However, apart from being decorative, their main purpose
protect and seal the edges of the deck covering.
They can also be used to good effect around deck openings such
as cabin trunks
Why Fit Covering Boards?
There are several different methods and
reasons for fitting cover boards.
While the basic concept is the same, how you go about it will depend on
Covering boards are an essential part of fitting a laid deck.
They are also used to frame and seal the edges of fabric covered decks.
Plywood decks can also benefit from being framed by cover boards.
The boards are made up of several shorter planks scarffed together to
continuous edge to the deck.
As a rule they lie on the sheer-strake and are usually the same
the rest of the deck.
The covering board is also the place where all those stanchions and
are sited. It is particularly important to keep the joints between the
board the deck material and hull planking, frames etc watertight.
This will be aided by
caulking cotton in a
V shaped track between mating surfaces.
It is essential that
the edge of the deck and cover board are supported by either a batten
into the carline or by blocking between the beams.
In order to get the support in
the correct place your
first task will be to mark on the beams the position of the join
cover board and the deck.
Use a springy fairing batten
tacked to the beams with
small nails allowing the batten to springs fair.
Blocking will provide better
support for the cover board
scarfs and deck plank nib ends.
If using a ribband this will
need to be wide enough the
support the nib ends of the covering board scarf and the deck planks if
a planked deck.
The tops of the beams,
breasthook, anywhere where the
cover board is to sit will need to be planed flat so covering board
Due to the curvature
of the hull cutting the
covering boards from one piece would be very wasteful of wood.
So they are normally made up
from short lengths scarfed
Cutting the scarfs will
require some skill and
You will probably have to make
adjustments to the scarphs
to get them to fit tightly.
So, always leave
outer edges of the boards until all the scarfs are cut
To facilitate the cutting of
the scarfs make up plywood
patterns for both sides.
Or make a jig so that they can
be cut using a router,
this will save a lot of time as well as producing accurate joints.
The inside corners can be
cleaned up with a sharp
Once all the scarfs are cut
fasten the boards in place
and then mark out the inner and outer edges using the spiling
To ensure that the nibs remain
watertight, drill into the
edge of the nib joints and fit softwood
The sections used to make up
the covering board could be
While a butt joint is the
easier than scarfing it
won't look as good and will need more fastenings to ensure it secure
and keep it watertight.
Transom and Bow Corners.
Not only is it
to run the cover board
across the transom it is also very pleasing to the eye.
It is possible to join the
transom cover board to the
side board with a simple miter joint.
However, you do not want any
sharp ends to extend to the
Even the best of us can
occasionally catch that back
corner when leaving a dock.
It is better practice to make
the corner from a separate
And this will allow you to
create a more pleasing radius
to the inside of the corner.
Don't forget that the transom
board will also need
support blocking to prevent the decking and covering board from
The joint at the bow can also
be made by setting in a
separate corner piece.
There are two main styles of laid
deck the sprung plank and the straight
The sprung deck, without doubt
is the better looking
however, the straight laid deck can look pretty fine too.
With both types the plank ends
will need to be nibbed to
avoid having vulnerable sharp corners.
Sharp points are particularly
vulnerable when caulking.
The sprung deck will need
nibbing where the planks end at
fore and aft elements such as the king plank or cabin sides.
The straight laid deck will
need to be nibbed where the
plank ends meet the cover board.
Some builders use a margin or
nib plank set inside the
The nibs are then cut into the
margin plank rather than
the cover board.
However, nibbing is only
needed on the sharper plank
ends, where the angle is less than about 20 degrees.
It is probably best to cut
each nib and mark and cut the
covering board or king plank as you lay each plank.
A really smart way of dealing
with the openings in a laid
deck is to frame them with cover boards.
It does mean that you will
need blocking or a carline
underneath to carry the plank edges.
However where the sides of the
opening run fore and aft
and have little curvature this may not be needed.
Canvas covered decks.
Canvas covered decks are something of a
rarity theses days.
It used to be quite a common
method for sealing planked
decks on small boats.
The primary purpose of the
cover board on a canvassed
deck was to seal and secure the edges of the canvas.
Though in some cases a
hardwood spline was used to trap
the edge of the fabric into a rabbet either in the covering board or in
deck with the cover boards fitted against the spline.
The idea of the spline was
that it was easier to remove,
if the canvas needed repair than removing the whole cover board.
The deck edge covering boards
should be either flush with
the deck or slightly below the deck level to allow water to drain away
and not be allowed to settle along the plank edge.
The king plank on the other
hand being at the high point
of the deck curvature could be set on top of the canvas.
Plywood covered decks.
The king plank
deck can also be set on
top of the joint between the panels.
Hollow the underneath of the
plank to allow plenty of
room for sealant.
Cover boards for a plywood
deck need to be organized to protect the end grain of the
The inside seam of a flush
fitted cover board is
particularly vulnerable to leaks, so particular care must be taken over
securing down and sealing of these edges.
If the deck is made up from
laminates of plywood the
covering boards can be set in line with the top laminate but on top of
their built in
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