serene – 2, part 8

ad a major setback with making the hatches with wooden strips, the strips didn’t make perfect circles as I’ve expected, although they bend quite well, they’re off by small amount (e.g: 0.5 ~ 1 mm) here and there, and that’s an unacceptable precision for hatches, just a small gap and water could leak in. I had to abandon the method of making hatches using wooden strips, and tried to find some alternative ways instead 😢.

Finally, I resorted to cutting the hatches’ rings (lips) using my routing table. The home – built machine is made quite a long time ago, but this is only the first time making some serious use of it. It’s quick to make a circular cutting jig, as shown in the 1st image: the MDF “disc” would rotate around a pivot point that could be adjusted by sliding the wooden bar. The jig proved to offer good cutting accuracy (sub millimeter).

That’s really good, as I want very tight fits between the hatches’ rings, 3rd image: 2 rings cut, there’re still lots of it to be made. Using solid MDF as hatches’ rings has a serious down side: you would need to fill the MDF with much epoxy for it to be hardened, and waterproof, thus increasing the overall weight. On the other side, MDF is easy to cut into perfect shapes! Decided to go this way anyhow as I have few material choices!

Last image: all the hatches’ rings is cut, 3 hatches, 3 lips per hatch, and 2 rings per lip (since they’re cut in 1.5 cm MDF, it requires 2 rings to form a 3 cm height lip), quite some work to be done, and too much of sawing dust too 😢! And I’ve taken care on “quality assurance” to make sure that each ring is cut at its precise diameter. Though I don’t expect the hatches to be waterproof, it should be watertight as much as possible.

serene – 2, part 7

‘ve been thinking about kayak hatches over and over again. Starting from the very early days with my plywood hatches (in Hello World – 2, 3) which are obviously not watertight, to the Beckson hatches on my Serene – 1 kayak. The Beckson is very good, watertight and even air tight, but sadly that’s only true in ideal conditions. In reality, in multiple days trip, when mud and sand has get into, it would leak by a small amount.

The Beckson is not ideal hatch for kayak in my idea (for other purposes, it may be ok). The reason is that the hatches are built flushed with the mounting surface, and some inner elements are even recessed… When the water washes over (as always happened to the very low freeboard of a sea kayak), and when the O – rings are not properly lubricated, or when there’re some mud, sand inside the joints, water would leak in.

That’s why I decided to build my own hatches for this Serene – 2 new kayak. The idea is really simple: the hatches are raised a few centimeters above the mounting surface, and even when the seals are not too tight, that would suffice to keep most of the water out. Examine many sea kayak hatch designs, I’ve found out that simple thing, that the hatches should be raised (not flushed or recessed) above the deck.

1st image: cutting thin (2.5 mm) wooden strips used to build the hatches. 2nd, 3nd images: the 3 MDF templates for hatch building: the rear, the front and the day hatch, sizes in diameter: 30, 25 and 20 cm respectively. 4th image: building the hatches’ coaming with thin wooden strips around the templates, each coaming consists of 2 layers of strips which bend easily around without cracks and without the need for steaming.

serene – 2, part 6

inished with Serene – 2‘s first paddle, continue to the second one. This would be the pair of paddles, one Greenland style, and one Euro style, that I would use on the new kayak, intended to be slightly smaller in size, and much more lightweight compared to my previous ones. The Greenland paddle is not a typical Greenland one, it’s rather quite short with bigger blades, and the Euro paddle is not of typical Euro style neither 😀.

As it is quite small compared to most Euro style paddles. It’s quite hard to justify my design decisions, but all came from my paddling experiences, that I would need a slightly bigger Greenland paddle for all – round paddling, and a slightly smaller Euro paddle to provide more power in “adversary” conditions. The second one would be lightly & simply built also, with that same kind of rattan shaft, and thin plywood blades.

1st image: the finished Greenland paddle. 2nd image: dry fitting the Euro paddle’s blades and shaft. 3th image: bending the plywood blades, I want them to be just slightly curved around the longitudinal axis, it’s just nearly impossible to bend the plywood around multiple axes, to decided to stay with the simplest blade design. After gluing the blades and shaft together, the paddle would receive a layer of fiberglass all around.

