MOORINGS

WHAT IS A MOORING SYSTEM?

DOCK MOORING SYSTEMS

Dock mooring systems keep boats, floating platforms, and other watercraft stationary at all water depths. They can support watercraft of all shapes and sizes, including:

  • Cargo vessels
  • Cruise ships
  • Fishing boats
  • Kayaks
  • Personal watercraft (PWCs or jet skis)
  • Pontoon boats
  • Powerboats

There are two primary types of mooring systems: a shore fixture like a pier or an offshore fixture like a floating dock system.

SIX CATEGORIES OF DOCK MOORING SYSTEMS

Additionally, there are six categories of dock mooring systems. They are:

  • Catenary
  • Dynamic position
  • Semi-taut
  • Single point
  • Spread
  • Taut leg

CHOOSE YOUR DOCK MOORING

Regardless of the mooring system you choose, your dock mooring must be able to withstand a number of different forces, such as:

  • The current
  • The tide
  • Waves
  • Wind
  • Adverse weather conditions

REQUIRED COMPONENTS

For a mooring system to function correctly, it requires several key components.

MOORING ANCHOR

The mooring anchor keeps the watercraft steady in a fixed position while it is being moored.

Your mooring system relies heavily on the strength of its anchor. The holding capacity of each anchor depends on the water depth, seafloor soil properties, and type of anchor you use.

Experts suggest using a mooring anchor that is at least three times the weight of your service anchor. If you’re unsure about the size and weight of the anchor you need, it’s best to ask the dock mooring professionals at Haven Dock and Marine for advice.

MOORING CHAIN

The mooring chain is a line that connects the anchor to a floating buoy or watercraft.

Although chain is the most common type of mooring line, there are various mooring lines and ropes to choose from. Others include:

  • High modulus fibers
  • Synthetic fiber rope
  • Wire

Stick with chain for permanent moorings in waters up to 328 ft (100 m). For waters deeper than 984 ft (300 m), it’s better to choose a stainless steel wire rope.

For ultradeep waters (more than 6,560 ft or 2,000 m), you’ll want to use a combination line of chain, wire, and synthetic fiber for maximum strength.

Experts recommend that your mooring line is three times the length of the water’s depth and a quarter inch thicker than your service chain.

It’s also a good idea to invest in mooring line supports. These supports protect the line from chafing, especially with consistent use.

You may also consider getting mooring whips. Mooring whips look like giant fishing poles. They are solid fiberglass rods that keep your watercraft a safe distance away from the dock edge to prevent damage during unfavorable weather conditions.

MOORING BUOY

The mooring buoy floats in the water away from the shoreline. The buoy allows boats to be moored in deep water instead of shallow water or to a pier.

They are heavier than standard buoys to allow for mooring. Traditional buoys only act as locators or warning devices for ships.

5 BASIC TYPES OF ANCHORS

Boat dock mooring systems can use five different types of anchors. Read about them in-depth to see which is best for your mooring system.

DEADWEIGHT ANCHORS

Deadweight anchors use weight as their holding power and are the simplest type of anchor. The weight will settle at the bottom of the sea (or lake) floor and become embedded. Then, the suction effect will increase the anchor’s holding power.

While you can use any heavy-weight object as a deadweight anchor, large concrete or stone blocks are the most common. But because of their size and weight, these anchors often require a barge to set.

MUSHROOM ANCHORS

Mushroom anchors look like an upside-down mushroom and are made of heavy cast iron. They are best for freshwater and smaller motorized water vehicles because they can be easily buried in:

  • Mud
  • Sand
  • Silt
  • Other soft seafloors

However, mushroom anchors are not best for some conditions. They can dislodge and lose holding power if they aren’t embedded adequately on the sea or lake floor. This is called a spin-out. A spin-out will negatively impact the mooring system’s safety.

It’s also possible for the chain to wrap around the shaft of the anchor if it doesn’t correctly set. This can reduce the mooring’s scope.

If you get a mushroom anchor, find one coated with PVC. The plastic layer acts as a bumper and prevents damage to your watercraft.

PYRAMID ANCHORS

Pyramid anchors are similar to mushroom anchors in that they are made from heavy cast iron and have similar holding power. However, they come in the shape of a pyramid rather than a mushroom.

The pyramid shape allows the anchor to become embedded in the seafloor quicker than the mushroom shape. Plus, because they have a shorter anchor shaft, chain wrap becomes less likely. Unlike mushroom anchors, you can use pyramid anchors on any seafloor, including

  • Hard
  • Rocky
  • Sandy

Pyramid anchors are most commonly used in shallow waters.

HELIX ANCHORS

Helix, or screw pile anchors, consist of helically shaped stainless steel plates attached to a central shaft. They use rotation during installation into the ground.

These anchors are more eco-friendly than others, and their holding strength is unmatched. They work best for marinas and residential float systems in waters no greater than 60 ft (18 m).

You'll need specialized equipment and professional installation to use screw pile anchors in deeper waters.

PILING ANCHORS

Piling anchors are most common to secure floating docks because they drive a single structure into the seafloor for maximum stability and limited side-to-side movement.

You mount the pile loop to the floating dock so the dock can rise and fall with the tide.

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