: I would like to hear the discusion on this topic as well. I have both and
: can't decide a favorite!
: I used 3/4 " webbing with clip buckles common at fabric and out door
: stores.
: They hold well but they do tend to stretch when wet.So you have to check them
: every time.
: Bungies are good but I'm always worried that I'm going to pull off the wooden
: padeyes.
: For serious touring I like the neoprene cover under a hard hatch held with
: buckles. But that system seems complicated for a home made boat?
: Are your raised hatches like the ones described in Nicks Book?
: Terry
: PS I would like to try soft loop padeyes with bungie as the hold down but I
: have't figured out how to connect the bungie so you can get into the hatch
: easily,without using a hook.

I started off with webbing and fastex snaps on my kayaks about 1990.
At that time my solution to creating an air tight hatch was an raised lip
on the deck with a hatch cover that sat on top of the lip (where the gasket was placed)
and had an over hanging lip. This raised hatch cover allowed very good
downward pressure to be applied to the gasket and these hatches were air tight.

I did find adjustment and closing the fastex buckles on the webbing cumbersome,
so I switched to a four point shock cord hold down system. The shock cord was held
with two permanent connections (pad eyes) at one end of the hatch and two hooks at
the other end to allow the shock cord to hold or release the hatch cover. This worked
well because the shock cord applies constant downward pressure and is easy to open
and close because of the natural stretch of the material.

Later I switched to a six point shock cord hold down arrangement with pad eyes in each
corner of the hatch cover and hooks in the center sides. This arrangement put more shock
cord passes over the hatch cover for more pressure to ensure an air tight gasket seal.

Then everyone decided they liked flush hatches. The problem with flush hatches is that
the hold down methods are attached to the deck surface and pressure from these straps or
shock cords is reduced toward zero the flatter the deck/hatch cover is.

Most of my kayak deck designs had a fairly high crown so the six point shock cord arrangement
continued to work well for my flush hathces.

To apply more downward pressure on a flat hatch cover, some people resort to placing ribs
on the hatch cover surface to run the straps or shock cord
up and over to increasing the downward pressure on the gaskets.

Others developed internal ribs/blocks and shock cord (Liddy lids) to pull down on the hatch
cover from inside to seal the gasket. This is nice because the hold downs were now invisible.

When some of my deck designs got flatter I was faced with solving the problem of low/no
pressure to seal hatch gaskets with deck hold downs/hardware.

The internal shock cord solution did not appeal to me. I was concerned about the complexity
and reliability of this system and the potential for gear storage to hang-up on it if the storage
compartments were tightly packed for long trips.

I wanted something very simple, very neat, and very reliable.

I developed the magnetic hatch hold down method in 2000.
I had some of the small rare earth magnets form Lee Valley Tool
which came with a tool I purchased from them. I was impressed with
the strength of these mightily mites.

While thinking about the flat deck hold down problem, I went into the frid
for a beer and as the frid door closed I thought "YES", beer is the answer,
NO! NO!, I mean magnets are the answer. The magnetic tape around the doors
of most refrigerators does a great job of sealing them, so why not on a hatch
cover.

The frig tape was no good but the rare earth magnets came to mind.

I gone through quite a few tests and arrangements and do the following;

You need a magnet to magnet contact for the strength needed to bridge the gap until your gasket compresses.
You must use a soft gasket material that compresses very well.
Soft gasket material is available from Newfound Woodworks or I also sell gasket material.

I use the 1/2" diameter X 1/8" thick magnets when the magnets have only one layer of 4 oz. glass over the top
the ensure waterproofness. I use 3/4" X 1/8" magnets when I add a veneer over the lip magnets to hide them.

Rare earth magnets available from Lee Valley Tool; http://www.LeeValley.com/

The magnets are recessed into the hatch cover and hatch lip on the deck. I use eight on the hatch cover and
eight on the hatch lip. A total of 16 per hatch. This may sound like a lot but I did extensive research and
found the number and configuration I'm describing works the best. 4 per side spaced about 3' apart.

The magnets rust if not totally sealed, so I cover them with a layer of 4 oz. glass.

Aligning the mating pairs is important. MAKE SURE THE POLES ARE ALIGNED SO THE MAGNETS ATTRACT, NOT REPEL!

You MUST BE WARE the magnets will effect any compass placed in proximity.

I found the magnets effected my compass if it came within 18” of the hatch cover.

I currently use 3/4" X 1/8" magnets and add a veneer over the lip magnets to hide them, with
the magnets visible on the hatch cover as shown in the picture below.

This makes an air tight seal even with flat decks/hatch covers. The force is very strong.
enough so I carry a wooden pry bar to remove the covers when a temperature change
creates a vacuum in the compartment.

All the best,
Rob Macks
Laughing Loon CC&K
www.laughingloon.com