4th image: glassing the second paddle, next to it is the finished Greenland paddle, the pair of paddles near completion, they all need to be “trialled” soon, to evaluate their performances, and to see how they would behave in real world. Final weights, the Greenland paddle: 0.82 kg, the Euro paddle: 0.9 kg, not up to the “standards” yet, but quite near, that’s fine anyhow, as they’re very light (compared to my previous paddles) 😀.

my possession

Kéo cưa, lừa xẻ,
Ông thợ nào khoẻ,
Thì ăn cơm vua.
Ông thợ nào thua,
Thì về bú tí.

leaning and tidying up the workshop in preparation for my next Serene – 2 build. Having a chance to look back at the past few years’ works. Apart from Hello World – 1, my first build, a small canoe which is no longer functional (it was turned into an in – house shelf), the 3 kayaks seen here are built in a 3 – years time span, one in each year. Still feel not having enough of them, still in the quest for my “perfect expeditional kayak”! 😀

Hello World – 1 photo albums: part 1, part 2
Hello World – 2 photo albums: part 1, part 2
Hello World – 3 photo albums: part 1, part 2, part 3
Serene – 1 photo albums: part 1, part 2, part 3, part 4
Serene – 2 photo albums: part 1, part 2, part 3, part 4

serene – 2, part 5

he first image: cutting two hardwood blocks to attach to the paddle’s 2 ends, 2nd image: scraping the paddle blades with a power planer and a spokeshave. 3rd image: the paddle takes its final shape, next it would be sanded, colored (stained with thinned epoxy), glassed then painted. The paddle would receive a layer of fiberglass all over the body, to waterproof the porous balsa wood, and to strengthen the whole structure.

This is only the first of two paddles I’d intended to build. A lightweight Greenland paddle would be my convenient, all – round thing to propel the boat with. But under some particular circumstances, e.g: very strong wind or current, I would need a more powerful tool, that’s why my next one would be a paddle of the usual Euro type, it would be also very lightly built, and has much smaller blades, around 50 x 14 cm in dimensions.

I’ve not yet to really realize which paddle type is better: Greenland or Euro, but thought that they all has their uses in different situations, and decided to build and use… both. Also, my paddles all has become smaller and shorter, their lengths now are around 1.85 ~ 1.9 m. My thought is that sea – kayakers nowadays are using paddles that are longer than needed (around 2.2 m), especially those going for long touring.

I made a terrible mistake, using the wrong duct tape to mask the paddle for coloring. A kind of 3M duct tape is so sticky that it’s extremely hard to be removed after having painted the paddle blades with colored – thinned – epoxy. I seriously scratch the surface while removing the duct tape (with a chisel) resulting in a very poor finish on one blade 😢. The paddle would be perfectly usable, but not as good – looking as I’d expected.

serene – 2, part 4

till don’t have some free times to start my Serene – 2 kayak building yet, and all preparations (mainly materials purchasing) has not been completed. So I start slowly with building some other miscellaneous objects. First are the paddles. A typical WRC (Western Red Cedar) Greenland paddle weights around 0.7 ~ 0.8 kg. My two paddles, built with tropical hardwoods, though durable, weigh too much: 1.3 ~ 1.5 kg.

A lightweight paddle has very obvious advantages on long journeys, and I’ve been thinking about resolving this weighting issue. So I’ve decided to realize an idea which I’ve been having for a long while, in a tropical country like Vietnam, the best material you could use for a paddle is… rattan. Rattan is very lightweight, but it’s also very durable, flexible, and stiff, an ideal material to be used for building the paddle’s shaft.

In order to keep weight to minimum, in combination with the rattan stick, I use balsa wood for the blades. Construction is quite simple indeed, the rattan stick is splitted into two halves at the two ends, and two balsa wood blocks are inserted to form the blades’ shape (see the 3rd image). Balsa wood is quite hard to acquire in Vietnam, I’d made the wood block from 6 small 5 – mm – thick balsa sheets, laminated together.

