Scupper Plugs – In Or Out?

Scupper Plugs – In Or Out?

Scupper plugs – what are they for? I mean, if you take them out then water comes in. If you put them in, water builds up anyway. Why bother with them!? They do have a function; they’re not just a silly bit of decoration. I promise.

We’ll find out more as we go along, just wait and see.

What is a Scupper?

A scupper is basically a drain hole. You find them on buildings a lot – they allow rainwater, for instance, to drain off of a flat roof through holes (scuppers) at the base of the parapet or other construction. Sometimes they are ornamental, for instance, gargoyle-shaped!

Of course, ships and other boats also have scuppers on the deck. They simply allow rain water and sea water that has washed over onto the deck to drain away back into the ocean.


So, it must follow then that the purpose of a scupper hole in a kayak is to allow water to drain out of the cockpit, right?

But you see the flaw, don’t you?

Whereas on a larger boat, the scuppers are at deck level, which is usually significantly above the water-level, the scuppers on a yak are in the base of the cockpit. Where the sea is.

What Gives?

Well, the thing is that the deck and the hull of a kayak are pretty much in the same place. As a side note, you’ll pretty much only ever find scuppers in a sit-on-top kayak and not a sit-in kayak.

The purpose of the scuppers in a SOTK is to allow any overwash or paddle-splash to drain out. The inherent buoyancy of a SOTK will ensure that very little water will come in through the holes because they should be placed so as to set pretty much at the water-level for a laden kayak.

What you will find, however, is that more water will start coming in, especially if you have a fair bit of gear in your kayak, or if you are a bit energetic when you climb in and out on the water.

This is purely a design thing. You’re not in danger of sinking, or at least you shouldn’t be. The way a SOTK is made, they are inherently buoyant, so they are very unlikely to sink even if they are filled with water entirely. Having said that, your scuppers shouldn’t be letting in THAT much water. If you are invariably getting soaked through no fault of your own, blame your kayak and get a better one that will look after you!

Too Much Water!

In normal conditions, you will get wet feet and maybe a wet backside because of water in the cockpit. If you are especially laden, there might be quite a bit more water in your cockpit. If this is the case, plugging the scupper holes and using a sponge or a bilge pump to bail out might be wise.

On your average day on the lake or the bay, water will splash into the cockpit from your paddling, especially if you are a bit too excitable! Water also comes from rain and waves breaking on your boat.

This water might start to collect in the bilges and, over the course of a few hours perhaps, it may start to weigh you down. Too much water in your craft puts you at risk of capsizing; it really affects the stability of your boat. Although you probably won’t sink, there is still a risk of tipping over.

This is where the scupper holes come in – the buoyant kayak stays at or near the same level on top of the water, given a static load. Water comes in, and the upward buoyant force on the kayak causes the water to drain out of the lower scuppers, keeping the level of water in the yak pretty much constant.

If you didn’t have the holes, the weight of the pooling water would slowly overcome the buoyancy of the hollow hull, and you’d start riding lower and lower in the water, taking on more and more water, and eventually capsizing or worse.

If you don’t believe me, try it – open the plugs, on the water. Pour a few buckets of water in. It will drain out, and the kayak will just keep floating.

Plugs – In or Out?

I would definitely recommend having your scupper plugs open for most normal situations. They’re there for a reason, and they work damn well too. You may get a wet bottom, sorry. Wear some splash pants, and keep a towel in a dry-bag. You can even wear a dry suit, or just embrace the water. Heck, jump in and have a swim. A bit of water in the bilges is no big deal now, huh?

But seriously, like I said – well-designed kayaks don’t sit so low as to allow a lot of water through the scuppers in normal conditions.

If you don’t think your scupper plugs are of good quality, then I would recommend checking out these universal kayak scupper plugs:

universal kayak scupper plugs

But there are exceptions to keeping them unplugged. If you feel you are taking on too much water, it may be a good idea to put the plugs in and pump or sponge out the excess. The plugs should be attached to a short length of cable, so they can’t go far. Sometimes they’re not, and some kayaks don’t come with scupper plugs at all. If you think you’re going to need them, then get hold of some from the kayak manufacturer or try to fashion some from bottle corks or foam rubber.


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Kayaking through a glacial lake in British Columbia Tag someone you’d paddle here with! #discoverearth by @taylormichaelburk

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Another situation in which it’s great to keep them in is paddling in cold water – I mean like winter water, not “Oooh, it’s 60 degrees – brrrr!”. It can be much more comfortable not sitting in a puddle in January (northern hemisphere crew checking in).

I hope this has cleared up the mystery of the holes in the bottom of the “seaworthy” boat. It definitely took a little faith on my part to believe that water wouldn’t immediately rush in and overwhelm me, but it’s true. So nyah!