VCP Hatch Expansion

I noticed in the heat that the rear hatch cover was ballooning up from expansion. Someone metioned drilling a tiny hole at the top of the rear bulkhead to allow the pressure to equalize. Is this a good idea? How much water would get back in in a capsize?

Should I just forget about it because it would not pop off? Anyone experienced with this? Thanks.

what kind bulkhead, what kind of kayak?

It happens all the time…
What you need to do is “burp” the hatch. Heat builds up at a differnent rate inside and outside of the bulkhead. Heat builds pressure and balloons the hatch. You will also see the hatch suck in when it gets cold quickly. It happens when the bulkheads are air tight. Make you wonder why this doesn’t happen to other kayaks?

We, at P&H, drill a small hole in each blukhead for that reason. It works pretty well and unless you swamp the boat, you won’t have any issue whatsoever. I have a Capella that doesn’t have the holes drilled in and it balloons as much as my old Valley’s did.

The hatch won’t pop off as a rule but the excess pressure over time my have an effect on the hull. I have no experience of this happening but in a theorital world it’s possible.

Hope I helped.

IF you drill. . .
a hole in the top of the bulkhead and you capsize the hole will now be at the bottom and possibly below the water line and letting water in. Try drilling it in the center of the bulkhead. But drill a very small (very, very small) hole.

if you don’t drill . .
you’ll have a visual reference indicating the integrity of the compartment’s waterproofness.

I have 4 boats from NDK/VCP combined and not one of them needs to have the bulkhead drilled. The air expands as it warms and contracts as it cools. The hatch covers bulge up or down. What’s the problem people are trying to “fix” here?

If I’m uncomfortable with the degree of deformation of the hatch cover I just burp the cover and all is mellow once again. Has anyone ever had a boat break from overly air-tight hatch covers?


I have never bothered to drill either. I have wondered if the expansion and contraction of the hatches shortens their life. They don’t seem to last more than two years in Florida, even storing them out of the sun.

I have heard one story (urban legend?) of a glass kayak being damaged when the owner left the hatches on and drove it from sea-level to high in the mountains. I don’t have any details…

Greg Stamer

I am with the other fella here…
There is no reason in my mind for you to drill holes in your boat. It will be just fine as it stands. Holes in the bulkheads are fine but at the end of the day, we will all come home safely. Burp or drill, either way you are paddling a good boat from a good company and it’s nothing to worry about.

I agree with Kelly…

I have a roto P&H Capella and when it’s warm out…I have to burp her rear often…


Decent bulkheads…
Made by VCP/P&H/NDK and anyone else bothering to make them from composite or welded plastic in RM boats give the user so many more options. It’s a helpful item to aid in narrowing your choices down if you are stuck trying to figure out which boat to buy.

I’m with Greg and Jed, as I’ve not vented mine and don’t really want to. Don’t see the problem.

Rob G

VCP bulkheads
I pierced mine with a 1/32 inch bit and it takes care of the problem. The holes are large enough to allow the air to move as it expands or contracts, and the hole is small enough that the water surface tension keeps water from migrating from one compartment to another. I have practiced rolling and wet exits enough, and never a drop in any of my compartments…


Me Too
I have vented the bulkheads in my NDK Romany and Explorer as suggested by NDK. No water in any of the compartments after rolls (how could it if successful?) or wet exits. Anyway, just how much water could go through such a small hole in a reasonable time? We aren’t talking about days or weeks here (I hope) I water were to migrate, it would only be a few droplets.

Hull Damage…
Not in a kayak but a wooden catamaran. I closed the hatches on a cold day and then left it out in the sun for a week. When I returned on hull looked like a balloon. Major structural internal damage was done.

Why would anyone want their hull to be continuingly stressed no matter how slight if all it takes is a pin hole to stop it?

Kind of makes you wonder about those gelcoat stress cracks.

water migration from drilling
I’m not 100% sure but in order for the water to flow from the submerged cockpit into your hatch, wouldn’t the water have to displace some volume of air. How would the air get out to allow the water in. I would rather reduce unnecessary stress on my boat, DRILL AWAY!

a matter of degrees . .
What little stress my hulls endure from expansion / contraction of the air within the hold is nothing compared to stress and blunt trauma they endure from hitting rocks and being bounced around by the likes of me.

My hatch covers are burped after the boat is on the water and are never used off the water (like during transport or storage) so I never see significant deformation of the hatch covers.

Stress-cracks are most often a function of rigid materials and design compromises, exacerbated by stress risers in the form of rigid bulkheads. Regardless, I’ll take my boats complete with stress cracks over a lesser hull any day.



A small hole 1/32 drilled about center of each bulkhead equalizes pressure. Lots of small nagging leaks can be cured by drilling. YES, you read that correctly! The reason is simply that you are relieving vacuum. Toss your yak into 47 degree water on a hot day and watch your hatch covers suck down. This isn’t a problem, but what is also going on is water is being drawn to that area of low pressure through the smallest of voids. I’ve found my hatches to be drier over the years after drilling this small hole. In glass bulkheads this hole can be taped over for full on rescue sessions where flooding of the cockpit will occur. Even when flooded you get very little water through such a small hole. My experience is that drilling is a smart thing to do. Valley hatches are excellent.

Exactly right…vent 'em
I’ve vented the bulkheads in every boat I’ve owned and have yet to get any water in that could be attributed to the tiny vent holes (1/32"). My experience is the same as Salty’s; the boats stay DRIER with the vents than without.

FWIW, I drill the holes slightly above center, the premise being that an inverted boat will never have much water in the cockpit - since it can flow out - but it could have a lot of water in it when it’s upright. In the long run, the hole location probably doesn’t make much difference as long as it’s well above the bottom of the hull.

With foam bulkheads, I poke a piece of wire through the bulkhead, then insert a piece of plastic tubing (the type that comes in spray lube cans) in the resulting hole. Trim it off flush with a sharp blade (a wood chisel works well) and it’s done.

While the likelihood of hull damage with unvented bulkheads is probably small, combine the stress it causes with an impact and it’s quite likely that the resulting damage will be more severe than it would have been without the additional stress. Considering how easy it is to eliminate the problem, I don’t see any point in taking that chance.

BTW, you can often find tiny drill bits cheap at places that sell used tools, as surplus bits used for drilling circuit boards are commonly available. You’ll want to buy a few, since they break easily. I got a box of 50 of them for under $5.00.

My wifes boat was damaged when we went from 500’ to 4500’. The bulkheads are now drilled. It only takes a small hole (1/32") to relieve the presure and you do risk damaging your boat under certain conditions. I also know of one boat that suffered pressure damage when it went from 8000’ down to 500’. The better the hatch seal, the greater the risk of damage.

I vented mine too
I went to the local hobby shop and bought a piece of 1/32" music wire. it is a hard wire, that won’t bend easily. I cut a 3" piece off of the piece of wire using a wire cutter, and just used it for a drill bit. A wire cutter will leave a sharp end, which will work fine as a drill. This works fine for materials that are easy to drill.

I drilled a small hole at the top of my bulkheads, as I am not one for rolling. I hated seeing the VCP covers either bulged up, or sucked down. I have heard of times where the hatch cover was sucked down, and it drew in water which was around the edges of the cover.

I have not had any trouble with water in any of my 3 compartments!

I vote “drill”! :slight_smile:

in rescues
I can’t help but think that a vented bulkhead would reduce the possibilility of an oval rubber hatch sucking water back in when a plastic hull is flexed or a paddler climbs across the rubber hatch.