serene – 3, part 15

ow go in the gunwales, bulkheads and thwarts, which make the hull looks more “full fledged”… Indeed, those gunwales, bulkheads and thwarts would transform the hull into a structure, which is much more stiff. Gunwales are thin strips of wood, 1.5 x 3 cm in cross section. I cut all those wooden strips with my small Makita table saw, which is extremely helpful for a wide range of different jobs, especially because it cuts are flat and straight, unlike those made with a hand held jig saw.

The more I use it, the more I discover new techniques and tricks to get some jobs done. Also with the Makita table saw, I bevelled the gunwales, diagonal cuts at 45 degrees along the forward parts of the gunwales. I would adjust those bevelled edges along the boat length later, to better match the hull versus the deck. Now having a total of 32 clamps of different types, I’m able to install the two gunwales, port and starboard at the same time, not one after another like before.

There’re two bulkheads compartmentalizing the kayak into 3 sections, and 3 additional thwarts near the two ends that would help transforming all into a rigid structure. All is glued in places, then reinforced with small 4 cm screws connecting them to the gunwales. Then putty – fill the bulkheads to secure them to the hull, then a layer of glass over on the cockpit side since that’s where they could be potentially exposed to water. Still some more jobs need to be done to complete the hull!

serene – 3, part 14

urchased a new roll of 6 oz fiberglass, also “plain weave” like that was used in my previous boats. Surprisingly, the 2 kinds of fiberglass cloth, both 6 oz and plain weave, are not really the same, the later cloth has finer and denser fiber, it’s slightly heavier, a bit harder to wrap around and it absorbs more epoxy. It’s now time for some glassing, the hull receive a layer throughout its internal side, while the deck is only reinforced at places: around the forward hatch and around cockpit.

In my calculation, glassing adds, on the average, about 0.4 kg per square meter of surface (the glass mass itself plus the epoxy). So, glassing both inside and outside of the hull would add about 2 kg into the boat weight. That’s not really a big issue, as long as the glassing work is done properly, avoid using too much epoxy and keep weight in control. Sometimes, you need to step back and watch for everything you’d done during the past times. It seems that with 5 kayaks, all stitch & glue…

I’m becoming what they usually call: a prisoner of one own experiences, having designed and built several boats again and again using the same methods and techniques. While that’s somewhat true, in each boat, I’ve been trying to incorporate new things, new design ideas, new techniques, new accessories… My thirst for “the perfect kayak” has not been wholly quenched yet! And that “great journey” has not been done yet, lots of things waiting ahead to be full – filled, to be accomplished!

serene – 3, part 13

eck works continue… installing the anchor points, 12 for the 2 hatches, and another 12 for the lashing bungee cords, and additional 6 at various places along the deck, quite a lot of work. But there’re many other “unnamed” jobs related to the deck still: beveling the cockpit and hatches joints, glassing the cockpit joint, install the bulkhead… I also switch back and forth between the deck and the hull: glassing the hull’s internal seam lines, gluing the wooden blocks at bow and stern, etc…

First image: the anchor points to hold down the forward hatch, 6 pairs of 6 mm holes (both on port and starboard sides) are used to mount the 6 loops of 4 mm paracord, which in turn are used to secure the belt locks. Second image: various anchor points are placed along the deck, some used for the hatches, some used for bungee cords, and some are just “reserved”, those are not readily in use, but provided for lashing things down on to the deck should the need arise.

Third image: wooden block glued to the bow, later a hole would be drilled through to run the kayak’s pulling line. Fourth image: another wooden block glued at the stern, note the two 5 cm screws, to fasten and reinforce the rudder post (would be installed later). The rudder post is another wooden block glued on the external side of the stern, rudder, rudder post, rudder control lines and control pedals, and the “new” rudder box are important issues that would be covered in next posts.

serene – 3, part 12

ext came the hatch locks, each hatch is hold down by 3 belt – locks, similar to those usually found on your backpacks, very secured and easy to lock / unlock. But that would be later on, for now, the locks’ anchor points need to be built and installed. There are many of them (a total of 30), as the anchor points are not only used for holding the hatch lids down, but also for other lashing bungee cords, and they are built exactly as in my Serene – 1 & 2 previous kayaks, a tried and true technique.

