By Robert Ditterich - Geelong, Victoria - Australia

To Part One
To Part Two
To Part Three

A Pictorial Essay of a Navigator Build

A close up of the top outer log attached to the side and the molding. Note the back triangle of the molding forms an epoxy fillet in that gap.
The top of the pic shows the bottom aft end of one of the CB case sides, attached already to the end log, the top outer side log, the bottom doublers, and in this case I've also attached a molding strip traditionally called 'scotia' in Australia. I've done this mainly for aesthetic reasons, but it also adds better strength than an epoxy fillet (I think)
2 long f clamps pull the case firm against the keelson, and are helpful to 'nuance' the verticality of the unit. The other clamps are there because the interior of the case has just had its third coat of epoxy ('glass fibre under the first two coats) and the sides glued together. The whole unit was then clamped and temp screwed then lowered into the hole in the keelson.
The bottom huge fillet called for in the plans has been replaced here with a larger scotia molding, again with the back triangle behind it forming an epoxy fillet of normal size behind the wood. Because the floor is curved (concave) this molding has been pulled downwards in the middle with ply and temporary screws. The piece is backed by about 120ml of epoxy plus 403 filler to make a very thick epoxy.
The case is still open from the top. The top log will be attached to the case cap board, and will be screwed in position but removable for maintenance/inspection.
Note that B3 here is facing the wrong way! The 20 x 20 strip along the plywood top will face forward. (Cobbled together hurriedly for the photo.)
These bulkheads are just having their bases cut to fit the stringer and keelson before being given their first coat of epoxy.
Bulkhead 8 has a beam that links the two sides of the cockpit at the forward end of the rear seat, so the space under and behind this bulkhead is a good and accessible storage space.
B1 shown here has a 20 x 20 beam glued across the face as shown in the plans. This is part of the support structure for an anchor well that will be accessible from on deck. It is supposed to drain from a limber hole at floor height, out through the hull. Looking at other people's builds many seem to choose a higher floor for the anchor locker. Either the plans are wrong again, or there has been some serious deviation going does seem rather low...
Attaching these cockpit bulkheads needs to be approached with some care because the cockpit seat front can be distorted from the vertical- and needs to be checked at each bulkhead- because the verticality of this panel will impact upon the total width of the bulkheads, and therefore the trueness of the stringer lines.
For prospective builders - this piece has quite a different shape from the one in the plans...nothing to do with structure, though, just a shape I liked.
These stringers take seating ply on a slope upwards to B3. I've cut angled housing joints in the 20mm bulkhead top doubler to give a joint with good surface area for minimum cost to the strength of the bulkhead.
Wobbly, unsupported B3, two stringers with sweeping curves, and a few other things being glued at the same time. Keeping the bulkhead vertical while all this was happening called for the old 'clamp-the-spirit-level-to-the-work-so-you-don't-have-to-let-go-of-something-to-check-it' trick.
The 20 x 20 stringers that go along the CB case swing up to B3 in a curve, or at least mine do because I fitted them in one piece instead of having a join at B5. Surfaces here are very grotty and in differing stages of prep for epoxy coating. This is what I'd call an 'ugly shot'...
Managed to use a forstener bit to drill an oversized hole through the ply, carefully stopping right on the inside surface of the 3 epoxy layers. Left those in place to enable me to fill the hole with thickened epoxy without having to mask inside, or to have any unprotected wood remaining.
The hole is first smeared in unthickened epoxy and allowed to penetrate the grain, then very thick goop was pushed in, slightly over filling the hole. The next step will be to drill a correct sized hole that will have a ring of hard epoxy as a bearing surface.
Here the epoxy filled CB pin hole is drilled to fit the pin, leaving a bush of epoxy protecting the wood and providing a good bearing surface. It is difficult to align these two holes perfectly, and I'll have to introduce a bit more epoxy while fitting the pin (smeared with a release agent) .
...difficult to illustrate well, but here I'm using a couple of sticks clamped to the stringers to lever the stringers around to the vertical position so that they lie flat on the stem. These sticks are drawn together with shock cord and held with a clamp. I find this is preferable to achieving the same thing by screwing the stringer at the end, which is vulnerable to splitting. I did use a screw on each side, into a pre-drilled hole, but only after checking the verticality of the stem with a level. These 2 screws were just to finesse the verticality, rather than holding the stringer flat.
The first two pairs of stringers went in without any dramas. The rebates already cut in the stem needed nuancing a little so that the slot tilted downwards a bit - easily achieved with handsaw and chisel. The angle on the leading edge of the stringer was easily scribed by running a pencil along the stem itself, marking a line parallel to the notch a little in front of the stem. This extra length caused by the thickness of the flat carpenter's pencil proved to be about right for good length when the stringer was tucked into its slot.
Before the stringers were fitted, the bottom panel, cockpit seat fronts and some of the bulkheads were given a coat of epoxy, and some of the corners gained a fillet. It's good to give some sealing coverage to these bits while they are still easy to see and reach. The fillets were certainly easier to do while standing outside the hull than they would have been squatting down inside, trying to see under dark edges. These fillets are a combination of wood flour from the orbital sander and West 411 filler.
Decided to fit dry fit the ply for the seats before putting the gunwales on. Easier to get at it all, but they won't be installed for a while.
This is a very easily and quickly made tool that will enable you to draw a line on a surface to match a line which is below an oversized sheet, and therefore not visible. In this case, oversized ply is laid where the cockpit seats will be, over the curved vertical seat fronts. It was handy to know where those seatfronts were relative to the overhang while drawing the new edge. This photo shows the tool from underneath. It has been shaped so that the end of the bottom fork will touch the form that will dictate the position of the pencil, above. It could equally be made to draw a line a given distance in or out from the edge.
The tool is just a 75 x 19 off-cut about 180 long, with a pair of saw cuts inside to make it into a two pronged fork. The pencil is fitted into a tight hole and the bottom fork trimmed and shaped to give the correct length. Time to make this? About 4 minutes.
Because I want to keep moisture out of these lockers/buoyancy compartments, I've decided to put the mast step at seat level, rather than on the keelson. I could have encapsulated the bottom of the mast in a tube, drained to the cockpit, but preferred a simpler arrangement that will also make stepping the mast a tiny bit easier. The compression post is 33mm thick and is rebated into a 100 x 20 beam between B2 and B3, with 20 x 20 doublers under the outside edges. The step block will sit on the ply above all this.


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