I decided to install the mast step on the
keel, rather than engineer a deck step. Since I wasn't using an
existing spar, I didn't have to worry about the extra length required to
extend to the bilge, since I could just account for that when ordering a
mast later. A keel-stepped mast made the most sense for this
One of the
pitfalls of bilge-stepped masts is that the continuous presence of water,
or at least dampness, often wreaks havoc with the typical aluminum or
stainless steel mast steps. To counter this, I planned to build up
the step rather high above the bottom of the bilge. For strength,
and to prevent any possibility of corrosion (if metal) or
rot/deterioration (if wood), I chose to built the basis for the step out
of solid fiberglass, molded in place.
area in which the mast will step was narrow, and with the built-up step
there was the real chance of bilge water ending up trapped on the forward
side of the new structure with nowhere to go. Therefore, I had to
plan for limbers to pass beneath the new step. I would have used lengths
of PVC pipe, similar to what I did on the midships
bulkhead, but all I had around was the large 1-1/2" ID pipe,
which was too big for the application. Therefore, I improvised, and
decided to simply mold the limbers in place.
do this, I cut some strips of foam into 1" square rectangles, each
about 12" long, and rounded over the corners with some sandpaper to
make roughly circular profiles. I glued these in place at the
corners of the bilge in way of the mast step. The point of this
exercise was to basically mold the limber openings around the foam; when
all is said and done, the foam would be removed, leaving only the 1"
diameter openings passing beneath the outer edges of the new mast step
some thickened epoxy, I filled in the gaps on the outer and inner edges of
the foam, and then cut several layers of 24 oz. biaxial fabric to fit the
trapezoidal shape between the foam, over about 7" of its length (the
length of my built-up step area). I wet out a number of layers of
the material and rolled them out in place between the foam. I let
this cure overnight.
the next couple days, I added layers of fiberglass to the area until the
center step area was built up nearly to the tops of the foam limber
forms. Then, I made some thickened epoxy fillets as needed, and
laminated some wider strips of biaxial fabric over the entire area and up
the hull several inches on each side, thereby beginning the encapsulation
of the foam.
the next couple weeks, I slowly built up the mast step base.
Once I had a solid base of fiberglass cloth, I used some epoxy filler to
smooth and begin to level the surface, eventually achieving a level
laminate from side to side across the foam limber molds. Then, I
applied more fiberglass over the entire area, and then began to work on leveling
the platform fore and aft. I did this by applying thinner strips of
fiberglass to the aft end, and filling in the area forward with fiberglass
and, eventually, more epoxy putty.
at last I had the platform level in both directions (I lost track of how
many layers), I applied four final layers of 24 oz. biaxial cloth over the
main platform, and then covered these with two additional overlapping
layers of 24 oz. biax, which I ran up the sides of the hull to tie
the glasswork complete, I ground the forward and after edges to begin to
smooth the rough edges. Then, I reamed out the Styrofoam molds in
the limbers on each side; this was fairly easy using a triangular file to
remove the bulk of the material, and then a dowel wrapped in sandpaper to
clean out the small remaining amount.
I smoothed the edges of the platform and limbers with epoxy putty for a
clean, finished appearance. After a final sanding, the platform was
ready for painting.
Many moons later, I prepared to install the
aluminum mast step provided by the mast builder. It was a
simple 3/8" aluminum plate to which were welded a pair of aluminum tabs
that approximated the inside shape of the spar section. First,
though, I used the step to locate the cutout in the coachroof above for
the mast to pass through.
the new step located in the correct place on the fiberglass base in the
bilge, I used a level and a straightedge as an extender to mark the
center point of the mast step on the overhead above, marking directly
plumb above the step centerline. I marked it both transversely and
longitudinally. Then, I drilled a small pilot hole from inside out
to mark the spot.
I used a piece of cardboard to trace the shape of the mast section,
which I then expanded by 1/2" all around to allow some leeway and room
for the spar to rake forward or aft. After cutting out the shape,
and locating the center point of the spar according to the mast step, I
used the drill to make a hole in the center, and placed the template
over the hole in the coachroof, using the drill bit as a guide.
After ensuring that the template was properly aligned, I traced the
outline, and then cut the opening with a jig saw.
the hole cut, I immediately made a measurement and then went outside to
compare the actual height inside the cabin to the extra length of the
new spar. I was thoroughly relieved to find that it was just as I
had expected, and that I had apparently measured correctly in the first
Next: final installation of the
mast step, and finishing off the mast partners. More about the
mast itself is at this link.
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