A line would (from the external side), go though the “half – circle tunnel” drilled inside the wooden blocks and loop back to the external side of the hull, forming very strong holding points for various lashing lines. I made two MDF templates and cut the grooves with my very handy Bosch router (first image), a set of three anchor points is placed on one same wooden bar (second image), and install as a whole (fourth image) for the ease of installation, just gluing the wooden bars to the deck.

The deck doesn’t receive a layer of fiberglass throughout, it is only reinforced at critical positions: around the cockpit, around the hatches, or along the seam lines, to help keeping the final weight low. But for an “expeditional boat”, weight is not the primary concern, the boat need to have some “mass” to withstand considerable amount of abuse in long paddling trips. I would expect around 20 kg finally! It’s bad that I’d seen the hull flexing a bit under heavy loads with my Serene – 2 kayak!

serene – 3, part 11

ontinue working on hatches. First image: the completed two hatches (still without the gaskets inside) with the hatch rings (rounded rectangle in shape, cut from a sheet of MDF and strengthen with quite a lot of epoxy). Second image: the recessed (flush deck) forward hatch, the deck is cut 1 inch down, and about 45 cm along the length to get a wider space to install the hatch. This part of the deck is quite weak, and need to be reinforced with some putty and fiberglass inside.

The hatches’ size look a bit small, 18 x 38 cm internal (cut out) side, but that’s sufficient to let many things through, e.g: water bottles or the tent bag, most objects are of long and narrow shapes. I intentionally try to keep the hatch size small as possible, to help with waterproofness. Third image: gluing the forward hatch ring onto the deck, the recessed base is about 1 inch lower, so that when the nearby hatch (seen on the right) is closed on, it would flush with the rest of the deck surface.

The same is done with the rear hatch (not shown here, but you can see it with the image album link on the left). Good thing is that the hatches and their rings fit together really well. Next I would round the internal side edge of the hatches’ ring a bit, cover them with a layer of glass. Completion to the very details in required indeed, in the last trip, I accidentally damaged one of my clothing bag, trying to pull it out of the cramped storage compartment over this sharp, unrounded edge.

serene – 3, part 10

ull and deck parts are basically stitched and glued, those two halves of a peanut shell. But that’s only a basic milestone, lots of jobs required still to make this shell functional. I continue to build the hatches and cockpit coaming, and various other accessories. 3rd image: the cockpit coaming glued in, stained with epoxy filled with black color pigment, later on, some layers of transparent PU paint would make the finish. While the cockpit is easy, it’s a bit more complicated for the hatches.

Both two hatches is of the same shape and size, for the sake of easy constructing (the hatches and their silicone gaskets). The forward hatch is built recessively into the deck, not only to keep a flushed, flat deck, but also simply because the hatch size is a few centimeters larger than the deck’s top, it needs to sink down to fit. It’s a bit tricky to build the recess, so I decide to get along with a rectangular approach (it’s much easier to build, though a circular one would certainly looks much better).

The aft hatch raises about 1 inch from the deck, not too high to interfere with reentry climb – in actions. I would try a new idea for hatch locking, something that’s easy to operate and tight enough (offer some pressure down) to secure the hatches in places and help with waterproofness. Hatches and hatch locks have been causing my headache for long, but it seems, the best solution is indeed simple, I wonder why my common – sense has not come up with it in the first place.

serene – 3, part 9

hat’s the stitch part (of “stitch and glue”), or more precisely, most of it (since there’re still the bow and stern pieces to be put in, but that would be discussed later on), next come the gluing. First the seam lines are “primed” with epoxy (applied with a small brush), then filled with fillet (the tried – and – true 2 – parts epoxy putty 511 that I’ve been using extensively). The “gluing” part is a very time – consuming job, you have to meticulously fill the putty, which slowly flow down under its own weight.

So I have to apply the putty in 2 turns, first fill in just a small bit of them, wait for it to cure, then fill over the first layer another time. This is to ensure that the putty could form curved seam lines that would be easier to glassed later on. You can also mix small batches of putty, wait for about 30 minutes for it to cure partially, then apply it on the seams, the higher viscosity of the slightly – cured putty enables it to better keep its shape. In all, it’s a very time – consuming (and dirty) job!

