Boat Building Forum

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Magnetic Hatch construction *PIC*

Has anybody done a magnetic hatch in a glass (not wood core) boat? All-glass laminates are much more flexible than cored layups.

Has anybody done a magnetic hatch in a peaked deck?

Consensus on the best seal type? I'm thinking of the 'ridge in the lid pressing into a foam gasket' style.

Ideas about optimum hatch opening size and shape? Ledge/sealing area width?

Compass interference is a concern; comments?

John, your timing is impeccable.

I've just uploaded a video on Youtube on making my magnetic hatches.

The design I show has evolved over twenty years. The placement and size of magnets, the width of the deck lip, the raised edge on the deck lip, which presses into the gasket placed inside of the magnet ring, and the side drains, all working together, create a waterproof system which works.

It is critical to ensure the magnets are perfectly sealed under a layer of glass or veneer and that all edges are coated and water proof. The black epoxy coated "waterproof" magnets sold by K&J Magnets are advertised as waterproof but I had a customer who damaged a hatch cover and had these magnets corrode and had to be replaced. When I confronted K&J they said the waterproof claim was a mistake and they changed the text on their site. I see they are now back to claiming these epoxy coated magnets are waterproof.

I still use these epoxy coated 3/4" x 1/8" magnets, but I make very certain I seal them under a layer of glass, veneer and epoxy.

The magnets are very strong and can distort a stripper hatch cover if poles are not aligned correctly.

I'm certain if they are used on a more flexible fiberglass hatch cover they will pull it into the deck lip even more.

The magnetic field drops off quickly and does not effect a deck compass placed 16" away.

Please let me know how I may be of further assistance.

All the best,
Rob Macks
Laughing Loon Custom Canoes & Kayaks

I hear and I forget. I see and I remember. I do and I understand.