Anh mãi mê về một mầu mây xa,
Cánh buồm bay về một thời đã qua…
t tooks just a few hours to learn the new software and construct the basic 3D objects: hull & deck. The time – consuming tasks are adjusting the shapes and playing around with hydrostatics. Some basic measures: LOA / LWL (length overall / waterline): 5.50 / 4.44 m, BOA / BWL (beam overall / waterline): 0.483 / 0.451 m, Draft: 0.1 m, S (wetted surface area): 1.66 m2, Cp (prismatic coefficient): 0.5619, LCB (longitudinal center of buoyancy): 0.5150, LCF (longitudinal center of floatation): 0.5192.
Additional hydrostatics parameters, VCB (vertical center of buoyancy): 0.0590 m, Cb (block coefficient): 0.4684, Cm (midship coefficient): 0.8336, Cw (water plane coefficient): 0.6385, Displacement: 0.096 tonne… Well, I wouldn’t pretend that I fully understand those parameters above, cause they contain insights into a boat that can only be correctly interpreted by an experienced designer. However, I’m tweaking around to optimize the parameters toward a higher Cp, higher LWL, and lower S.
Drag (resistance) predicted by the KAPER algorithm looks fine till now, however, the displacement is sacrificed already, 96 kg, barely enough for me (65 kg) plus 30 kg of gears. This gonna be a demanding boat with low primary stability, not recommended for beginner. It takes some real world experiences to understand why low initial stability is indeed a good thing, and why a kayak which appears to be very stable on flat water could probably throw you up side down in bumpy conditions.
Some rough calculations on the energy required to propel a kayak. My target speed is 7 kmph, or 3.8 knots. From the numbers recorded by my Garmin over the years, in normal big rivers and sea conditions, speed is reduced by 1/3 compared to the ideal condition of flat water.
That is you have to struggle at 5 knots to assure that 3.8 knots. The Kaper algorithm tells you that, this Serene – 1 hull produces a resistance force of 27.35 Newton at 5 knots (or 2.57 meters per second). Making the multiply: 2.57 x 27.35, that’s the output required: 70.39 Watt!
n the progress of learning to design my new kayak… you know its name already. I’m using Free!Ship, a CAD software running on Win XP virtual machine (with VirtualBox) on my Macbook. I haven’t used any CAD software before, haven’t designed anything 3D, not to say about a watercraft. So why designing a kayak!? Well, first, just for the fun of doing something yourself from A to Z. Second, though I’m no naval designer in any sense, I believe I have some guts on how a good kayak should be!
Many kayaks are designed for 70 ~ 90 kg paddlers on average, I’m not that bold, and I need something slimmer, lighter, with the drawback of sacrificing some load capacity of course. I’m re – modeling my kayak after Björn Thomasson’s Black Pearl, using just some publicly – available pictures of the boat. And it’s not a copy, there’re some modifications: slightly narrower beam, slightly less rocker, and slightly deeper V – bottom. And I would stick still to my familiar stitch & glue construction method.
Why stitch & glue!? Strip build generally offers best boat shapes, but look at the Inuit people’s SOF (skin on frame) kayaks, those “hard chines” suit naturally to S&G, the method is simpler and takes less time (which I don’t really have much for now). It gonna be not an easy process: just for the hull, adjust the 60 control points back and forth, recalculate the stability and performance parameters, repeat again and again until you’re satisfied with the results. I hope I can finish the design in about a month or so.
Recently, I’d noticed that Japanese kayakers usually use kinds of slim, long kayak similar to the Black Pearl, that’s quite understandable cause the body – building of Japanese is Vietnamese alike, we’re not too bold. Use a slimmer, lighter boat, and pack your gears cleverly for longer trip!
It’s interesting to know that, in the old day, in building kayaks, the Inuit people has “recipes” to measure the size of the boat: length should be 3 times the height of the paddler, width should be the hip plus somewhere from 4 to 8 “finger”. Well, like shoes, boat is tailored to match the user.
