing Fenders: Also known as bow, side and stern fenders, these are used on smaller vessels. They can be raised or lowered easily, without the need for winches or pulleys, and are suspended along the vessel’s sides using ropes or chains during docking.

Types of Hanging Fenders:

• Bow Fenders: These are hollow, rubber cylinders shaped like a boomerang, permanently installed at the bow to protect this vulnerable part of the vessel.

 

Example – OCEAN Bow Fenders

• Cylindrical Side Fenders: Installed on both sides of the ship, these fenders can be adjusted in height or removed as needed.

Example – OCEAN Fenders H SERIES, OCEAN Fenders U SERIES, OCEAN Fenders CH SERIES, OCEAN Fenders RT SERIES, 

OCEAN  Mega Yacht Fenders MAGNUS SERIES, OCEAN  Mega Yacht Fenders EASYSTORES PLUS SERIES

• Round stern or side fenders: These are installed on the stern or swim platform and can also be mounted along the sides, closer to the bow of the vessel. These fenders can be adjusted in height and removed as needed. They provide protection during stern-to-dock mooring.

Example – OCEAN Buoys R SERIES

Operational Considerations for Using Mooring Fenders

When it comes to using inflatable fenders, they can be inflated with a standard car pump or compressor. However, it’s important to monitor the pressure, as the air inside the fender can expand under direct sunlight, potentially increasing internal pressure.

Fenders should be deployed just before the vessel enters the marina, alongside other docking preparations such as securing mooring lines and preparing to drop anchor.

On smaller vessels, fenders are usually attached to the sides using mooring cleats. For those with less experience, there is a risk of entangling the fender lines with the mooring lines during docking. To prevent this, it may be beneficial to install special hooks or clips along the sides or superstructure, which can help in the quick and efficient deployment or removal of fenders.

The “figure-eight” or “clove hitch” knots are highly recommended for securing fender lines due to their ease of tying and reliability.

Energy Absorption and Distribution in Mooring Fenders

Mooring fenders are also classified based on how they absorb and distribute impact energy:

1. Shock-Absorbing Fenders: These include elastic, pneumatic (air-filled) fenders that are designed to absorb the energy from impacts.

2. Damping Fenders: Available in gas or hydraulic variants, these fenders dissipate impact energy by compressing the gas or liquid inside.

3. Combined Fenders: Hydro-elastic and hydro-pneumatic fenders combine the features of shock-absorbing and damping fenders, offering enhanced protection through a dual-shell design.

Types of Shock-Absorbing Fenders

Pneumatic fenders come in two main designs: chambered and non-chambered.

• Non-Chambered Fenders: These consist of a single rubber shell reinforced with metal or polymer cords. These fenders are mainly used for pleasure motor yachts and sailboats up to 60 feet in size.

• Chambered Fenders: Also known as double-layer fenders, these feature an outer shell made of rubber-cord material and an inner sealing shell. These fenders are very often used for larger yachts and mega yachts.

Types of Damping Fenders

Hydraulic damping fenders are made from thick, durable rubber with holes that allow water to escape when compressed, effectively absorbing impact energy. These fenders are typically hung vertically and can be adjusted for positive or negative buoyancy. Gas damping fenders, on the other hand, use compressed air or gas to dissipate energy during impacts.

Combined Fenders

Hydro-elastic and hydro-pneumatic fenders incorporate air and water to absorb impact energy. The inner shell is filled with air, while the space between the shells contains water that is displaced upon impact. This design makes them compact and suitable for a range of vessel sizes.

Modern Mooring Fenders

Modern OCEAN fenders are equipped with two D-rings on opposite ends, allowing them to be mounted either vertically with one ring or horizontally using both rings, depending on the docking scenario.

A life jacket is one of the most important pieces of equipment for water sports enthusiasts. A properly selected life jacket ensures safety and comfort. Let’s see how to choose the right model, considering the specifics of various water sports.

Key Characteristics of Life Jackets

Type of Jacket: Life jackets are divided into three main types: foam, inflatable (automatic and manual), and hybrid.

Buoyancy: This parameter determines the jacket’s ability to keep a person afloat. The higher the buoyancy value, the better the jacket performs its task.

Size and Adjustability: Choosing the right size and the ability to adjust the jacket ensure comfortable and safe use.

Materials: Jackets can be made from various materials affecting their durability, longevity, and ease of use.

