> Hi, I have been reading this list for a short while now and will soon
> start building a Queen Charlotte 17. I have read many diatribes on flush
> mounted hatches and fittings, it seems like everyone has a different
> method of holding the hatches down and there doesn't seem to be a
> consensus on which is the best way. So I had this idea of my own that
> might work and that would be cheap and easy if it did. If anyone has any
> constructive criticism I would welcome it. Lee Valley sells some pretty
> amazing rare earth magnets. I know it sounds far fetched, but their
> biggest one, an inch in diameter and very thin will lift 35 pounds. With
> their new "concentrating cup thingys" the force is increased
> fourfold. A few of these would seem to hold down a hatch adequately, in
> fact might make them hard to get off! Has anyone ever tried this? My other
> idea was to use those surfboard leash attachment point things sunk in the
> deck for bungy attachment points. they are little cups with a bar across
> them. I don't know what they are worth, or whether they would be suitable
> but they might be ok. Paul L

I have used channelled magnets (the magnet is surrounded by soft iron plates to increase the ``pull'') for holding up plywood wall panels. I was able to interchange the panels with just a good STRONG pull. To do this I mounted the magnets to a wood frame of firring strips. I them used construction adhesive (Liquid Nails brand, I think) to mount 2 1/2 inch diameter fender washers to the back of the plywood panels. It was not too hard to align them so they were directly in front of the magnets.

Problems with use on kayaks: You need to use iron or steel, which will build up a layer of rust on constant exposure to water. Sure, you can paint it, but the layer of paint makes the bonding of the magnet a bit weaker. Rust can form under the paint, changing the surface from a smooth one (high `pull') to a rough one (lower `pull').

The magnets are physically large and will block some of the hatch opening. You can counter this with a larger hatch, but then you may need another magnet or two. Draw out your plan full size on a piece of cardboard and see if you can achieve a good compromise on hatch opening vs. number of magnets before you cut any holes in the deck.

The extremely powerful magnets I've gotten (loudspeaker surplus) show a definite effect (BAD) on my TV screen when they are anywhere within 3 feet of the TV set. I got one magnet near a computer monitor and it really messed things up. Be careful with handling them around electronic stuff. For that matter, a strong magnet will definitely affect the accuracy of any magnetic compass that is near it. It will be more expensive, but you may want to consider using a GPS system to help you find your way.

You can get the magnetic sealing strip from refrigerator doors at appliance repair and parts stores -- or you can buy it direct from Sears nationwide parts service. Call them up and give them the model number of YOUR refrigerator at home and they'll quote you a price for the magnetic gasket material. If you use strong magnets to keep the hatches on, you can use this material to seal around all the edges to help keep out the water. By themselves, though, they probably aren't strong enough to do the job.

Be sure to include a tether on that hatch cover. A sharp blow (hitting a rock, a crashing wave, etc.) could jar things loose.

You may want to make a couple spare hatchcovers when you make the first ones. This is certainly not the usual way to attach a hatch, so assume there may be some experimenting to do, and you may lose a hatch or two during the experiments. Plan ahead.

Best of luck with this if you decide to pursue it. If it works, send some pictures. If it doesn't, let us know that, too.

Paul Jacobson