Davin,

If you're using invisible hold downs (bungee cords), you may want to reconsider putting the finger pull on the centerline. When the cords are properly tightened to hold the hatch cover on, it takes a fair bit of leverage to get the cover up with one finger. If you lift from a side you're only fighting one cord and get more leverage to do so. From the centerline you're fighting both with reduced leverage.

As far as minimizing pooling, it's gonna happen, no matter what. You just need to accept it and make sure that all the exposed surfaces are well sealed with epoxy.

Finally, I used a Dremel with a sanding drum to make mine, but a rasp of the proper shape will also work very well.

Laszlo

   Precisely the info i was looking for, thank you Laszlo!  Did install the blocks for the shock cord in the hull already, I wonder if i can arrange the lines to minimize the leverage issue. I have only a minor defect id like to hide, so off center is still an option.... thanks for the input!

   Precisely the info i was looking for, thank you Laszlo!  Did install the blocks for the shock cord in the hull already, I wonder if i can arrange the lines to minimize the leverage issue. I have only a minor defect id like to hide, so off center is still an option.... thanks for the input!

I installed the blocks 15 years ago :-)

This is the right front block (front of boat to the left). I made my system from scratch. Here's the bits:

The thing is, you really need a lot of downward pressure to compress the foam and seal the hatch, so you can't leave the bungees loose. If it's easy to open, it'll open at the wrong time (like when a wave or wake hits it).

For more info, check out my Building a Wood Duck 12 web pages. Pages 9 & 10 have details about the hatch.

Laszlo

   Got it, thanks Laszlo! Your site has been very helpful!

   Adding a thought on the invisible hatches.  For my kayaks I made my own bits and pieces much like Laszlo.  Wood blocks and wood hooks.  In one case the hooks were cut right into an additional athwarthisps strongback glued under the hatch.  Like Laszlo, I found this added sitffener necessary to hold the hatch shape (curved on my Chess 17). 

This design is based on the theory (fact) that the longer the piece of bungee used to do the hold-down, the longer/smoother action force you'll get for any given level of tension the bungee can supply.  As total length gets shorter, a piece of bungee can go from zero tension to "too much" tension within just an inch or two of length of pull (additional stretch).  With a short bungee, having sufficient tension on the closed lid means that it might take significant force to lift the edge more than a couple of inches as needed to reach under to pop the bungee loop off of the hatch-bottom hook.  My effort to increase bungee length was accomplished by putting the hull-attached blocks down low, right in the hull bottom-to-hull side corner.  Each bock has two nicely smoothed holes, with filed-out curved entry corners.  The bungee is then run as one continuous loop. 

To explain this without pictures: Imagine starting the end of the bungee at the bottom centerline of the hull, go starboard along the bottom of the hull, up through one hole in the starboard block, then up around the starboard hook on the bottom of the hatch, back down through the other hole in the starboard block, then to port across the bottom of the hull, up through port block, up around port hatch hook, down through port block again just as was done on starboard side.  Now you're back to the middle of the bottom of the hull and ready to cut to length and join up with the other end of the bungee, forming a continuous loop.  You can use any type knot or easy adjustment type device you desire to form the loop.  Leave things long in the beginning until your desired tension is achieved through testing the hold-down power.  Changing bungee strength (mostly determined by diameter) can help with fine tuning.  You can make a good guess at which bungee size to use by forming a loop of about the same length that will be used on the boat and giving it some test pulls.  A nice firm pull with about 4 inches of stretch will do. I'm just guessing, but maybe about 10 lbs force when pre-stretched to the "closed hatch" length, building to something like 20 lbs when stretched 4 more inches to the "reach in under the hatch" length. I can't really describe how to make the choice, but you'll know what feels right.

With this set up, as soon as you get your fingers under the hatch and pop one loop off of the hold-down hook, the whole hatch is instantly free/slack, no force still being applied by the othe side, which is also nice.  There is naturally some concern over interference from cargo placed in the hold interfering with the bungee.  In my set up the bungee is only about 1 inch from the bottom of the hull.  I've found that I can just lay things on top of the bungee with no concerns or problems - if something big and heavy and bulky is on the bungee, the hold-down force might be only slightly increased.  Maybe it helps keep things from rattling around, as an added benefit!

Many ways to skin this cat, but this set up has worked well for me.  Bubblehead.

Bubblehead wrote: There is naturally some concern over interference from cargo placed in the hold interfering with the bungee.

That is exactly why my hardware is placed the way it is. I wanted to maximize the clear volume so I could carry bulky, yet light, items such as collapsible wheels, a lunch box, etc.

If your cargo will fit with the longer bungees I can't think of any disadvantages to Bubblehead's setup.

Another thing to keep in mind is that the hybrid has a different shape than the S&G deck.

Laszlo

   Thanks for the input, bubblehead!