Buoyancy for an Open Canoe

Buoyancy should do two things in a boat – provide support and stability.

Firstly if the boat gets totally swamped, the fixed buoyancy should be more than sufficient to float you, your gear and the boat on the surface of the water. If the gunwales of the canoe are supported out of the water, then the water can be removed by bailing. But if any part of the gunwale is under the water then, as you bail, water will just flood back in again, so this must be avoided – by fitting sufficient buoyancy.

Ideally a fully swamped boat will have sufficient freeboard that waves do not come in over the gunwales as you bail. To achieve this you need a lot of buoyancy and you should always carry a substantial bailer, attached with a lanyard so that it cannot be lost overboard.

Secondly, the canoe needs to be stable whilst you bail the water out. To achieve this the buoyancy needs to be located in the ends AND at the sides of the canoe. If you just have buoyancy at one end, that end will be supported but the other end will sink below the water surface. But if you have buoyancy only in both ends, the ends will be supported but any water in the canoe is free to move around. If the canoe heels at all, the free water in the canoe can and will run to the lower side and put your side gunwale under and flood you again or capsize you.

Side Buoyancy

Most open canoes are wide enough that you can fit side buoyancy without interfering with the space needed for the canoe sailor. If the canoe is swamped, the side buoyancy helps to hold the canoe and sailor out of the water by displacing water in the canoe. As the swamped canoe heels, the free water is prevented from running all the way to the side of the canoe, and the bag provides a righting moment which keeps the canoe nearly level. This gives a totally swamped canoe significant stability and reduces the chance of capsizing the canoe. But end buoyancy is also required, otherwise the free water can run to either end and submerge it. (More detail and video below)

End Buoyancy

Paddlers are familiar with end buoyancy bags and canoeists who have had any proper training will understand how useful it is. Flat water paddlers will learn how to empty the water out of a friend’s boat by using techniques such as a curl or X-rescue. In an X-rescue the rescuer comes alongside one end of an upturned or swamped canoe, lifts one end, the other being supported by the opposite end bag. Then they can roll the canoe over to empty the water and return the canoe upright and empty. They can then support one side of the canoe whilst the friend in the water climbs back in over the other side.

Buoyancy bags or built-in decks?

Buoyancy is critical for keeping an open canoe safe and recoverable when the canoe gets swamped after capsizing. Even if you don’t capsize, when beating into a strong wind on a large body of water the resulting waves can become large enough to bury the bow into them, or get significant repeated splashes of water into the canoe. Using only buoyancy bags, any water that lands on them will just flow down into the canoe and increased the risk of eventually being swamped. As the water level in the canoe rises, the freeboard reduces and the chance of burying the bow and swamping the canoe increases. Keeping weight out of the bow area helps the bow to rise over waves but eventually spray and splashes will end up with water needing to be bailed out.

Buoyancy bags must be fitted really well. If the straps holding it into the canoe are not well attached to the canoe, the bags will just float out in a capsize. Ideally each strap and its attachment should be sufficiently strong to lift the canoe up by them. This is easy to check. A minimum amount of buoyancy would be something like a 32 inch shaped end bags and 46 inch long by 10 inch diameter bags in each side, comprising around 300 lbs of buoyancy.

For comparison, a well-designed decked sailing canoe such as a Solway Dory Shearwater has around 1000 lbs of built-in buoyancy and also allows gear to be carried inside some of the buoyancy compartments.

A well fitted out open canoe can have both plenty of buoyancy in the right places and plenty of room for carrying gear for camping etc, with the weight best concentrated near the middle of the canoe. Ideally any space not needed for gear or crew should be filled with buoyancy.

Fabric foredeck on an open canoe

A few of our more experienced sailors with open canoes have added a fabric foredeck on the bow of the canoe, usually stretching back as far as the mast. This is a sensible extra for any open canoe that is going to be sailed on large lakes in strong winds or the sea. Any water that lands on the fore deck is likely to run off over the gunwale and not end up in the canoe. This fore deck is attached with press studs so that it can be removed to stow gear in dry bags in front of the mast. It still has a large buoyancy bag in the bow. Decks do not remove the need for large air bags well fixed in the bow, stern and sides.

Capsize recovery

Capsizing a sailing canoe is not inevitable.

Many of our members sail for years without capsizing accidentally. However it is always worth practising capsize recovery regularly to check that you can still do it competently. We are happy to supervise capsize practice at most of our events.

Having a reefable sail and reducing the sail area when the wind strengthens reduces the chance of a capsize and is a more efficient way to sail anyway. We tend to sail in company of other canoe sailors, so if we do capsize we have help close at hand if we need it. Paddlers on large bodies of water or rivers will often paddle along the shore, knowing that if there was an accidental capsize it’s not far to swim the canoe to shore. Or paddling in company, your buddy can assist by emptying then supporting your canoe as you re-enter.

Typically, sailing canoe capsizes happen away from the shore

But sailing is different, as you will have to sail away from the shore as you tack upwind; swimming a canoe back to shore is not a realistic option. As there is also a mast, rudder and leeboard getting in the way of doing any X-rescue, we must be able to right the canoe and rescue ourselves – this is where side buoyancy really helps. It is fairly straightforward to turn a capsized sailing canoe back upright. The leeboard can be used as a lever to roll the canoe back upright, with the side buoyancy coming into its own by supporting much of the weight of the canoe and emptying most of the water out (with only end buoyancy, as the canoe is rolled back upright there is so much water still in the canoe that it will be very unstable and consequently very difficult to re-enter or even bail out).

When you right a canoe that has sufficient, well arranged buoyancy, it is likely to come up with a small amount of water in the bottom, but not so much as to make it unstable and therefore difficult to re-enter. The side buoyancy still controls the free water in the canoe and prevents it from moving too far sideways, providing some stability and support for your weight as you re-enter the canoe over the side.

How side-mounted buoyancy works in a canoe

It is sometimes difficult to imagine what the buoyancy bags in a canoe actually do. Most of the time the canoe is the right way up and has no water in it. However, if you capsize, the canoe will usually invert. The canoe in this video has the standard end buoyancy bags that most paddlers fit to their canoe. We also have one side buoyancy bag, the other one having been removed for this demonstration. The side bags are 10inch diameter and 46inch long with a buoyancy of 75lbs.To begin with we are standing in shallow water, to show what happens when you roll the inverted canoe back upright.

Firstly the canoe is inverted and then rolled back upright over the side without the side bag. The canoe takes on a lot of water and you can see the water moving around from side to side showing that it has very little stability.

Secondly the canoe is again inverted and then rolled back upright over the side with the side bag. You will notice that the side bag floats in the water and holds the canoe much higher as it is rolled over. The canoe comes up with a lot less water in and resulting in a lot more freeboard.

We then put the other side buoyancy bag in the canoe and strapped it in securely. We swam it out into deep water and did a capsize recovery. I used the centre carrying yoke to hold the canoe whilst i flipped the canoe back upright. As it goes over vertical i pull myself up and kick with my feet to get the canoe over with me inboard. You can notice that the side bag supports the canoe AND some of my weight as i try and re-enter the canoe.

I am not super fit and lightweight (I was 57 years old and 14 stone at the time)  but i still manage to get in without swamping the canoe. When upright you can see the canoe has plenty of freeboard.  As i rock the canoe from side to side it has plenty of stability and it would be easy to bail out the few inches of water and continue.

We didnt put the sailing rig on the canoe whilst doing this video so that it is easy for the viewer to see what the side buoyancy bags actually do in a capsize situation.