Sit-on-Top Kayak Scupper Plugs – Why Does Your Kayak Have Holes?

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If you have a sit-on-top kayak, you may be a little dubious about the purpose of the holes drilled into the deck. Sure, they might help drain water out, but won’t they also let it in?

Well, yes, sometimes they do.

If that’s a problem, then you need to invest in some kayak scupper plugs. Kayak scupper plugs fit inside the scupper holes in your sit on top kayak. Scupper holes help drain water from your kayak, but sometimes, water can splash up through the holes, giving you a wet butt. Scupper plugs keep you dry and make kayaking more comfortable.

Find out what they do and the different types available in this article.

Key Takeaways

  • Scupper holes are self-bailing holes in sit-on-top kayaks that allow water to drain out of the cockpit area.
  • Scupper plugs are rubber or plastic bungs that fit inside scupper holes to prevent water from splashing up into the kayak, keeping you dry and comfortable.
  • Scupper plugs are optional and depend on personal preference but you should leave the scupper holes open in rough waters or when kayak surfing.
  • Measure the size of your scupper holes to find compatible plugs. You can also make DIY scupper plugs using foam golf balls, rubber stoppers, or chair tips.
  • Scupper valves are an alternative to scupper plugs that have a one-way valve that lets water out but not in.

Why Does Your Kayak Have Holes In the Bottom?

A sit-on-top kayak has an open cockpit. Any water that splashes inside the kayak will collect in the cockpit area. You’re unlikely to get much water in your kayak in calm, flat-water conditions. However, if you’re kayak surfing, paddling in rougher waters, or you get caught in the swell from a passing boat, you may quickly find yourself ankle-deep in water.

That’s why sit-on-top kayaks come equipped with self-bailing holes. These allow water to drain out of the cockpit area, so the kayak doesn’t become swamped. Most sit-on-tops have 4–6 scupper holes spread along the length of the kayak.

Sit-in kayaks don’t have scupper holes as their enclosed cockpit stops water from splashing into the cockpit. A spray skirt keeps the inside of the kayak completely dry. If you do get water in a sit-inside kayak (e.g. if you capsize), you’ll need to bail it out manually.

What Are Kayak Scupper Plugs Used For?

Kayak scupper plugs are small rubber or plastic bungs that you use to plug scupper holes. This may feel counter-intuitive, since they’re a safety feature. But scupper holes do have some downsides.

Although they’re designed to drain water out of the kayak, as mentioned – water can sometimes splash up into the kayak.

The amount of water that comes into the kayak from scupper holes is minimal, but it can be uncomfortable, particularly in cold weather. Scupper holes are often located in the kayak seat, meaning you end up with a wet butt.

Using scupper plugs can help you stay dry and make kayaking more comfortable.

Do You Need Scupper Plugs On a Kayak?

This really comes down to personal choice. If you mainly kayak in warm weather and you don’t mind getting a bit wet, then you may not need scupper plugs at all. For kayak surfing or whitewater, you should leave the scupper holes open as you’re likely to take on a lot of water.

There are two situations when you may need scupper plugs:

  1. When the water and air temperatures are cold and you want to stay dry
  2. If you regularly get water coming up through the scupper holes when paddling on flat water

The closer you are to your kayak’s weight limit, the more likely you are to get water coming up through the scupper holes.

If you have the right size of kayak for your weight, then your kayak should sit high enough in the water that you don’t need scupper plugs. However, big guys and gals may find that even with a high-capacity kayak, water sometimes splashes up through the scupper holes.

The only way to know if it’s going to be an issue for you is to take your kayak out on the water! Go paddling on your local waters a couple of times before deciding whether or not you need to buy scupper plugs.

If you’re worried about your butt getting wet, you could upgrade your kayak with a seat pad or raised frame seat. This will be more comfortable than sitting directly on the deck and avoids the need for scupper plugs.

ALSO READ: Are sit on top kayaks better than sit in kayaks?

How To Install Kayak Scupper Plugs

Scupper plugs are easy to install — if you have the right plug. Before you use scupper plugs, measure the size of the scupper holes in your kayak. Then check the description of the plug you’re looking at to make sure it’ll fit before you buy.

