How to Measure Your Boat Fenders for the Right Cover Size

One of the first questions we get is simple: what size cover do I need? Good news. We keep it simple and you do not need to hunt down the exact model number of every fender on your boat.

Our covers are built to fit a range of fender sizes, not one single model. So sizing is quick. Here is how to get it right in a couple of minutes.

New to covers? Start with what fender socks are and why boaters use them.

Why our covers fit a range, not one exact fender

We make our covers from a high-performance polyester. It is durable and it has just enough give to pull snug over fenders that are close in size but not identical.

That matters more than it sounds. A lot of boats end up with a mix of fenders bought over different seasons. A flexible cover means one size can handle fenders that are slightly different but in the same range. You are not stuck matching a separate cover to every single fender.

We keep it simple with three sizes: 6.5, 8.5, and 10.5. The majority of common boat fenders fall into one of them.

How to measure your fenders

Grab a tape measure and your fender. You are after two numbers: the diameter at the widest part and the total length of the fender.

• Easiest way: Measure straight across: Lay any standard tape measure across the widest point of the fender, side to side. That is your diameter. Repeat the same process along the length of the fender including fender eyes if they are present.
• Most precise diameter measurement: Wrap a flexible tape measure (such as a sewing tape measure) around the fattest part of the fender to get the circumference, then divide by 3.14. That gives you the diameter.

Write those numbers down. If you have different fenders repeat the process for each.

Match your number to a cover size

Take the diameter and length you measured and use our boat fender cover size guide to see what cover size is best for your fenders.

Fenders that are close in size will usually share the same cover.

Or skip the tape measure entirely

Alternatively, if you already know your fender brand and model, you can skip measuring altogether. We mapped the major fender brands and models (Polyform, Taylor Made, and more) to the right cover size in our fender sizing guide. Find which table your fender model falls in and you have your size.

Why a range fit beats a one-to-one custom cover

Some cover makers create a cover for every single fender model. One cover, one fender. It sounds precise, and it photographs well, but the trade-offs are real.

• You have to know your exact model. A pattern-per-model fit only works if you can name the precise brand and size of every fender. Mix brands or guess wrong and the fit is off.
• Mixed fenders mean mixed orders. If your fenders are not all identical, you are buying different covers for different fenders instead of one size that handles the range.
• Swap a fender, lose the fit. Replace one fender down the road with a slightly different model and a cut-to-model cover may not fit the new one. A range fit keeps working.
  
• Installation and Removal, it's a hassle. Without a drawstring or enough give in the fabric, a one-to-one custom cover can be a fight to get on. Some you have to deflate the fender just to work the cover over it, then pump it back up once it is on. And it is not a one-time chore. Want to machine wash it? You do the whole thing in reverse: deflate, peel the cover off, wash, then refit and re-inflate. Every wash turns into a project.

Our approach achieves the same fitted look through the stretch our fabric provides while keeping the whole process faster, and a lot easier to live with.

Getting the cover on (and looking sharp)

Installation is easy. The cover slides right on over the fender. No deflating, no wrestling. Then you pull the built-in drawstring at the bottom of the fender to cinch it down for a clean, fitted look. Next tuck the drawstring up inside the cover and it disappears. Worried about excess or baggy fabric? Don't be. Our fabric enabled us to provide a fitted look at each end of the sizing range.

Sliding it on and off is just as easy when you want to swap a design or cleanup for the season.

You are set

That is the whole process. Measure and match to a size, or look your model up, and you are done. We built our covers to fit a range on purpose, so the fit is the easy part and picking the design is the fun part.

When you are ready, confirm your size in our fender sizing guide and browse personalized boat fender covers to find a look for your boat.