A kayak bulkhead is a watertight wall built into the hull of a sit-inside kayak. It divides the hull into separate compartments, creating sealed air spaces that provide buoyancy and waterproof storage.
Most sea kayaks and touring kayaks have two bulkheads: one behind the seat and one in front of the footrests, creating a rear compartment and a bow compartment. Recreational kayaks often have only a rear bulkhead, or none at all.
Understanding how bulkheads work helps you make better decisions about safety, storage, and what to do if your kayak capsizes.
How Bulkheads Work
When a sit-inside kayak capsizes, water floods the cockpit. Without bulkheads, water would fill the entire hull and the kayak would sink below the surface, making it very difficult to right and re-enter.
With bulkheads in place, only the cockpit area fills with water during a capsize. The sealed bow and stern compartments remain full of air, keeping the kayak afloat at the surface and making it significantly easier to right and re-enter.
This is why bulkheads are considered an essential safety feature on sea kayaks and any kayak used in open water. A kayak with intact, sealed bulkheads will remain at the surface even when fully swamped, allowing the paddler to perform a self-rescue or assisted rescue.
Types of Kayak Bulkheads
Fibreglass or plastic bulkheads are the most common type in factory-built kayaks. They are moulded into the hull during construction and sealed with marine-grade adhesive or sealant around the edges. They are durable and long-lasting but can develop leaks over time if the sealant deteriorates.
Foam bulkheads are blocks of closed-cell minicell foam cut to fit the interior cross-section of the hull. They are used in some production kayaks and are the standard choice for DIY bulkhead installation. Because closed-cell foam does not absorb water, it maintains its buoyancy even if the seal is not perfect.
Inflatable bulkheads are airbags or float bags placed in the bow and stern compartments of kayaks that have no built-in bulkheads. They are the most practical solution for recreational kayaks and whitewater kayaks that lack factory-installed bulkheads.
The Limitations of Bulkheads
Bulkheads are not without drawbacks. The most significant issue is that the sealant around the bulkhead edges can deteriorate over time, allowing water to seep into the storage compartments during paddling. This is one of the most common maintenance issues on sea kayaks and touring kayaks.
Check your bulkhead seals at least once a season by filling the compartments with a small amount of water and watching for leaks into the cockpit, or by paddling in calm conditions and checking whether the compartments are dry when you return to shore. Reseal any leaks with marine-grade silicone before they worsen.
A secondary limitation is that if the hatch covers fail and the bulkhead compartments fill with water, the kayak becomes much heavier and harder to drain. Always check your hatch covers are properly seated before launching, and consider whether your hatch cover seals need replacing if they are old or showing signs of wear.
Foam Bulkheads
Minicell foam is a closed-cell foam used in many production kayaks as the bulkhead material. It is lightweight, buoyant, and completely waterproof. No water can penetrate the closed cells, so it maintains its buoyancy even if the surrounding sealant is not perfect.
Foam bulkheads are also used in whitewater kayaks where a moulded plastic bulkhead would be too rigid and prone to cracking on impact. The foam absorbs impact energy while still providing buoyancy and separating the cockpit from the bow and stern sections.
Installing Your Own Bulkhead
If your kayak does not have bulkheads, you can install them using minicell foam. This is a relatively straightforward DIY project that significantly improves the safety of a recreational kayak used in open water.
What you’ll need:
- Closed-cell minicell foam, at least 75mm (3 inches) thick
- A sharp knife or hot wire cutter for shaping
- Marine silicone sealant
Steps:
- Measure the internal cross-section of your kayak at the point where you want to install the bulkhead, typically just behind the seat and just in front of the footrests
- Cut the foam to match the cross-section, slightly oversized so it fits snugly with light compression
- Test the fit and trim as needed until the foam sits flush against the hull on all sides
- Apply marine silicone sealant around the entire perimeter where the foam contacts the hull
- Allow the sealant to cure fully before paddling
The bow bulkhead should sit just forward of the footrests and the stern bulkhead just behind the seat back. This maximises the buoyancy chambers while keeping the cockpit area accessible.
Float Bags as an Alternative
For kayaks without bulkheads, float bags are the most practical alternative. These are inflatable air bags that sit inside the bow and stern sections of the hull, displacing water and providing buoyancy in the event of a capsize.
Float bags are particularly popular in whitewater kayaking where the hull is subject to significant impact and a rigid foam bulkhead could crack. They are also used in recreational kayaks and canoes where no bulkhead is fitted from the factory.
A float bag does not provide sealed storage the way a bulkhead compartment does, but it achieves the same primary safety function of keeping the kayak afloat when swamped.
Read: Kayak Float Bags
Do All Kayaks Have Bulkheads?
No. The presence of bulkheads depends on the type of kayak.
Sea kayaks and touring kayaks almost always have two bulkheads as standard. This is considered a minimum safety requirement for open water paddling.
Recreational kayaks often have a single rear bulkhead but no bow bulkhead. Some entry-level models have no bulkheads at all.
Whitewater kayaks rarely have traditional bulkheads. Float bags are used instead to provide buoyancy without the rigidity of a foam or plastic wall.
Sit-on-top kayaks do not have bulkheads in the traditional sense. Their sealed hull design means the entire hull acts as a buoyancy chamber, and scupper holes allow water to drain from the deck automatically.
Inflatable kayaks do not have bulkheads. The multiple air chambers of most inflatable designs provide the equivalent safety function. If one chamber deflates, the others keep the kayak afloat.
Final Thoughts
Bulkheads are one of the most important safety features on a sit-inside kayak. They keep the kayak afloat when swamped, make self-rescue and assisted rescue significantly easier, and provide sealed waterproof storage for gear.
If your kayak has bulkheads, check the seals regularly and reseal any leaks before they become a problem. If your kayak does not have bulkheads, consider installing minicell foam bulkheads or fitting float bags in the bow and stern to improve its buoyancy in the event of a capsize.
For more on kayak safety and maintenance, read our guides on how to store a kayak and is kayaking dangerous.