Giọt mưa trên lá, tiếng khóc chơi vơi,
Thế giới lạc loài, chưa thoát ra phận người…
hừng này tạm đủ như một lời giới thiệu ngắn gọn về giọng ca Thái Thanh, hơn 300 ca khúc của nhiều nhạc sĩ khác nhau: Phạm Duy, Phạm Đình Chương, Dương Thiệu Tước, Hoàng Trọng, Văn Phụng, Văn Cao, Lê Thương, Trịnh Công Sơn… Các ca khúc được xếp theo thứ tự ABC để tiện tìm kiếm. Những tựa in đậm là những ca khúc tôi thích và thường nghe. Chất lượng âm thanh không đồng nhất, tốt có, kém có, nguyên bản nhiều, remixed cũng lắm. Chất lượng âm nhạc… cũng thế!
Nhưng có hề gì, miễn là cảm được giọng ca Thái Thanh, hay nói như NS Phạm Duy:
Thái Thanh chỉ cần cất giọng là người ta đã mê, bất kể bài nào. Đến giờ, không còn mấy ai cảm được cái kiểu luyến láy nhấn nhá như trước nữa… Một số người vẫn cất công kể lể nhạc xưa thế này, Thái Thanh thế kia, blablabla… Nhưng tôi không nghĩ là họ đã nghe đủ, và càng không tin là họ có hiểu một tí gì, vì dù có nghe cũng chắc gì đã hiểu!? Thực ra tôi không cần đến 3 giây để nhìn ra những điều như vậy!
Dù đó là những đĩa than đã mòn nhẵn với thời gian, hay những thước băng cối đã nhão đến mức khó nhận ra âm điệu gốc, từ những bản thu mộc âm thanh mono cách đây hơn nửa thế kỷ, hay những thu âm CD số hiện đại sau này, thì giọng hát Thái Thanh vẫn không thể lẫn vào đâu được. Nhiều chất giọng cũng cao như thậm chí là hơn Thái Thanh, nhưng những bội âm trong chất giọng của bà là điều mà không một ai bắt chước được, không một kỹ thuật hiện đại nào có thể tái tạo được!
Như dòng sông ra đại dương, qua bao ghềnh và đá cheo leo.
Đấu tranh này bền lòng em ơi, mới tới ngày nắng ấm…
ake my little free time to do some updates for the workshop, it’s covered with layers of dust after months without any woodworking projects 😢. First is the wall – mounted kayak rack, a simple structure to stack – up my boats to better utilize the room’s space. Seen mounted on the rack are my HW – 2 & HW – 3 kayaks. The HW – 1 canoe has been in dis – use for a very long time already, so I decided to turn it into… a shelf!
Cut out the aft part, attach a MDF sheet to make a standing base, erect it upright et voilà, you have a shelf to store various miscellaneous things! 😀 I was a bit hesitating in “scarifying” a canoe in such a way, but I would stick with sea kayaks for some years to come, would be back to canoes at an uncertain time. Also, I’m in the initial stage of planning for my next build, something I would start by designing it, or at least learn to design it!
n update to a previous post on Vietnam Navy training sailboat, construction and fitting are by now almost completed, delivery is estimated sometime next month in Cam Ranh port. The boat is named “Lê Quý Đôn”, after Vietnam 18th – century prolific scholar and polymath, can see it clearly at the boat’s bow, still not sure which number (HQ – xx) would be assigned to this Naval training vessel. To be honest, I’m feeling envy with those 30 Vietnamese sailors being trained onboard that watercraft!
hông tin thêm, tiếp theo 1 bài trước về con tàu buồm huấn luyện của Hải quân Việt Nam. Quá trình đóng và trang bị tàu đã gần như hoàn tất, sẽ chuyển giao cho phía Việt Nam vào khoảng tháng sau ở cảng Cam Ranh. Con tàu sẽ mang tên “Lê Quý Đôn”, đặt theo tên học giả uyên bác người Việt sống vào thế kỷ thứ 18th, tên đó đã được sơn rõ ràng ở mũi tàu, nhưng hiện chưa rõ là con tàu sẽ mang số hiệu (HQ – xx) nào. Thực lòng mà nói, tôi đang cảm thấy ghen tị với 30 thuỷ thủ người Việt đang được huấn luyện trên tàu!