Next is the job of careful – carving down the blades’ shapes. The 4th image: empty spaces at the two ends of the paddle, that would be the places for two hardwood blocks in order to better resist against cracks upon physical impact. The paddle would receive a layer of glass to further strengthen the structure and to protect it against water. Balsa is too porous and without protection, it would takes on water in the long term.

vong quốc chi ca

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Đạo đức, thịnh, suy, khôn, dại, hay dở đều hiện ra nơi âm nhạc, không giấu được ai. Bởi vậy cứ lấy âm nhạc mà nghiệm được một nước ra thế nào. (Tuân Tử – Nhạc ký)

ề Bolero VN, nói chung âm nhạc là một quá trình giáo dục và cảm nhận, nó gồm nhiều năm trãi nghiệm nên thường ai nghe gì đó là việc của họ, tôi không có ý kiến. Và biết rằng nói ra sẽ mất lòng một số người… Nhưng nhận xét về Bolero Việt Nam nói chung, tôi nghĩ thứ nhạc đó xứng đáng được gọi bằng cái tên: Vong quốc chi ca – 亡國之歌, loại âm nhạc mất nước! Những dân tộc ưa chuộng vận động và tiến bộ phải có thể loại nhạc sáng tạo và sinh động, không phải như Bolero VN ngồi nhai đi nhai lại mãi một mớ nhảm nhí, chẳng đại diện cho ai cả, ngoài cái tâm trạng xấu xí của họ. Chính xác theo cả nghĩa đen lẫn nghĩa bóng, Bolero VN là loại vong quốc chi ca, một loại âm nhạc mất nước!

Vì quyết không sai, đây là âm nhạc của một quốc gia đã mất, và mất vì cứ mãi lải nhải từ năm này sang tháng khác một thứ nhạc kém đến như thế! Kém không phải vì loại nhạc đó sầu não uỷ mị, mà vì nó không có sự sáng tạo, cứ sử dụng mãi những giai điệu na ná từa tựa nhau, nghe 100 bài như 1, đến tác giả còn lười biếng, không chịu tìm tòi cái mới, làm theo kiểu mỳ ăn liền, nghe câu đầu là đã đoán được câu sau, làm gì có tí giá trị âm nhạc mới mẻ nào!? Và những con người cứ mãi lải nhải những loại nhạc ấy cũng không có hy vọng gì có thể mở mang đầu óc mà tiếp thu cái mới! Như Tuân Tử có nói, khi đến một đất nước nào, chỉ cần nghe qua âm nhạc của nước đó cũng sẽ biết ngay là Hưng hay Phế!

Rất nhiều người không phân biệt được đâu là dân ca, và đâu là Bolero. Thực ra, từ ngay cái tên Bolero cũng đã chẳng có nội hàm, ý nghĩa gì, và cũng như cái tên tự nó gọi đó, Bolero chẳng có dính dáng gì đến dân ca cả, mặc dù cũng đã cố gắng vay mượn, đánh tráo khái niệm, đổi trắng thay đen. Đó cũng là tiểu xảo và mục đích của cộng đồng Bolero, đánh đồng tất cả tốt xấu, hay dở, đánh lên một vũng nước đục, gạt bỏ tất cả những thành tựu khác để tự xem mình là một cái gì đó. Bolero VN thực ra chỉ là một quái thai của thời đại nó: âm nhạc thì copy dân ca một cách thô bỉ, ca từ thì chả đâu vào đâu, chủ đề thì nhảm nhí… tất cả nói thẳng ra là một công cụ “phá hôi” để phục vụ cho các mục đích xã hội và chính trị, khởi đầu chẳng có gì rồi kết thúc cũng chẳng có gì!

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text=烟笼寒水月笼沙&font=2&size=18&color=333333
text=夜泊秦淮近酒家&font=2&size=18&color=333333
text=商女不知亡国恨&font=2&size=18&color=333333
text=隔江犹唱后庭花&font=2&size=18&color=333333

serene – 2, part 3

pent a considerable amount of time on optimizing the hull and deck lines. Some little more rocker at the bow, and less (almost square) at the stern. The hull is now a bit finer (less full), hence reducing Cp (prismatic coefficient) further into the [0.48 ~ 0.5] range, quite low indeed. Primary stability is also reduced a bit, with Kmt (transverse metacentric height) at about 21 cm, but the boat is sufficiently stable already.

