: To get the same holding power using steel plates or washers, you'd need more
: pairs. For example, you might need 12 magnet/steel pairs to get the same
: attraction force as 8 magnet/magnet pairs (these numbers are assumptions,
: I don't know what the real numbers would be)

: So in the above example, you wind up drilling more holes in your lid (12
: instead of 8 ), and having to mess around with more fillets in the lip (12
: instead of 8 ). I can tell you that drilling those recesses in the lid to
: install the magnets was a hairy operation. Not difficult, just
: nerve-wracking. One slip and you could go right through. So why not
: achieve the same holding force, with less work? And less risk of screwing
: it up?

: Polarity does not have to be an issue, depending on your building method and
: sequence. It would be physically impossible to get the polarity reversed
: the way I'm assembling it. Therefore, no worries.

It is better to use magnet pairs because they will not only have a stronger pull,
but will automatically align the hatch cover to the deck lip and gasket every time.

With a magnet to steel plate set-up it will not align the same each time and will
narf up your gasket.

I know this from experience.

All the best,
Rob