Day 7

5-12-2012

The task for today is one that I have been torturing myself over from the first day I began.  It's time to cut a large hole in the deck of my boat.  Not only do I have to cut a hole, but the piece that I am going to be cutting out if going to remain as a part of the boat so it is incredibly important that this be done neatly!  There are no do overs for this task, this is permanent.

The Wood Duck 12 has one permanent bulkhead located behind the cockpit.  If the boat is constructed properly that bulkhead forms a water tight compartment in the stern which is the perfect place to store gear when on the water.  The stock hatch on the Wood Duck 12 matches the grain of the deck since that is where it is cut from, and it rests flush on the deck when in place giving the boat a very sleek look.  The hatch assembly consists of the hatch cover (cut from the deck), a hatch stiffener which is an oval piece of plywood glued to the underside of the hatch cover, a hatch sill which the hatch cover sits on, a hatch spacer which is glued between the sill and the deck, and a hatch rim which helps keep water out of the compartment.

The inside of the hatch spacer is used to trace the opening.  The deck has four 1/16" holes drilled in it which line up with four holes in the hatch spacer so you can be sure you are putting it in the right place.  I used four thumbtacks rather than copper stitches to align the spacer.


Next I had to cut out the hatch.  I have never been very good with a jig saw, they always seem to get away from me and I end up with jagged cuts that are never straight.  For this reason I purchased a new tool solely for this purpose called a Bonsai saw.  As the name implies the Bonsai saw comes from Japan and was originally designed for cutting, yes you guessed, Bonsai trees.  It is a small hand saw with double rows of sharp teeth which cut on the pull stroke and create very neat cuts with a minimal kerf.  To start the cut I used a utility knife, pushing down while rocking back and forth so the blade sliced through the wood until the tip pieced the inside of the deck.

Next I slipped the Bonsai saw into the opening made by the utility knife and slowly began cutting along the line.

Cutting the hatch by hand takes a while.  I would pull a few strokes, blow away the saw dust so I could see my line, then continue cutting.  

One note about using a Bonsai saw which I wish I had learned sooner.  The Bonsai saw will make a much cleaner cut and will not pull at the top grain of the wood if the cutting angle is at least 45 degrees or less.  Using the saw at a 90 degree angle ensures that the teeth will pull at the veneer and you end up with torn edges around the cut, especially when cutting across the grain.

This is wrong:
This is right:

I should be able to sand away most of the damaged grain, I just wish I had known this little tidbit sooner.

Once I had 90% of the cut completed I wanted to ensure that the hatch cover didn't fall into the boat before I had cut all the way around.  I used two putty knives to support the wood opposite of where I was cutting and was able to get the rest of the way through with no tearing or breaking.

Once the hatch was cut out I mixed up some epoxy with silica powder to a mustard consistency and applied it to both the stiffener and the hatch cover.  These need to cure completely flat so I used some 2x4 scraps and a heavy bucket to press down on them.

Next I applied the same epoxy and silica combination to the hatch sill and spacer and clamped them into the hatch opening.  It pays to be neat here because this area will be difficult to sand later, so I used my putty knife to scrape out as much excess epoxy as I could once the clamps were in place.


Once this cures overnight I still need to install the hatch rim.

Total time on this phase: 1.5 hrs. 
Total time on construction: 18.0 hours
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