
What You Need to Know About Boat Fenders
Nov 12, 2021
Boat fenders are used to prevent a vessel from colliding with a dock or with another nearby vessel. They essentially act as a safety cushion between contact points, preventing damage on both sides of the collision. Fenders come in various different forms. There are inflated fenders, foam fenders, cylindrical fenders, spherical fenders and flat fenders.
With so many types to choose from, some people may have a hard time making a decision. To help those people out, we’re going to outline a basic guide on choosing a boat fender. We’re going to discuss the sizing, the orientation and the shape of your fenders. Hopefully, by the end of this guide, you’ll have a better idea of what kind of boat fender is right for you.
Sizing
As a general rule, your cylindrical boat fender should have one inch of diameter (approx. 2.5cm) for every five feet (approx. 1.5m) of boat length. Spherical fenders should have two inches of diameter for every five feet of boat length. Flat fenders are usually sold in three different sizes: small, medium and large. We recommend talking to sellers about the specific sizes of these fenders. Remember, the larger the size, the more protection the fender will offer your boat.
You also need to consider the environment that you’re in. For example, boats that are often in rough waters will require fenders that are larger than usual.
Orientation
You can choose to use your boat fenders horizontally or vertically. The best orientation for you will depend on the type of boat that you have.
For example, there’s the low freeboard fender which is made for smaller boats that are closer to the waterline. The low freeboard fender has a curved top, which allows you to hang it vertically over the railing. This protects the railing from colliding with other vessels that are also close to the waterline.
There are also modular flat fenders. Modular essentially means you can tie one flat fender at the end of another to increase its length. You can then hang the lengthened fender vertically. This particular feature is perfect for tumblehome boats. Tumblehome boats are wider at bottom and narrower at the top. As such, you’ll need a longer fender that can reach the lower, more vulnerable part of your boat.
On the other hand, most cylindrical fenders can be used both vertically and horizontally. If you find that your vertical fenders are swinging around too much, you can simply turn your fenders horizontally.

Styles
Here is a list of the common fender styles and their respective advantages:
- Pontoon Fenders
Used to protect the sharp corners on a pontoon boat
- Two-eye Cylindrical Fenders
Has a hole on both ends, allowing you to hang it vertically or horizontally. You can use a combination of the two orientations with multiple fenders for the most protection.
- Round Fenders
You’ll often see these fenders on fishing boats and other commercial vessels. They are large, spherical and offer a lot of protection.
- Rafting Cushions
These fenders have a large surface area and are typically used to raft vessels together. Due to their flat surface, rafting cushions won’t roll around while your boat is moving.
- Low Freeboard Fenders
As mentioned before, these fenders are suited for smaller boats that don’t have a lot of height. It offers good protection for your railing as well.
- Freedom Fenders
These freedom fenders have a V-shape outer surface that allows it to stay on the piling regardless of the movement of your boat.
- Transom Mounted Fenders
Transom fenders are used for swim steps and the stern of the boat. It protects the contact point from colliding with the dock. They are typically rounded, but there are flat transom fenders as well.
Accessories
Yes, fenders are used to protect your boats. But sometimes, you also need to protect your fenders as well. You can do this through fender accessories.
You can get fender covers so you can shield your fenders from dirt and contaminants when not in use. There are fender racks that are designed to store your fenders and keep them ready for deployment. There are even special pumps that you can use so that your fenders have the right air pressure.
Hopefully, this gave you a better understanding of the different types of boat fenders. When choosing a fender, it’s important to think about your particular needs and preferences. If you need more advice, we suggest talking to boating product specialists. They should be able to explain your different options as well as offer some practical advice on how to make the most out of your fenders.