Wet or Dry – Leaking or Normal? We give you the low-down on Kayak Hatches
Submarine hatches are waterproof. Some Kayak Hatches are almost completely waterproof. Other Kayak Hatches keep the worst of the water out but may let a little through to the inside of the kayak. To put simply the more complex a hatch the more it will leak at some time. Sometimes you may find a cup or two of water inside your kayak - is this normal? If your kayak has a certain type of hatch then it may well be. If you want the inside of your craft to stay 100% dry... buy a submarine instead!
Let's take a look at the various types of kayak hatches and discuss their ability to keep water out of your kayak!
Rubber Hatch Covers For Kayaks
The rubber hatches used on advanced expedition sea kayaks and some other kayaks like the Feelfree Nomad and Perception Triumph 13 are the driest because they are fitted over a moulded lip around the hatch opening. Rubber hatch covers tend to have a tight fit and can be a little tricky to put on and take off. Some silicon spray applied to the hatch rim and hatch cover lip will make things easier to slip these on and off. Time and use will eventually take its toll on rubber. The cover will stretch a bit and eventually perish, especially where UV light and saltwater are involved. Your car tyres don’t last forever, nor will your hatch cover!
Dual-density hatch covers are becoming more popular. Their tough hard plastic inner, with fused soft rubber outer makes it a bit easier to put on and take off these hatch covers, and they still retain an excellent seal to keep water out.
Screw Hatch Covers For Kayaks
These are quite reliable bits of kit. Any leakage is more likely to be around the hatch seating than the twist hatch seal itself. Nearly all kayak manufacturers use a sealant that in our opinion is too thin when applied. Twisting, heating and cooling of the kayak can allow these hatches to leak a tiny bit. If we find a hatch that is drinking too much we fix it with Arbor seal. This is 5mm diameter sticky gunk that stays where you put it no matter what. Some of us used Arbor Seal whilst working on ships and submarines in another life. This is a useful link http://www.arbo.co.uk/arbo-sealants/. Another good option is Sikaflex EBT+ Clear.
Time will take its toll on rigid screw hatches, as their relationship with sand is not good. Also these rigid plastics ever so slowly absorb water and swell. I love my Hobie Outback to bits, but the round hatch will need renewing long before the kayak will – you can't do anything about the laws of physics.
Twist-Lock / Click-Seal Hatch Covers For Kayaks
These are now all the rage and make selling a kayak much easier and come straight from the "add a gizmo" shelf. These hatches perform quite well when water falls directly onto the hatch. Minor leakage will occur in rougher conditions and when working hard at self rescue routines. Water ingress will be less than a few litres and will not prejudice the stability of the kayak. Do not be surprised if your kayak has a jug full of water inside after a day paddling around in choppy waters if you have this style of hatch on your kayak. A price to pay for quick and easy access to the inside of your kayak.
To be called a hatch cover the fitting must be designed to prevent/reduce water ingress into the kayak. A hatch "cover" is something completely different. Take the bow cover on the Feelfree Moken 12 as an example. It is not a watertight fit nor was it ever intended to be so. It is a fixed cover that you can safely open afloat which does not open up to the inside of the kayak. You can slosh some refreshing water over your catch and the water runs out through the scupper holes. Provision is made for your plotter battery in this space but that should be stowed in a dry bag. Other examples of non-hatch covers are tackle console lids and storage area covers often found on fishing kayaks.
No, I hear you cry! I hated this stuff at school (but this is really useful stuff for a kayaker to know).
(P1 x V1) / T1 = (P2 x V2) / T2
P = Pressure
V = Volume
T = Temperature
1 = Outside of Kayak
2 = Inside of Kayak
Your sit on top kayak is sat on the beach at 30C when you close the drain plug and throw yourself and the kayak into the cooling English Channel at 15C. T2 drops as must P2 and your kayak will suck air and water into itself until P2 = atmospheric pressure. The reverse is also true. You beach your kayak and leave it in the sun with the drain plug sealed. T2 rises as must P2 and if that’s as much as ½ a PSI (sorry I still do Imperial Units) and your kayak surface area is say 3 sq yards 1 x 3 x 36 x 36 = 3888 lbs force (hull and deck). You will be very glad your hatch leaks a little to allow the pressure to dissipate – better still undo the drain plug.
Did you know?....
Composite (Fibreglass or Carbon) sea kayaks usually have a small hole in their “watertight bulkheads” to balance the air pressure inside, otherwise with the best of hatch seals the kayak could be split under a build-up of pressure! Some sea and touring kayakers will pierce a pinhole through their rubber hatch covers to allow air to seep out slowly if the pressure builds inside. A pinhole will let negligible water back in - the rubber sort of closes off the hole until pressure stretches the hatch and finds the route of least resistance to escape... through that tiny hole!
We are full of useful information at Canoe Shops. We are all paddlers after all!