The Ultimate Guide to Mooring Bollard Types: Which One Fits Your Port?

Choosing the right mooring bollard¹ can feel like navigating a maze. With so many shapes and sizes, how do you know which one will keep your vessels safe and your operations smooth?

The answer depends on your specific port conditions², vessel types, and mooring angles. In this guide, I will break down the most common bollard types—Single Bitt, T-Head, Kidney, and Double Bitt—so you can make the best choice for your project.

Let’s dive into the details. I have seen many projects succeed or struggle based on this single decision. It is not just about holding a rope; it is about efficiency, safety, and long-term value.

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Single Bitt Bollards: Why Are They the Most Versatile?

Single Bitt bollards³ are often the first choice for many ports. But why are they so popular, and does their simplicity mean they are the best option for you?

They are designed to handle steep mooring line angles⁴ and offer a compact footprint. This makes them incredibly versatile for berths that handle a wide variety of vessel sizes.

I often see Single Bitt bollards used where space is tight but performance cannot be compromised. The design allows for a large range of line angles, both vertically and horizontally. This is crucial when you have vessels with different freeboard heights docking at the same berth.

The shape is simple, usually a single post with a cross-bar or a wider top. This simplicity is its strength. It is easy to cast, easy to install, and easy for line handlers to use. There are no complex curves to trap lines or cause excessive wear. If you are unsure about the exact mix of vessels calling at your port, the Single Bitt is often a safe and reliable bet. It handles the "general purpose" role better than almost any other type. However, for very large vessels or extreme tidal ranges, you might need something more specialized.

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T-Head (Staghorn) Bollards: Do You Need Higher Line Angles?

You might have seen bollards that look like a letter "T" or have horns curving upwards. These are T-Head or Staghorn bollards, and they are my personal favorite to recommend.

They are built to handle high line angles, preventing the mooring line from slipping off even when the ship is riding high or the tide is extreme.

At Jettyguard, the T-Head bollard⁵ is actually our most shipped type. Unless a customer has a very specific request for a different design, I almost always recommend and quote the T-Head type first. Why? There are three main reasons.

First, the design is efficient. It achieves high strength with less material weight compared to a blockier Single Bitt. This saves on material costs and shipping. Second, the structural strength is impressive; we can easily manufacture these to handle Safe Working Loads (SWL)⁶ of hundreds of tons. Third, and perhaps most importantly, they accommodate large mooring angles. The "horns" of the T-shape act as a catch, ensuring the line stays secure even if it is pulling steeply upwards. This gives port operators peace of mind. It is a design that balances cost, strength, and functional safety perfectly.

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Kidney and Cleat Bollards: Are They Only for Small Vessels?

Kidney bollard⁷s and Cleats are smaller and simpler. But does that mean they have no place in a commercial port, or are they strictly for marinas?

They are primarily used for smaller applications where line angles are low and loads are lighter. They are cost-effective but have limitations you must accept.

You will often see Cleats on private docks, marinas, or for small fishing vessels. In my experience, we rarely supply Cleats with a capacity over 30 tons. Most of the projects requesting them are quite small.

Recently, I have noticed a trend where marina projects are trying to cut costs. They are switching to cast steel cleats with very low Safe Working Loads, often just 1 to 5 tons. While this saves money, it is vital to remember their limit. A kidney bollard is slightly more robust and is good for general commercial use where tides are small. It has a smooth, rounded shape that is gentle on ropes. But if you have a steep line angle, be careful. The line can slip off a kidney bollard more easily than a T-Head. Use them wisely, mainly for sheltered waters or specific vessel sizes where you know the mooring conditions will remain mild.

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Double Bitt Bollards: When Should You Use Two Posts?

Sometimes one post is not enough. Double Bitt bollards⁸ feature two vertical columns. When is this extra complexity worth the investment?

They are used when you need to secure multiple lines from a single vessel or when you need to "warp" or shift the vessel along the berth.

Double Bitt bollards are like the heavy lifters of the bollard world. Having two columns allows for a better distribution of force and provides more room for lines. This is particularly useful for larger ships that might put out multiple lines to the same point.

Another key advantage is for warping operations⁹. If a ship needs to shift its position along the quay without using a tug, the Double Bitt design allows lines to be crossed and manipulated more easily than a single post. They often have a smaller base area relative to their capacity, which can be helpful on narrow jetties. While they are more expensive than a Single Bitt or T-Head, their operational flexibility for large commercial vessels often justifies the cost. If your port handles large cargo ships or tankers, you will likely need a few of these in your layout.

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Material Matters: Ductile Iron or Cast Steel?

The shape is important, but what about the metal itself? The choice between Ductile Iron¹⁰ and Cast Steel¹¹ is a technical one that affects longevity and cost.

Ductile Iron (Spheroidal Graphite Iron) is generally the superior choice for marine bollards due to its corrosion resistance¹² and cost-effectiveness.

I always advise clients to look at the long-term picture. Cast Steel is strong, yes, but it rusts much faster in a marine environment¹³. Unless you have a rigorous maintenance plan to paint them frequently, they will degrade.

Ductile Iron, on the other hand, has excellent corrosion resistance¹². The graphite nodules in the iron structure act as a barrier to rust. It is also generally cheaper to cast. This means you get a product that lasts longer and costs less upfront. That is a win-win. We do supply Cast Steel if a project specification strictly demands it—sometimes for extreme low-temperature environments where impact toughness is critical—but for 95% of ports, Ductile Iron is the smarter engineering choice. It offers the best balance of strength, durability, and value.

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Conclusion

Selecting the right mooring bollard¹ is about matching the design to your specific needs. Whether it is the versatile T-Head or a simple Cleat, making the right choice ensures safety and efficiency for years to come.

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