Hatches with magnets

Latest updated Monday, October 24, 2022, 2 comments

Making these hatches proved to be really time-consuming! Wow, I think I have easily spent 20 extra hours in the shop. But seeing the result it was absolutely worth it. Besides the good looks, I have more space under the deck because there are no recesses, and closing the day hatch in waves is really easy – the magnets always end up in the right position, on top of each other.

This way I can close the day hatch with one hand without even looking/turning around… nice bonus.

I have followed Rob Macks’ method. I stumbled upon nice tutorials from his company Laughing Loon on youtube, and eventually purchased an instructional dvd on hatch making.

Key things I found out while working on the hatches:

Choosing wood for the spacers and lips that is soft enough to bend.
When covering the deck magnet rings in graphite, I taped the foredeck ring to the concave deck to let the epoxied carbon mat harden with the curve.
Rob Macks uses a thin veneer to cover the magnets in the deck lip.
Work the magnets in the holes in the deck lips/hatch rings as tight as possible, and make sure they are perfectly sealed against moisture

Construction:

Mark the polarity of every magnet to prevent mistakes.
I rounded the underdeck outside edges of the magnet rings and spacers before coating them in three layers of epoxy, to minimize hang-ups with stowing gear in the hatches.
Get the right size and holding power for the magnets! Mine were 18x3mm, holding-power of 3.1kg.
For the inner lip edges, that are pulled into the rubber seal, I used very straight-grained yellow cedar (bowwood). This was easy to bend using a heat gun.
These inner lip edges need to have a constant height to ensure an even positive press into the hatch seal rubbers
For the seal rubbers, I am still on the lookout for the perfect, one-piece solution. At the moment I have a 3mm closed cell HDPE tape, 1cm wide. This tape shrinks a bit when wet, leaving a tiny gap. My hatches are almost dry when touring, but an hour of rolling gives some water ingress. I am planning to cut closed rings out of sheet rubber or neoprene, but sourcing the right hardness takes some time.

Comments

1 Davide Turelli
11/10/2022 8:21 AM

I am very happy to hear that someone is satisfied with magnets on the kayak. Unfortunally i am not.

I have built two kayaks using magnets on the hatches, and, a couple of year later for the first one and some months later for the second one i had to remove them all, rebuilding all hatches. They started to show some rust spots here and there under the resin.

May be the first attempt was not made with the right attention and carefulness and some air bubbles remained embeded into the resin and the umidithy let the magnets rust... it is possible.

The second attempt was made really carefully, using a vacuum pump to avoid air stagnation into the resin and all surfacies were covered with carbon fiber... some risults. Some month of salt water let the magnets to show some rust spots ( a few indeed, but too much for me).

I gave the magnets a second chance, but i won't give them the third.

2 Dan Caouette (CSCWC)
11/10/2022 6:45 PM

Throughout the past nearly 20 years of building kayaks, I have installed magnetic hatches on a total of two projects. I agree with Davide. They are very labor intensive and personally not worth my effort. While the simplicity and clean appearance is attractive, the short and long-term performance was seriously lacking from my experience.

My standard hatch systems are commercial units that use either deck plates or rubber hatch lids with plastic lips. These are set into recesses in the deck. The labor creating the recess is offset by the simplicity of the system. Once the kayak is clear coated, the lip is simply glued to the recess and the lid can be snapped or spun on. While the commercial systems cost extra and weigh more, they are watertight and reliable. The lids can also be easily replaced if lost.

If a customer wants wooden hatch lids then I use either internal or external bungee cords.

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