Drilling my bulkheads

A friend of mine advises that I drill a small hole in each bulkhead to prevent air pressure from building up to the point where the hatch cover, or the bulkhead itself, is damaged. This sounds farfetched to me, but I have noticed that on very hot days my hatch covers do bulge some, so perhaps there is some truth to this. However, my hatch covers and bulkheads are nicely watertight and I am reluctant to compromise this feature without a good reason. Anyone have experience with drilling holes in bulkheads? Did it relieve the pressure without unnecessarily compromising watertightness?

Drilling bulkheads.

– Last Updated: Aug-17-07 9:26 PM EST –

Many manufactures pre drill BHs at the factory. Many folks drill a hole in the center of the BH with the smallest bit you can find.

Check first to make sure they are not already drilled.

grey is right regarding mfg’s
I wouldnt hesitate to do it if I were you. Only trouble I’ve had is rolling practice, in which I seem to get more water in the rear bulkhead than I’d like, while the front stays almost dry.

good luck

Do it…and relax

Why not call the manufacturer ?
Even though we know there should be a small hole to relieve the pressure, I wouldn’t drill it without checking with the people who built it.



Just do it
There’s not a single good reason not to, but several reasons that you should. If you can find one, use a 1/32" bit.

I drilled mine…
to the size of the tube on a WD40 spray can then without shortening the tube, force it in the hole. That relieves all the pressure and water never leaks.


I can’t imagine any…
…recently built kayak without the holes in BH’s. Drill them.

a 1/64 th is better :slight_smile:

This seems odd to me. Do your hatches fit so tightly that you actually hear an air hiss when you open them? My Pelican camera case is vented with a bit of Gore-Tex fabric, which passes air but blocks water.

Hiss you bet
Yes, hatches that fit well are often tight enough to give you a hiss - and to bulge up in alarming fashion when sitting in the sun. I’ve never heard of actual damage being done, but drilling the bulkhead puts my mind at ease…


Burp the hatch covers
Just lift the hatch cover during a break and release the pressure. Of course if you are in the open sea alone you can’t do this.

Depends where you are
I paddle where there can be huge differences between water temp and air temp, plus huge changes in elevation from home to paddling location. These things add up to weird effects on hatch covers.

My Tempest’s hatch covers bulge (and hiss when burped) after being removed from the water and sitting in hot air even for a few minutes. They also suck in noticeably when first put in cold water on a hot day. As the BH’s are foam, I am leaving them undrilled–the flexible rubber hatch covers provide some room for expansion.

On my wood boat, the hard hatch covers obviously cannot bulge or suck in, but they can become almost impossible to remove. On a hot day, these too hiss loudly when I open them. I recently drilled 1/16" holes in the center of the wood-fiberglass-epoxy BH’s. The cockpit is not likely to fill up with enough water to reach these holes. The amount of water I get in the cockpit from repeated rolling and sculling isn’t even close to that height.

Anyway, I’d rather get a little water in the hatch compartments than risk blowing out a BH.

For foam bulkheads…
…I poke a wire through them (a bicycle spoke), then insert a piece of plastic tubing (like the type that comes with spray lubes and cleaners) to keep the hole open.

Water in the rear compartment.
I doubt you are getting water in the compartment because of a pin hole in the center of a bulkhead. I have 5 boats with drilled bulkheads and often roll a lot and never get a drop of water in the compartments.

I’ll bet it’s your hatch covers if you don’t have VCP’s or Kayak sports, or your toggle hole area. Tape over your breather hole next time you roll practice.

You can drill a solid bulkhead with the tiniest finish nail you can put in a drill.