Replacing the Companionway Sliding Hatch

While we all try to avoid stepping on the Companionway hatch, at some time or another we end up stepping on it.  I have done this inadvertently a few times in the past, but I always tried to take care not to put to much force on it.  Well in August 2018, during a rush job of putting on the mainsail cover, I stepped on and cracked the top acrylic hatch.   It was initially a small crack, but after push and playing with it, the crack grew somewhat longer.   In the same rush a temporarily kludged fix was done using foil tape to "mend" and seal the long crack.  It stayed this way for about a month while I thought of ways to replace the acrylic, explored types of acrylics and alternatives,  estimated the costs, and finally found the motivation to just replace it.    

Original sliding hatch was constructed from 3/8" smoked
acrylic.  

Material Choice

I had every intention of purchasing a piece of  3/8" x 28" x 36" Transparent Grey Smoked Plexiglass. The cost for this material was reasonable cheap (on the order of  $100 plus shipping).  Instead,  I used a piece of clear 3/8" acrylic which was given to me some time back.  The problem with the acrylic (and the reason it was free) was that the protective paper was old, dried out, and did not easily peel off.  A trick I came across many years ago, was to soak the protective paper with isopropyl alcohol.  I found that placing and soaking paper towels on top of the protective paper allowed for a good solid soaking.  A plastic sheet (split open Hefty) was used to keep the alcohol from evaporating too quickly.   After about 30 minutes or so the protective paper would come off with little effort.


Removal and installation of a temporary sliding hatch

A temporary sliding hatch was constructed from 1/4"
exterior plywood.  A small 1"x2" wood strip was
added ,in a similar fashion to the original slider, to
which the locking hasp was attached.   

Since the old hatch was needed to pattern a replacement, a simple temporary sliding hatch was fabricated out of plywood and a 1" x 3" board.   This rather simple design functioned quite well as a sliding hatch.  Even a lock hasp was installed so that the hatch could be locked using the original locking set up.

The removal of the sliding hatch requires removal of the backstay traveler cross bar.  After its removal and removal of the hatch cover screws, the hatch cover simply lifts out and the sliding hatch is free to remove.

Cracked slider with temporary taped repair. The
side Aluminum angle rails, teak top handle, teak
bottom board, and teak slide stop have been
removed.

Fabrication

Clear 3/8" acrylic was sanded on both top and bottom faces to
provide a frosted appearance.

A table saw was used to cut the acrylic to the width and overall length matching the original hatch dimensions.   The original hatch used long aluminum L-bracket for sliding on top of the frame of the companionway.  Each bracket was held on with 6 flat head machine screws with thin hex nuts on top.  The old brackets were removed and the bolt holes were  transferred to the new acrylic.  VERY IMPORTANT!  Use plastic drill bits to drill the holes in acrylic or you will most/very likely crack the acrylic.  After drilling the matching holes, the L-brackets were reattached using a little marine sealant (butyl would be better) and the two surfaces of the acrylic were lightly sanded with 320 grit paper to create a frosted look.  The teak top strip and bottom  teak brace were reinstalled as it was on the original hatch.  Not seen in any of the photos is the back stop block.  The stopping block is a teak strip attached on the underside at the back end of the hatch.  It is attached to the acrylic using flat head wood screws.  A saber saw was used to round the front corners.  And finally, all edges were rounded smooth using an orbital sander.

Dry fit of sliding hatch components.  The teak bottom board is
secured to the acrylic by 5 flathead screws flush to the acrylic
surface.  These flathead  screws are covered by the teak slide
handle with an additional 3 screws securing the handle to the
bottom board.

New sliding hatch installed.

Final installation

The final installation was simply the reverse of the removal.  While the original intention was to use a piece of transparent smoked acrylic, the clear/frosted design looks smart-fully pleasing. In the end, the cost was under a few dollars as all of the materials were laying around save for a few stainless steel machine screws and nuts.