One may wonder what’s the role of sailboat training in modern naval warfare, where ones sit in air – conditioned rooms, in front of LCD displays, with high – tech missiles at their fingers’ control? First, sailboat training help forging a sailor’s strength, moral and will, second, it equips the soldiers with skills: rowing, swimming, other survival skills… so that in the worst case that could happen to their ship, they know that they could still survive. That would bring more confidence for them to do the utmost into a naval battle.
Sẽ có người hỏi tại sao lại dùng tàu buồm, trong chiến tranh hiện đại, mọi người ngồi trong phòng máy lạnh, trước màn hình LCD, chỉ nhấn nút một cái là các tên lửa công nghệ cao được phóng đi. Để trả lời, đầu tiên huấn luyện thuyền buồm sẽ giúp rèn luyện thể lực, tinh thần, ý chí cho học viên. Thứ hai là trang bị cho họ các kỹ năng: bơi lội, chèo thuyền, và các kỹ năng sinh tồn khác… để nhỡ khi tình huống xấu nhất xảy ra với con tàu, thì các thuỷ thủ vẫn còn cơ hội sống sót. Chính những kỹ năng đó mang lại sự tự tin, giúp họ dám liều mình trong chiến trận.
he 80s again, another film that I’d seen when I was a young boy, and liked it very much: The Blue Lagoon. Broadcasted on Vietnamese (analog) TV under the title: Eo biển xanh, the film was a strange phenomena, in an extremely closed and strictly censored environment as Vietnam as of the 80s. It’s the 1980 adaptation from the book of the same name, there’re many other adaptations as well: 1923, 1949, 1991, 2012…
The Victorian era,
two children shipwrecked alone on a tropical island. They thrive on the bounty of jungle and lagoon, the boy grows tall, the girl beautiful. When their love happens, it is as natural as the sea, and as powerful. Despite its extreme nudity, negative reviews, quite low rating etc… (which I only know by now), back then, I simply did (and still do) just love it! 😀 To know why, see the movie screenshots below!
l ya toujours un sourire de plaisance sur mon visage en écoutant cette vieille (1956) chanson de Dalida. Et c’est deja très longtemps que nous étions comme ça, un(e) petit(e) Bambino / Bambina, naïvement (et profondément) tombé amoureuse… Regardez la vidéo pour voir la vraiment vivante, aimable Dalida… Je peux seulement dire:
Ta musique est plus jolie que tout le ciel de l’Italie…
Mắt được thấy dòng sông ra gặp bể,⓵
Ta, với mẻ thép gang đầu, là lứa trẻ sinh đôi!
omeone eventually turns on the tap, and the rainy season is officially here, it comes so late this year. I haven’t had the best physical preparation, been quite busy for the last couple of weeks, but can’t wait anymore to start the long – planned trip. Saying to myself: just do it, go out there, play it “safe and sane”, and for fun, for whatever the nature might throw at you. I started my trip to Đồng Hoà, the small town – let opposite of Vũng Tàu on the other side of Gành Rái bay, 4:30 AM, June 16th.
The lunar phase is Waxing Crescent (unlike last year, it was Full Moon), tidal coefficient is in [80 ~ 90] range, a high value (not extremely high), but I don’t really care about them anymore. The general plan is going through Lòng Tàu river to Gành Rái bay (40 km) then 20 km on sea to reach Đồng Hoà. The next day would cross Đồng Tranh bay, then make it through Soài Rạp river back to Sài Gòn (55 km). The area is a complex joinery of many rivers, in essence, going around the Cần Giờ mangrove biosphere reserve.
The trip starts smoothly as I expected, speed increases gradually as the tide was coming to help: 6.5, 7.0… 9, 9.5… 11, 11.5, 12… top at 13 kmph, that’s really good. The tide is not as strong as last year, but my HW – 3 kayak goes faster. The Lòng Tàu river is narrow and deep, fast running water with some large, dangerous – looking whirlpools, but that’s all. I finish the first 20 km one hour sooner compared to last trip, which is quite obvious since I paddle now a better kayak, not a 14 footer anymore.
The next leg completed at 9:30 AM, that’s superb! I stop at the river mouth, having a break and lunch for 1 hour, before continue on. The hydrofoils run this route every 45 minutes or so. It’s so fun (and thrilling) to watch it coming straight on you, looking from the head, with those “legs” lifting the whole body above the water, exactly like a giant spider. Dangerous spiders indeed, have been causing numerous accidents, fortunately, those Soviet – made machines can be heard many kilometers away.
