|Raise the deck
The deck needs to be raised to clear the engine. A curved and tapered
piece was glued on the forward frame. This was cut out of the scrap
saved from when the frame was originally cut out and yielded a very nice
final match in grain and curvature.
The top of taper curves were made by using another scrap piece
cut off from an adjoining frame and drawing the curve from the center
point to ~4" on each side. This
was then glued in place. The front was raised ~1.25", the rear
By tapering the raised portions, the sheer line does not
change. The engine deck merely gets more arched than the plans suggest.
The discontinuity in the "fairness" of the deck is disguised
by the cockpit openings and the seat backs. Do not worry about the frame
that was cut for engine installation at this time. Small tapered wedges
will be added after the hatch opening is framed out.
Hatch opening sides
The hatch sides are framed next. These pieces define the width of the
hatch opening. They run the entire length of the engine compartment. The
hatch sides are ~4" tall. The non-obvious point is that the sides
should not be plumb. They must be perpendicular to the deck, or even slanted
slightly, with the bottoms tapered inwards toward the engine. If they are
installed plumb, the hatch will not be able to open once the hinge is
attached, because the lower edge of the hatch will catch on the opening. (If
you are curious, mine were plumb and the hatch would not open! It did
get fixed and the fix is not noticeable.)
Corner blocks are used to reinforce the joint (triangular pieces shown
in the photo). Since all of the hatch and hatch framing joints are butt
joints, glue blocks provide the necessary strength and rigidity. This is
much easier than having to rabbet the corners or make a box or finger
Hatch opening ends
The hatch ends are sawn with the curve matching the nearest frame
(trace from the frame). Saw out both the hatch opening ends and the
hatch ends as a pair. Install the support blocking and then the hatch
opening ends. The blocking helps greatly in getting the pieces into
alignment as well as strengthening the joint. Set the rear hatch
end slightly higher than the frame. This will allow it to be planed down
to deck level during fairing.
Hatch outer frame
Now the hatch frame is made and fitted into place. I used scraps of
6mm (1/4") plywood to shim the hatch pieces away from the deck
opening. Cover the shims with tape to prevent them from getting glued in
place due to dribbles while decking. Screws are driven through the
hatch, shim and deck frame to hold the hatch in place. Place them angled
slightly upward so they are easily removed once the battens and deck are
The bottom of the hatch corners should be flush the bottom of the
frame. Corner support blocks are added underneath. These blocks will
bear the weight of the hatch and people climbing over it.
Installing these blocks prior to the hatch frame eases alignment and
makes assembly easier. Use tape on the blocks to prevent the hatch from
getting stuck to them due to dribbles.
I mounted the hatch sides first and then the fore and aft ends. The
inside corner was again reinforced with a corner block. The corner block
was simply glued in place after the initial butt joint had hardened. It
would have been in the way during initial assembly. The corner block is
partially seen as the small square near the orange clamp.
Tapers are added on top of the
deck frame pieces to match the height of the hatch opening frames.
Place marks on the cockpit opening to show the gap between the hatch
and the deck frame. You can use these marks later to set the saw guide
and the angle of the blade. A 6mm gap is not that much wider than the
saw blade (1/8" ~= 3mm).
Installing the battens
Lay out the battens to approximate
what is given in the plans. The battens are splayed to clear the
engine in the center. Once the layout looks good, cut the batten
notches and fit the battens. Cut the notches carefully as almost all of
the joints will be visible either from the rear cockpit, or when the
hatch is open. Note, the center frame piece that was cut out when the
engine was installed is not replaced. With enough battens and the
strength due to the curvature of the deck, it is not necessary. There is
no bounce in the final hatch, even with two of us stepping on it!
up the squeeze out and make nice fillets on the joints you can reach.
Don't worry about any in between the hatch and frame, that will get
sawed and sanded off later, when you cut out the hatch.
blocking was added to the forward deck framing to accommodate a future
ski pylon. A large block at the bottom spans the width of the hatch
opening. I small one at the top spans the center batten opening. These
should give enough rigidity when adding a pylon later.
If you carefully complete engine and shaft alignment
before deck framing you can skip this step!
The prop shaft flange finally came! When
it was time to align the engine to the shaft the engine angle was wrong.
The front of the engine was too high, and there was not enough downward
adjustment available in the engine mount!
front of the engine had to be lifted up with the hoist. Yes, it is
trapped in the deck, and the chains had to be run between the deck
battens, The mounts were removed and the engine bed mounting points were
drilled out and chiseled down 1.5". The mounts were
reinstalled and now everything lines up. It takes a lot of motion at the
front of the engine to move the back a little. The front engine mounts
have limited adjustment range and the rear have plenty.
Fair the deck frame and apply the decking to match the
rest of the boat. I started the plywood sheet for the decking on the
first straight batten. This placed it slightly off center but the seam
was now over blocking. In the end, this area needed some additional
fairing as it was slightly humped due to the upwards pull of the
plywood. The hump was well under 1/8" at its worst.