Choosing a Life Jacket for Different Water Sports

Rowing and Kayaking

When selecting a life jacket for rowing sports, consider the following features:

• A jacket with a short back and ample shoulder movement.
• Pockets and attachments for accessories.
• Thin foam material for better comfort and reduced weight.

An excellent choice for rowing sports is the Lalizas Buoyancy Aid, Performance 50N.

Wakeboarding and Kitesurfing

For wakeboarding and kitesurfing, the recommendations are:

• Rigid and impact-resistant material on the chest and back for extra protection during falls.
• Multiple adjustment options for a snug and secure fit.
• Quick-drying materials.

Check out the Lalizas Buoyancy Aid, Neo 50N and Fit & Float Buoyancy Aid, 50N, ideal for wakeboarding and kitesurfing.

Sailing

For sailing, suitable life jackets should have the following characteristics:

• Waterproof materials.
• Reflective elements for better visibility on the water and at night.
• Extra pockets and attachments for tools and accessories.

Consider the Lalizas Buoyancy Aid, Easy Rider 50N available at Gaelix Marine Service.

Rafting and Water Tourism

When choosing a life jacket for rafting and water tourism, pay attention to:

• High buoyancy for better safety in fast currents and rapids.
• Impact-resistant materials for protection against rocks and obstacles.
• Loops and attachments for a rescue rope and auxiliary equipment.

Ideal for rafting are the Lalizas Buoyancy Aid Pro Race, 50N and Lalizas Buoyancy Aid, Slalom 50N.

Motorboats and Yachts

For safe boating and yachting, the following models are suitable:

• Automatic or manual inflatable jackets for high buoyancy.
• Jackets with convenient and durable fastenings for secure use at speed.
• Jackets with an integrated whistle to attract attention in case of an emergency.

The lightest and safest inflatable jackets from Lalizas include: Lalizas Kappa, Lalizas Theta, Lalizas Sigma, Lalizas Alpha, Lalizas Zeta, and Lalizas Omega.

Tips for Care and Storage of a Life Jacket

1. After use, wipe the jacket thoroughly and dry it in the open air, avoiding direct sunlight.
2. Store the jacket in a dry and ventilated place.
3. Regularly check the condition of the jacket for wear, damage, and the reliability of seams and fastenings.

A properly selected life jacket, considering the specifics of various water sports and recreational activities, will significantly enhance safety and comfort. Take the time to choose reliable and high-quality equipment to enjoy water adventures without fear and risk to your health.

Buy Lalizas life jackets at the best prices at Gaelix Marine Service.

