Several listees felt my idea of a hardtop (roof )of fiberglass covered light
plywood would be too heavy. Sides would be roll up roll down sunbrella &
windows. Honeycomb cell products were suggested instead.
(1) Did my use of the word "hardtop" in my original post cause visions of a
complete enclosure, including sides?
(2) Would a cored product roof covered with glass differ much in weight from
maybe 20 lbs of plywood covered with glass? (Another 50 or even 100 lbs atop
my 25 ton boat is less than a guest sitting on the flybridge anyway.) Am I
missing something?
(3) How does one fasten/construct durable edges with a cored cell roof top,
say an inch thick and two inches high. This would be used to fasten to my
radar arch at the back, provide a drip edge, and keep rain from getting
between the sidecovers and the roof.
Thanks,
Rob BRueckner
'71 Hatteras Yachtfish.

<<How does one fasten/construct durable edges with a cored cell
roof top,
say an inch thick and two inches high. This would be used to
fasten to my
radar arch at the back, provide a drip edge, and keep rain from
getting
between the sidecovers and the roof.>>

I've used two different methods of edging a cored pilothouse
hardtop.  Home Depot sells baseboard and various trim made of an
expanded plastic material (PVC?), sort of a fake wood.  This
material adheres well with epoxy, and is moderately strong, but
not very stiff (easy to bend).  The trim I used was only 1/4"
thick, and did not extend up above the top surface of the hardtop
(no drip-edge).

For an extended rain-catcher or drip-edge, use a high-density
(5-7 lb/cu ft) PVC foam, sawed to the height and thickness you
choose.  On Pooh, this edge is about 1.5" thick and extends 2"
above the hardtop top surface.  Epoxy the edge all around the
top, then use a rounding bit in your router to make everything
smooth and round before glassing over the edge foam.  You may
want to use solid wood or fiberglass inserts where the radar-arch
or other structure will attach to the hardtop; sandwich
structures do not take point loads very well.

=====
Mark Richter, M.E., aboard M/V Winnie the Pooh,
custom Morgan 46 Pilothouse Efficiency Trawler.
"Mark's Mobile Marine" electrical systems repair & consulting.  Homeport Stuart, FL

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