Next come in the bow and stern pieces. These small triangular plywood pieces need to be bended into curved shapes (see the 4th images below). I simply put them into boiled water for them to soften a bit, then slowly and carefully bend them with a pincer. The bow and stern parts are then temporarily fixed in place with hot glue and duct tape, then permanently glued with epoxy and fillet (putty). Now, the whole hull is rigidly glued in its internal side, similar job is applied to the deck part.

serene – 3, part 8

took great care in aligning a bilge’s parts, to make sure the final piece would come exactly to it designed shape, and to make sure the port and starboard bilges are identical, or else, the boat would have a twisted hull. All joints is slightly sanded, and applied a layer of glass on the internal side. Next come the job of putting everything together using a combination of fastening wires, super glue and duct tape. Having experiences from previous boat, I used very little steel wires this time.

It’s so good to see the bilges fit naturally into their position, with minimum pressing, adjusting efforts. The tendency to take shape easily proves that you’ve all done right in the previous steps: measuring, drawing, cutting and jointing the biges. This is for the first time, you would have an initial impression, of how the boat would finally look like. The computer 3D renderings are too small to have a precise assessment, and of course, it’s always much more lively with a tangible object! 🙂

Looking at these two halves: hull and deck, having a senses of every details, it’s easier to arrange and schedule the next tasks. There’re so many jobs ahead: make and install the (recessed) hatches, hatches’ locks, install the cockpit coaming, rudder pedals and control lines, compass, the bilge pump, etc… and of course the whole complex electric & electronic system. Things should be better done this time, with the lessons learnt (tediously and expensively) from previous boat projects.

serene – 3, part 7

n parallel to cutting, jointing the bilges and forming up the hull and deck parts, I’m also making the cockpit coaming and hatches. They both use the same techniques of bending thin strips of plywood (2 layers of them) around a MDF frame to form the lips’ shape. Now that I have some much better – quality plywood sheets, which is not too easy to crack while bending into extreme curves, this enables me to construct the cockpit coaming and hatches in a much easier and convenient way.

Both 2 hatches would be of the same shape and size, a “rectangular” with 2 circular ends (or could be called: a rounded rectangular). The hatches’ lips and the coaming lips are built up from 2 layers of 4 mm plywood strips, glued together. The flexibility of the ply serves well to the building, the lips take up shape easily, and stay in that shape steadily. In all, they’re all simple really constructions. Special thing about the hatches this time is that they would have elastic silicone gaskets inside.

Recently, I’ve learnt about silicone molding, using 2 – parts silicone mixed together just like epoxy. So I would mold the gaskets specially to accommodate the hatches, and would describe that in another following post. Hatches’ waterproofness has long been a serious issue to me, hopefully, I could resolve it completely this time. An handy (last resort) trick could also be useful: cover a layer of (very thin) PE plastic over before closing the hatch, that would make it absolutely water – tight.

serene – 3, part 6

ext is jointing the plywood pieces: 8 joints for the hull, and just 1 for the deck, to form the bilges that would build up into the boat shape. For the 2 pairs of hull’s bilges, I flip one pair by 180 degree when drawing on the boards, so that to distribute the joints at different places across the boat length, and not to concentrate too much joints into one proximity. That old boatbuilding carpenter’s trick is not completely necessary with modern building techniques, but it’s nice to do so anyway.

The tried – and – true technique of straight finger joint is used as always. The straight joints are easy to cut, and most importantly much easier to be aligned following a straight line for all the jointing parts, so that to make sure all the bilges would be jointed into the correct shapes. All the joints are treated carefully, first is applying a layer of thinned epoxy (using xylene as a solvent, for the substance to penetrate deeply into the plywood), then gluing with epoxy, then a layer of glass on the internal side.

I beveled the edges of the deck parts a bit (at 45 degrees), so that they would fit tightly and nicely together forming straight seam lines. But that’s not applied to the hull, where the cursive seam lines don’t like very thin edges. Experiences from my previous boats showed that, it’s best just to use the squared edges, the thin edges doesn’t stay on each other very well, and would deform, distort the seam lines! You would later just apply thickened epoxy on both sides (in and out) of the seams!