Authors of the photos: Graham Snook/Yachting Monthly, Panmaule, Lalizas Today, let’s talk about liferafts. When outfitting a yacht, sooner or later, you will need to choose a liferaft as the last resort in case of an emergency. Therefore, it’s important not only to choose the brand but also to understand what exactly you are buying. Key Differences in Liferafts The main differences in liferafts lie in their configuration and their ability to right themselves, which is why rafts are divided into regular and self-righting. This is a crucial feature. When a raft is dropped into the water, it should set itself up properly. Similarly, if a self-righting raft is flipped by a wave, it is easier to restore to its normal position. All rafts for non-commercial vessels are manufactured according to ISO-9650 standards. There are differences in the quality of materials and components, but all of them are certified. Some manufacturers obtain additional certifications from ISAF, RORC, etc., but essentially, they are all similar. Main Differences in Configuration The main difference lies in the configuration, i.e., what is inside the raft. There are three groups for recreational vessels: -24 hours, +24 hours, and SOLAS-B configuration. The first differs from the second by adding a Grab Bag, an additional bag of supplies that is loaded into the raft separately. It is assumed that the crew for whom the raft is designed will be on the raft for less than 24 hours or more, which slightly changes the configuration of the raft: -24 Hour Pack Handheld red flare x 3 Parachute rockets x 2 Seasickness tablets x 60 Signal torch x 1 Thermal protective aid (TPA) x 2 Repair kit x 1 Whistle x 1 Signal mirror x 1 Oar x 2 Water supply: 1/2 liter per person Bail bucket x 1 Sponge x 2 Hand pump x 1 Paper bags x 10 +24 Hour Pack Handheld red flare x 3 Parachute rockets x 2 Seasickness tablets x 60 Signal torch x 1 Thermal protection x 2 Repair kit x 1 Whistle x 1 Signal mirror x 1 Oar x 2 Water supply: 1/2 liter per person Bail bucket x 1 Sponge x 2 Hand pump x 1 Paper bags x 10 Grab Bag 2 x Thermal Protective Aids 1 liter of water per person 1/2 kg of food rations per person 3 x red flares 1 x first aid kit SOLAS B Pack Red flare x 3 Orange smoke signal x 1 Parachute rocket x 2 Category C first aid kit x 1 Seasickness tablets x 60 Signal torch x 1 Repair kit x 1 Whistle x 1 Radar reflector x 1 Oar x 2 Signal mirror x 1 Bail bucket x 1 Sponge x 2 Hand pump x 1 Paper bags x 10 Thermal protection x 2 Sea anchor x 1 Instructions x 1 Cost and Quality Considerations There are many manufacturers, and prices vary significantly. The same raft can cost from 800 to 2000 euros. One of the leaders in terms of quality and price is the Greek company Lalizas, although its products are primarily used by commercial vessels. Lalizas also equips pilot and coast guard vessels with its rescue equipment. Additionally, it is one of the few manufacturers that produce liferafts in Greece, so there is no doubt about the reliability of its products. The most well-known brands of liferafts for recreational or charter boats and yachts are LALIZAS ISO ATLANTIC and LALIZAS SEAWORLD. You can purchase Lalizas liferafts of any model and in any quantity at wholesale prices from the Gaelix Marine Service online store. Packaging Type and Storage Method Another characteristic of a liferaft to consider when purchasing is the type of packaging and storage method. Liferafts can come packed in a plastic container or in a soft valise. The choice depends on your boat and whether there is space to install a container or if it is more convenient to store a valise. Both types of packaging have their advantages and disadvantages. Usually, the container is installed permanently in a special stainless steel bracket on the stern or on the cabin roof. It is assumed that the raft will be dropped overboard from this bracket, and if a hydrostatic release is installed, the raft should float to the surface if the yacht sinks. However, while this is clear for the stern, throwing a raft weighing about 40 kg in a slippery plastic container from the bow deck, especially in waves and for an exhausted person, is not an easy task. A liferaft in a bag is certainly lighter. It can be stored in a cockpit locker or a special stern locker. It is easier to carry to the leeward side or another convenient place, but launching it will take a bit more time than throwing a liferaft from a stern bracket. Lifespan and Servicing Another important parameter of a liferaft is its guaranteed storage period, which usually ranges from 3 to 6 years depending on the manufacturer. Before the expiration date, the liferaft must be taken to a service company, which will repackage the raft, replace the air cylinder, pyrotechnics, and supplies. This operation usually costs around 300-500 euros and takes a few days. Why Timely Repackaging is Important It’s crucial to perform timely repackaging because if you ever need to use the liferaft, it might be a one-time necessity. If the raft fails to inflate, there’s no point in having carried it for years. Therefore, if you have a liferaft on board, it must always be in working condition. This also applies to automatic inflatable life jackets, which are very popular among yachtsmen, but that’s a topic for another time. I hope you never need to use your liferaft.

A clear and concise analysis of various types of yacht hulls.

 

The behavior of a yacht on water and its usability depend directly on the type of hull. When choosing a yacht, it’s essential to determine which hull type suits your specific needs. In this article, we’ll list the main types of hulls existing today and clearly illustrate their differences.

Two main types of hulls using the example of a knife and a box.
The development and improvement of hulls aim to reduce the hull’s resistance when moving through the water. All hulls experience wave resistance, overcome frictional force, as well as resistance from form, aerodynamics, induction, and spray. Each design copes with these forces differently. Let’s consider how different designs behave in water using the example of a knife and a box. Imagine placing them in a pool as if they were two boats. The knife easily cuts through the water, even in waves. However, it doesn’t float, and its size doesn’t allow anything to be loaded onto it. In contrast, the box behaves differently: it floats well, even with a load, but it rocks on waves, especially when stationary, and in motion, such a hull will be hit by each wave with its full width.

Of course, this is a very rough comparison, but it accurately describes the behavior of the hull in water depending on its shape and the tasks faced by yacht designers. It’s intuitive that for faster speeds, a narrow hull that easily cuts through the water and creates minimal resistance is needed, but for comfortable accommodation of a large number of people, something box-like resembling a barge would be suitable.

