If you’re installing a new dock or replacing some existing cleats, there are several things to know before purchasing a set of these. Several factors come into play, including length, material, and some personal preference options worth understanding.
In this post, I’ll break down what to know about dock cleats in general so you will be able to select the right choice for your dock.
The difference in boat cleats vs dock cleats
The main difference between boat cleats and dock cleats is that boat cleats are going to come on your boat from the manufacturer and really dictate the diameter of rope needed to support your boat.
While boat cleats and dock cleats may look similar, the main differences are the way they are mounted. Typically dock cleats will be much larger, especially at marinas, in order to accommodate for larger boats that require thicker rope to secure.
As a rule of thumb, the bigger the dock cleat the better. While both boat cleats and dock cleats have similar designs and styles, it’s important to ensure that whatever dock cleat you mount will be able to support the weight of any boat that could possibly tie up to the dock.
Types of dock cleats to choose from
When it comes to selecting a type of cleat, one thing to keep in mind is that many of these designs aren’t necessarily better than any of the others, they are simply based on personal preference. When it comes to strength, most of the galvanized cast iron dock cleats are the traditional horn style dock cleats, and generally the strongest and most popular.
Horn dock cleats
The common type of dock cleat you’re likely to see are horn-style dock cleats. These come in a variety of materials, and most larger cleats fall into this category.
Flip-up dock cleats
Flip up dock cleats (or fold-up) are one of a couple of types of cleats you can purchase that are designed to stay hidden when not in use. While they function like standard horn-style dock cleats, typically you will find these in smaller sizes, since they include hinges.
As a general rule, the less moving parts the better (when it comes to securing large boats), but these are a fine option for smaller boats found in lakes or reservoirs.
Pop-Up dock cleats
Similar to flip-up cleats, pop-up (or pull-up)cleats are usually stainless steel, and designed to stay out of the way. While these aren’t ideal for larger boats due to their moving parts, you really never have to worry about stubbing toes with these.
With pop-up cleats these come with backing plates, which allow you to secure them to the underside of the dock.
“S” dock cleats
These dock cleats are popular for their look and general form factor. Some people prefer the “S” shape, because it makes it easier to loop rope around and tie off as opposed to standard horn-style cleats.
Mooring bollards vs dock cleats
As opposed to a dock cleat, mooring bollard is actually a short vertical post used as an anchor point for ships. Similar to typical dock cleats, you can also find mooring cleats, which all have a vertical protrusion.
The main difference in these is that the mooring cleat (or bit) come in S or T types for consumer use, but typically mooring lines and bollards are referred to in the context of larger ships.
Mooring bollards are more practical in design for securing yachts and ships with numerous lines as opposed to cleats, which commonly secure a smaller boats and aren’t designed to handle very thick rope.
Dock cleat materials to choose from
When it comes to materials, there are several options to consider before making a selection. Some are more expensive than others, as well as generally less resistant to tension and wear, so these factors must be considered. For most people with relatively smaller boats, it really comes down to cost.
Nylon dock cleats
Since nylon is really just a synthetic polymer or plastic made, these will typically be the cheapest of any dock cleat on the market. With that said, these do tend to be the weakest of any type of cleat, and not meant to handle larger boats.
While theses are generally less common, they do make plastic dock cleats in the horn type which can be more economical if you plan to install a large quantity of these.
Aluminum and stainless steel dock cleats
The most common variety you will see are stainless steel dock cleats, due to their resistance to the elements. The main difference in aluminum vs stainless steel cleats in general is their resistance to corrosion.
Cast iron dock cleats
The strongest and heaviest of all dock cleats fall in the cast iron category as you might expect, and while not shiny like stainless steel, they are a solid option, especially at the coast.
These you typically see on concrete docks as well. Since they are heavier, you will want to make sure they are installed correctly and secured according to specifications.
Understanding the strength and reliability of dock cleats
The strength of dock cleats depends on several factors like build material, fasteners and backing plates, number of holes, strength of the rope, and the integrity of the plank you are attaching it to.
Any one failure of any of these components can cause a dock cleat to fail. This article on the Boat US Foundation website breaks down dock cleat failure loads and several other factors to consider based on material.
How many dock cleats to install?
As a general rule, many dock owners install dock cleats 7 to 10 feet apart, depending on the size and number of boats expected to use them.
Dock cleats per boat
For smaller boats, using at minimum two dock cleats is typically perfectly okay: one for the bow line, one for the stern line, and both of the cleats supporting the spring line.
This diagram from BoatUS.com helps to illustrate a typical dock line configuration in relation to the cleats.
What size dock cleat to choose (and dock line)
For boats around 21 feet or less, you will need ⅛ inch diameter dock line for every 9 feet of boat.
For example, if you have a 36 foot boat, will need ½ inch diameter rope, since (36/9) x (1/8)= 1/2.
How to calculate dock cleat size based on rope diameter
In inches (from tip-to-tip), your dock cleat should be one inch for every 1/16th of dock line you use.
For example, if your dock line is 1/2 of an inch thick, and there are eight sixteenths in ½ of an inch, you would need the cleat to be 8 inches long from tip to tip.
How to install dock cleats
To install dock cleats, secure them to the underside of a single plank using included hardware; heavy-duty dock cleats made of cast iron include a joist corner which should be mounted to the bottom of the plank and the post, forming a right angle. By anchoring a dock cleat to a post and plank, stress on the plank is reduced (which can cause the plank to break or come loose).
Below is a helpful video that describes this process. These are secured by carriage bolts, with lock washers and nuts.
Tip: Never install dock cleats in between two boards; you can end up putting unwanted stress on the boards, causing them to crack, become loose, or even break.
You might also want to check out my post on boat dock railings if you’re giving your dock an upgrade.
Now that you know all about dock cleats, consider the following factors before you purchase a kit:
- What type of boats you have
- How heavy your boat is
- The strength of the cleat itself
- The dock surface you are mounting to
I hope this post has helped! Be sure to check out this post where I cover dock lines 101 for beginners on a few best practices.
This post was updated on August 3rd, 2022.