The next 10 kilometers goes on as smooth, it’s very pleasing to roam the immense, peaceful water space of the estuary. I was thinking I could finish the day within 10 hours of paddling, but life turned out to be not that easy. As soon as I round the Cần Thạnh horn, wind and wave gradually pick up, they get stronger and stronger, and they came straight from where I was going to. I knew that the weather wouldn’t be good these days, but I just didn’t think my next couple of hours to be that hard.
Waves soon reach 4 feet high, and even more, luckily, the wave lengths are still a bit long, they are not too steep. A perfectly – fun environment to play against the waves and winds, as I could rarely be in the same situation again, to horn my “acrobatic skills” with a kayak. I was quite tired already, but still eager to take the chance to enroll in that “advanced kayaking course” 😀. The sky was divided into two halves, one white and and black, from Đồng Hoà direction, a tropical gale was coming.
The last 3 kilometers, I was in the gale, the wind gusts were so terrible that I couldn’t even hold the paddle upright, making advance was really really hard. But I had nothing to fear: I’m quite closed to my target already, the lowering tide seems to make the distance looks further, but actually the water is shallow, less than 2 meters, I could easily beach the kayak at any moment if something goes wrong. I reached Phương Nam Pearl resort at 4:30 PM after 12 hours of paddling, exhausted!
It took 7 hours to complete the first 50, and it took 5 hours to complete the last 10 kilometers! I spent some last daylight hours to wander the beach, the lowered tide left millions of small fishes imprisoned in those water ponds, jumping and sparkling like silver. And the sea birds were gathering for their ‘clamorous’ party, in the mist of heavy rain and strong wind. The resort offered me a 70% discount since it was not weekend, and I need some comforts to recover in preparation for my next day!
I begin the next morning slowly with breakfast and coffee, thinking that I could finish the 55km return trip in about 12 hours. It turned out that I’m completely and severely wrong. Departed at 8:30 AM, 10 km across Đồng Tranh bay into the Soài Rạp river mouth, there were some waves, but nothing particularly difficult. I’d thought that it should be calmer on the river, but Soài Rạp is completely different (compared to Lòng Tàu river), it’s just so wide, and the weather deteriorates toward the afternoon.
The next 20 km up the river, I found myself playing the “acrobatic game” again! Waves were large, even larger than yesterday, surely wouldn’t give you a safe feeling at all. And the winds signal that another gale could come at any moment. When it did come at 1 PM, I made a quick decision to immediately take shelter in the mangrove forest, white breaking – waves were all across the river, and I can’t risk wasting my strength since I still have 30 kilometers ahead of me to complete.
It was where the Vàm Cỏ branch joining the Soài Rạp river, turbulences, and the gale was so brutal, I had to wait 1.5 hours before being able to go on. 6 PM, passed Vàm Sát branch, paused for dinner (sliced bread with canned tuna, some bananas). 7 PM, passed Hiệp Phước ferry, it was dark already, and it’s not immediately obvious for me to recognize that my speed stalled significantly. A quick check on the Garmin shows that, even though I was paddling hard, my real speed was under 1.5 kmph.
That means there’s a 5.5+ current here! I’ve never seen such a powerful opposite current! The Garmin map shows a very sharp S – shape river turning, which explains the strong current, and the tide was at its extreme too! I felt very… despondent, only 15 kilometers from my destination, but that would mean many more hours of paddling. I had to continue on anyhow, some desperate paddling struggles, my shoulder was in great pain, and my arms swell up like two bunches of bananas.
The last several kilometers were very painful, I have to stop for a break often, very inconvenient to navigate in the dark along the Hiệp Phước port area, where there’re many freighters traffic. I reached home haft past midnight, after 16 hours of paddling, not exhaustion, but a ‘worn – out’ condition to be correct. But never have I had the idea of giving up, on the other hand, I was feeling very very pleased as I’d completed what’s settled to be done at the beginning of the journey.