The key is to combine the advantages of the “knife” and the “box” in one hull.

The more the hull’s shape resembles a “knife,” the faster the yacht, and the more it resembles a “box,” the more spacious and comfortable it is. Roughly speaking, a “knife” is a planing hull, and a “box” is a displacement hull. These are the two poles in yacht design. Between them, there are transitional types of hulls, and within them, there are subtypes depending on the shape of the bottom and the lines of the sides.

Advantages and Disadvantages of Displacement Hulls
Remember the school rhyme to remember Archimedes’ law, which allows bodies not to sink in water? “A body immersed in water displaces a volume equal to the volume of the body, with a force equal to the force of the displaced water.” In the case of displacement boats, Archimedes’ force is the main force acting on the yacht. Balanced Archimedes’ force and the force of gravity suspend the hull in the water, much like a buoy. So when moving, it simply pushes through the water due to the momentum received from the propeller or sails.

To make it easier for a yacht to push through the water, the shape of the hull below the waterline is often made round, smooth – to minimize water friction. They resemble ideally polished sea pebbles through which water passes without stopping. Only the yacht’s bow is made sharp to cut through the water like a knife, without raising a large wave. Even if the hull’s construction occasionally involves sharp edges (when the contours resemble a faceted glass), they are directed so that they intersect the waterline at the bluntest angle possible or don’t intersect it at all. After all, any extra angles and recesses create unwanted whirlpools, which slow down the boat.

The biggest limitation of yachts with displacement hulls is their speed. The formula for calculating the maximum speed of a displacement hull would look like this:

Here,

Lwl represents the length of the vessel at the waterline in feet.

Vmax represents the maximum speed of the vessel in knots.

Simply put, the speed of a displacement hull is limited by its length.

 

Of course, installing an extremely powerful engine can make the yacht go faster, but most of the “extra power” will be used to overcome resistance, as the hull is not designed for high speeds and will start “plowing” through the water, pushing a waves ahead of it.

As the speed increases linearly, the required power increases cubically. For example, to double the speed of a displacement yacht, the engine power needs to be increased by eight times. And to triple the speed, the power must be increased by 27 times.

To reduce wave resistance, a bow fairing of the boat is pear-shaped form is applied. It is positioned below the waterline and forms its own wave system, which overlays the hull’s wave system and reduces its impact.

Displacement boats significantly lag behind planing boats in speed when comparing vessels of the same size.

BUT HERE LIES THE GREAT ADVANTAGE OF DISPLACEMENT YACHTS: THEY ARE MUCH MORE FUEL-EFFICIENT AND PROVIDE GREATER COMFORT FOR EMBARKING ON LONG CRUISES AND NAVIGATING LONG DISTANCES.

The low speeds of displacement hulls significantly reduce the skipper’s ability to avoid an approaching storm or escape from a thunderstorm. At low speeds, it’s more challenging to navigate through heavy seas. Additionally, you won’t be able to maneuver between waves, which could significantly enhance safety and facilitate transitioning in bad weather conditions.

Displacement hulls also face the challenge of typically having a deeper draft compared to planing hulls, which restricts their maneuverability in shallow waters.

WHILE PLANING YACHTS MIGHT THEORETICALLY EVADE ADVERSE WEATHER CONDITIONS, IN THE EVENT OF A STORM, YOU’D PREFER TO BE ABOARD A YACHT WITH A DISPLACEMENT HULL.

For longitudinal stability on waves, which rock the boat sideways, the correct ratio of hull length to width is required. For example, for boats ranging from 6 to 12 meters in length, the hull length should be 3.5–4.75 times greater than its width. A displacement yacht sails steadily on the water, without a heel to the stern (longitudinal inclination of the hull to the corresponding side), allowing travel to continue even in bad weather.

SUCH YACHTS DO NOT FEAR EITHER ROLL OR PITCH, WHERE THE BOAT LIFTS BOTH THE BOW OR THE STERN.

To maintain the boat in a normal position, it is not necessary to apply much additional effort. There can be a lot of cargo on board (including passengers), and it can be distributed relatively freely across the yacht. Although the occurrence of heel (sideways tilt) or sternward heel is undesirable, even in this case the vessel will be able to continue moving. The weight of the boat itself also plays a minor role. With planing yachts, things are different.