There are two types of scupper plug:

  1. Universal plugs – these rubber plugs are usually tapered to fit different sized scupper holes
  2. Screw-in plugs – these plastic plugs have a screw-in design and are specific to the size of the scupper hole

To install universal scupper plugs, simply push the plugs into the scupper holes. You can check if you’ve got a watertight fit by pouring some water into your kayak and lifting it up. If water leaks out then either you didn’t install the plugs correctly or they’re the wrong size.

Before installing a screw-in plug, you need to make sure that the thread is compatible with your scupper hole. To install, screw the plug in until it’s hand tight. Don’t over tighten it, otherwise you’ll struggle to unscrew it when you need to remove the plug.

Are Scupper Plugs Universal?

Many scupper plugs claim to be universal, but this isn’t quite true. Scupper holes vary in size, and if your scupper hole is at the extreme end of the scupper plug’s size range, you may end up with a poor fit.

Universal scupper plugs are best described as “one size fits most”.

If you’re not sure whether a scupper plug will fit your kayak, try checking online reviews, left by customers who’ve made a purchase. Reviewers often mention which model of kayak they use and how well the plugs worked.

DIY Scupper Plugs

Scupper plugs are cheap to buy, but there are various DIY solutions if you have the materials lying around at home. For example, you could use foam golf balls, as in this video.

You can also make DIY scupper plugs using rubber stoppers or even rubber chair tips.

Here’s how in 3 easy steps:

  1. Drill a hole through your rubber stopper.
  2. Feed a piece of paracord through the hole.
  3. Tie a knot in both ends of the paracord.

You can also add a metal washer that’s the same diameter (or a little smaller) than the thin end of the stopper. This will help prevent the knot from pulling up into the hole when you remove the scupper plug.

What Size Are Kayak Scupper Holes?

Scupper holes vary in size depending on the make and model of the kayak

Some kayaks even have different sized holes in the footwell vs on the seat. Most manufacturers don’t publish the exact size of the scupper holes in their kayaks, so you’ll need to measure the holes in your kayak before you buy scupper plugs.

Some manufacturers publish a chart detailing which of their scupper plugs are compatible with different kayaks. This may be the best way of getting a precise fit, but you’ll often pay a bit more for your scupper plugs. 

Do You Leave Scupper Plugs in a Kayak?

It’s best practice to remove scupper plugs when you’re not using your kayak. Thermo-molded plastic kayaks expand and contract in response to temperature changes. If you leave your kayak in the sun and it heats up, the plastic may expand around the scupper plug, preventing you from removing it.

In extreme cases, leaving your scupper plugs in could even dent or crack your kayak’s hull.

What About Scupper Valves?

Scupper valves are an alternative to traditional scupper plugs. The plug contains a one-way valve, which allows water to drain out of the cockpit but prevents water coming up into the kayak.

Scupper valves may sound like the perfect solution to the dilemma of whether or not to use scupper plugs. So why doesn’t everyone use them?

For a start, scupper valves don’t fit every size of scupper hole. Ocean Kayak and Old Town both make a scupper valve but they’re only guaranteed to be compatible with their kayaks. Scupper valves are also more expensive than scupper plugs and require a bit of maintenance to ensure the valves don’t get blocked. 

If you can’t find scupper valves to fit your kayak, you could try this DIY method which uses a bouncy ball to create a one-way valve.

How To Get Rid of Excess Water From a Kayak

If you paddle a sit-inside kayak, then you may already carry a bilge pump to help you empty any water that finds its way into your cockpit. You may not need a bilge pump if your sit-on-top kayak has self-bailing scupper holes — unless you’re plugging the scupper holes.

Alternatively, you may prefer a kayak sponge. These are used to soak up small amounts of excess water that accumulate in your kayak. A kayak sponge is your best option for getting rid of the small, yet annoying, volume of water that comes up through your scupper holes.  

YOU MAY ALSO LIKE: How to paddle a sit on top kayak without getting wet?


Hopefully, you now know everything you need to know about scupper plugs! These small, simple tools can be the difference between being wet and cold, or warm and dry when paddling a sit-on-top kayak in cold weather.

They’re inexpensive, easy to install, and you can even make them yourself using simple materials you may have at home.

Have any questions we haven’t answered? Post them in the comments below.

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