The right size surfboard leash will be safer, more convenient, and better for your surfing.
Leash length is the most important variable, and should be determined primarily by the length of the surfboard you’re riding. If your leash is too short, your board is liable to ping back unpredictably and in a dangerous fashion. The force exerted on your leg where it’s attached will be greater, further increasing the chances of injury. Meanwhile the leash cord is more likely to get in the way and restrict your movement.
Too long and the danger posed by your board to others grows in proportion – the longer the leash, the further the range of that projectile attached to your leg. The cord is also more likely to snag on or get wrapped up in rocks, manmade coastal structures, or other surfers. This is bad news for obvious reasons. What’s more, all the excess leash length will cause unnecessary drag as it trails your surfboard through the water, slowing you down.
Leash thickness is also a consideration, however. Thicker leashes are stronger but also cause more drag, so a balance must be struck. Longer leashes are generally thicker so they can withstand the pull of longer (and thus heavier) boards. The other determining factor here is wave size.
What length of leash do you need?
There’s a straightforward rule of thumb for calculating the length of leash needed for your surfboard. Your leash should be roughly the same size as, or slightly longer than, the board you’re riding.
That’s basically all there is to it. Check the length of your surfboard, then look for a leash that’s roughly the same size. For a 6’0” shortboard, a six-foot leash.
This doesn’t have to be exact, but slightly too much leash is preferable to not quite enough. A leash that’s six or even twelve inches longer than your surfboard will still get the job done. A leash a few inches shorter than your board should be OK, but try to avoid going any shorter than that.
Related article: How to attach a leash to a surfboard
What size leash would work for a 7’6″ surfboard?
While some leashes come in six-inch size breaks, most go up in increments of exactly one foot, starting at either five or six foot.
So if your surfboard falls somewhere in between two size breaks, go up rather than down. For a 7’6” surfboard, then, an eight-foot leash will be about right.
One last thing to mention in relation to leash length is the longboard leash, which may differ not only in size but also in the means (or whereabouts) of attachment. Many longboarders choose to wear their leash around the top of the calf or just below the knee, rather than around the ankle.
This is partly on account of the board’s weight and the ankle’s relative frailty. It may also help prevent tangling when cross-stepping up and down the board. Many leashes in the nine-foot-plus range thus feature a strap designed specifically to fit the contours of this part of the leg.
Leash thickness: Regular vs. Comp leashes
Thinner than regular leashes, competition leashes aka comp leashes (or sometimes just lightweight leashes) are conducive to faster surfing and higher performance. The cord’s reduced diameter equates to less drag which in turn equates to greater speed. Obviously most surfers aren’t regular competitors – in practice, comp leashes are synonymous with small waves.
In smaller, less powerful waves you can afford to wear a thinner leash as it will come under less strain. Moreover, speed is harder to come by in smaller surf so leash-drag becomes a more relevant factor, and reducing leash-drag a more pressing concern. It won’t make a huge difference, and you might not appreciate it until you’re riding a shortboard and/or safely in the intermediate bracket. But, marginal gains and all that.
In terms of actual thickness or cord diameter, comp leashes usually start at around 5mm (or 3/16″) thick. Regular leashes will be closer to 7 or 8mm (between 1/4″ and 5/16″). Thicker leashes, typically classed as big-wave leashes, are also available, but only certified hellmen/women will need apply for one of these.
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Why you should always wear a leash
The main purpose of the leash is safety, not just your own but also that of other surfers and ocean-goers. It doesn’t take much for a surfboard to be converted into a dangerous projectile. By keeping it on a leash, you curtail the range of that projectile significantly. More obviously, you don’t lose contact with your surfboard-cum-life-raft every time you fall off.
Even attached to a leash, a surfboard still has a striking range of 10 to 20ft: the length of the leash plus the length of the board. In other words, a leash is just one of several necessary precautions. Others include: holding onto your board, not bailing it when faced with oncoming whitewater; not paddling directly in front of other surfers; not paddling directly behind other surfers. You should always be mindful of where your board is in relation to those around you (and vice versa).
There are some circumstances under which leash-less-ness is arguably permissible, but they generally involve: a) being a highly skilled and experienced surfer, and b) surfing far away from anyone else who might get in the way of your surfboard. Let’s not worry about any of that right now.
Convenience, of course, is the other great benefit of the leash. In the formative years of our chosen pastime, well into the 1970s, leashes didn’t exist or weren’t yet really a thing. Wipeouts frequently resulted in a long and arduous swim back to shore to retrieve one’s wave-riding device.
A fun fact & more safety advice
Fun Fact: Pat O’Neill, son of wetsuit inventor Jack, came up with the initial designs for the leash, which consisted of a surgical cord attached to a surfboard using a suction cup. Unfortunately, it was this prototype that caused the accident that claimed Jack’s left eye.
These days leashes are much safer, but you should still be mindful of your surfboard pinging back at you after a wipeout. This happens very rarely, but still happens. Covering your head when surfacing is a good idea in any case.