The Garmin – recorded route viewed on Google Earth, first 6 images: the 6 legs of the trip, last 2 images: day 1 & 2 of the trip, the 6th image: the route terminated some kms from my home cause the Garmin battery ran out, I had a pair of backup, but too tired to replace then. Thanks to the Garmin, navigating is easy and convenient. But don’t forget the paper maps, I always check the routes on papers, note down the distances, headings, tide table etc… learn them by heart before any trip.
The rainy season has just come back, at its full throttle these days. It rains cat and dog every afternoon, and there’re gales a few times in a day. Those gales usually won’t last very long, but could be very dangerous since the wind gusts could momentarily reach 7, 8 or more on the Beaufort scale. Just three days ago, a large fishing boat capsized with 37 people on board, right on this Soài Rạp river during a gale, resulting in 2 deaths. So, I proceed my trip with lots of cautiousness.
But after a gale, it’s always very calm, the water looks tranquil as if nothing has happened. And so is my mood, a kind of internal serenity for my mind that I surely wouldn’t trade anything for it. Now sitting here writing these lines, but all I would like to say is that:
there’s no wifi on water whatsoever, but I’m sure you would find a better connection there!, not just a disconnection to the madnesses of modern society, but a true connection to the nature, to your inner self…
You may have noticed from the pictures that I had a life vest on the back of my kayak, but in the gale at the end of the first day, it was blown away, and I continue the rest of the trip without a PFD (Personal Floating Device). During the gale, it is very hard to make a steady picture shot, and something went wrong with my GoPro (it shoots still images instead of videos), and I couldn’t have just a second to fix it, was worrying about a potential capsize, so I missed many of the interesting moments.
The GoPro 3 has some drawbacks, it couldn’t produce fine image quality in lower – lighting conditions, such in a gale, and when water dust has covered all over its glass box, the resulted video is very blurry and obscured. But I don’t really mind, those fascinating moments were in my memory already, like having a higher adrenaline level in your blood, those playful hours facing the big waves, trying to keep your boat balanced, and make advances, meter after meter, to your destination.
This is only my first longer trip, 2 days of hard paddling, 12 hours for the first day, and 16 hours for the second, 115 kilometers in total. Nothing comparable to the feeling, you and yourself, the long road ahead, and a commitement to complete it no matter what. This is the first time I tasted the real hardship that nature could throw at me, gales and waves, strong current… unlike my last year’s trip to Vũng Tàu, in which I was just lucky to have it done smoothly within 12 hours with good weather.
There’re lots of things learned from this trip: some improvements to be made in kayak building, some more adjustments for equipments, gears, preparation for food and drink… the experiences and skills to handle rough conditions… and above all, the understanding you achieve, not only on wind, wave, current, navigation… but on yourself. That’s all about the purposes of longer journeys, you don’t win the mileage, you don’t win the nature (gales or current), you just try to… win yourself!
Đồng Hoà and its nearby sister town Cần Thạnh are both very small but peaceful towns, unlike the much bigger Vũng Tàu city on the other side of they bay. Small communities living on fishing and planting (mango), and tourism. I usually go there on motorbike, for one single day, every few months or so, just to stand by the shores and watching, listening to the sea. Out there, the great blue sphere of ocean, white breaking waves, my “playground” for many years to come!
It’s simply just pleasing to wander the shores when the tide was lowering, or to watch the sun rising with a cup of coffee. You could also go to its fishing harbour to buy some sea foods, or visit the “commune house”, a small local “museum”, which preserves a large whale’s skeleton, and exhibits some models of fishing sail boats that were used by the local inhabitants (images below). Pieces of tradition and history could still be found here and there along this narrow but lovely strip of land.
⓵⏎ Một câu thơ cũ (Chế Lan Viên) với phép ẩn dụ có phần lạc hậu.
Mắt được thấy dòng sông ra gặp bể: ý nói mở rộng tầm mắt và tâm hồn để thấy những điều rộng lớn, thực ra có nhiều thứ còn rộng lớn hơn nơi dòng sông gặp bể, tuy nhiên cũng đã là một trời khác biệt so với những kiểu “lòng người như cống rãnh” của thời bây giờ.
Ta với mẻ thép gang đầu là đứa trẻ sinh đôi: ý nói sự cứng rắn, mạnh mẽ của con người cũng như gang thép, thật ra như tôi thấy, ý chí con người còn ngàn lần cứng hơn.