Cb (block coefficient) is now reduced to 0.33, stepping outside the normal range of [0.35 ~ 0.45]. That is, the boat wouldn’t be very efficient at lighter load, e.g: with the paddler alone. But that would be fine anyhow, since the hull is optimized toward its full displacement, beyond 115 kg. And as confirmed with experiences in my previous kayak Serene – 1, the boat would feel a bit heavier, but more comfortable at full load.

Some other design considerations still need to be done, but they won’t be reflected into the 3D modeling, for the sake of simplicity: the cockpit size and shape, the size and position of the hatches, the rudder and rudder control, etc… Serene – 2 will have a 3rd hatch, or usually called: the day hatch, which locates right behind the cockpit, to store food for lunch and other frequently – accessed things during a paddling day.

2nd image below: the stability curves for various loads: 85, 95, 105, 115 and 125 kg. The curves look exceptionally fine in my eyes, they won’t decrease until 50 degree of heeling angle, and the shapes of the curves closely resemble each other, showing a predictable behavior in hull’s stabilities. Almost done with the designing, I think, next is finding some free times to build the boat in the upcoming months.

serene – 2, part 2

ntil this second sea – kayak, I’ve been able to “read through” the hull designing parameters: Cp, Cb, Cm, Kmt, S, LCB, LCF, etc… interpret them correctly and know quite well what they do mean in real – world boat characteristics and performance. Many days out there paddling in various conditions and many hours spent on the whiteboard (a.k.a the Free!Ship software) make me feel very confident with my designing process.

The hull is shortened to 17 feet, reducing wetted surface area, but with minimum rockers, the waterline length is unchanged, also the designed – displacement is slightly increased to 120 kg, as 110 kg of maximum load is a bit under desire as pointed out in my last 9 days trip. Beam is slightly reduced from 45 cm to 44 cm, but both primary and secondary stabilities is significantly improved. I feel very pleased with this design so far!

Unlike my previous boat, the new one would have a curved deck. It is more difficult to build a round, curved deck, it is also harder to build hatches, compass cup, bungee cord anchor points and other parts… onto it. But with a curved deck, the boat will look nicer, less windage, and weigh less overall. Looking from above, it shapes exactly like a bullet, should I engrave a motto onto it: built like a gun, runs like a bullet !? 😀

The most important design decision is to increase the amount of deadrise. In my experiences with Serene – 1, the kayak has excellent sea – keeping abilities in rough conditions, something I didn’t feel with all my previous boats (e.g: the Hello World -3, which has a much flatter bottom). I would attribute that ability to the deeper V – hull, which offers quite a low primary stability, but should let you at ease in waves & turbulences.

serene – 2, part 1

‘ve been thinking a lot about the design of my next build. Serene – 1 is a good kayak, she has proved that during my last 9 days trip crossing all mouths of the Mekong river. The boat shows her excellent abilities in various conditions, big waves, strong winds and turbulences, even when overloaded a bit above her designed displacement, she gave me a kind of confidence that I’ve never felt with any of my previously – built boats.

In the quest for an ideal kayak that perfectly fits me, I proceed to designing my next boat, Serene – 2. Some lessons learnt from my last trip are immediately applied: first is a transom – mount rudder. I’ve been into conditions of strong wind blowing whole day, and without a rudder to help adjusting the bearing, corrective paddling would be extremely fatigue. This will have an influential effect to all other designing considerations.

LOA is reduced to 17 feet, approximately 3 times the height of my body. Since maneuverability is entrusted all to the rudder, the boat would have a very full waterline length, very little rockers at two ends. I decide to reduce prismatic coefficient – Cp further to around 0.5; my sustainable speed in reality (paddling at sea with full load) is only around [3 ~ 3.5] knot. There is no reason to waste energy for a higher speed that I can not sustain.

Block coefficient – Cb is reduced to 0.35, this would improve directional stability a lot. In Serene – 1, this value is 0.45, which explains the boat directional un – stability on long distance. Transverse metacentric height – Kmt increased to 21 ~ 22 cm, roughly equal to most popular Greenland sea kayaks, and hence greatly improve primary stability. With Serene – 1, this value is 17 cm, enough to frighten any novice paddlers.