It was getting close to 5pm as two small sailing boats luffed up into the easterly breeze which although moderating a bit, was still fresh and blustery. As the sails snapped and flogged, one person from each boat dropped over the side into knee-deep water and each grabbed hold of a boat by the bow.
In the bigger of the two vessels, Mike Rowe quickly released the main throat and peak halyards and the mainsail dropped neatly into its lazyjacks. Already the small jib was rolled up around the wire-reinforced luff which also served as the forestay, leaving the boat with a single sail standing on the mizzen mast which pierced the aft deck adjacent to the stern transom. This mizzen sail was undoubtedly a complication to the rig, but Mike knew it was superbly practical, and paid its way handsomely. Right now, the mizzen sail was sheeted in tightly, and was holding the little yawl securely head-to-wind.
Having come to a halt a short distance away, the 15-foot sailing dinghy which formed the second boat in the fleet, was also being stripped of sail by her young skipper, although he did not have to trouble with a mizzen. He conducted his sail lowering operation one-handed by leaning over the deck of the boat while keeping hold of her bow with his remaining hand.
Mike and his two sons were feeling the effects of a long day exposed to the elements. They had started early from a roadside camping area, arriving at the launching ramp mid-morning. As usual for people with busy lives, it had taken some time for them to sort their belongings and the ships stores, so that by the time both boats were afloat, loaded, and tow vehicles safely parked, the sun had passed its zenith. However, although the travelling and loading arrangements took a while, the operation of the two boats was efficient and neat. This was due to a combination of design, development, and experience. Not one of the three was a slave to fashion.
So, at the risk of boring some readers, but hopefully passing on some useful information to others, here are some details.
The larger of the two boats was a V-bottomed plywood yawl of 17-1/2ft length-on-deck, sporting a transom bow (i.e. a praam or scow hull - blunt at both ends), and a small cabin whose sides extended to the gunwales. She had a large cockpit with wide side seats and a small, watertight and self-draining foot-well. Down below the cuddy-cabin was unusually voluminous and airy for a boat of such modest overall dimensions (17ft 6ins by 6ft 10ins), due to the cabin sides extending to the gunwale, and most importantly, because of the transom bow. This made her usable space comparable with that of a conventional boat four or five feet longer.
In terms of volume, the shape of the boat was a really important factor, but what made her interior particularly open and uncluttered was the total absence of a centreboard and centreboard-case. Instead of a centreboard the small yawl carried a pair of leeboards slung externally on each side. Many people understand that leeboards are very effective and efficient as a means of providing lateral plane for getting to windward and for reaching, but it is less well understood that certain hull shapes are better suited to leeboards than others. This little cruisers hull was close to ideal for leeboard use, and in many ways was similar to that of the wide, shallow craft of the Netherlands and Germany where leeboards are so common.
The other boat was a light sailing dinghy of 15ft by 5ft, sporting a short, free-standing mast which supported a sprit rig of generous proportions and a smaller flying jib. The boat was set up specifically for cruising, with a useful galley box wedged under the main thwart, and substantial ground tackle (i.e. anchor, chain and rode) well located between the forward bulkhead and a purpose-built semi-bulkhead.
Large emergency buoyancy tanks were built-in under the fore and aft decks and also under the large stern sheets (rear seat). The emergency buoyancy, combined with the light-weight hollow wooden mast, meant that this boat was fully capable of self-rescue. So far on this boisterous trip, the young skipper had kept the jib stowed, and had a reef tied in the mainsail.
Having done a temporary stow of the sails and setting light anchors in the shallows, the three headed up the beach to stretch their legs and to have a snack at the tree line. That idea lasted about two minutes before the cloud of mosquitoes and midges sent then on a hasty retreat to the relative safety of the water. Piling into the larger boat, Mike and Geoff upped anchor and allowed the breeze to blow them back into deeper water. Mike then lowered the small outboard (a two horsepower air-cooled Honda four-stroke which weighed only 12.5kg) and motored to a spot where they could ride out the night regardless of the state of the tide, and the strength of the wind, as long as it stayed anywhere from a north-westerly around to a southerly. Mike felt confident they would have a safe night.
With the anchor set and the anchor rode safely wrapped with padding where it ran through the bow chocks, Mike and Geoff looked up to see Dave rowing towards them in the sailing dinghy. Knowing just how important it is to reduce windage when rowing, he had lowered the mast, which lay to one side in a bundle with the sail and sprit. Because the mast was free-standing, lowering had taken him no more than thirty seconds, and he was enjoying the sensation of rowing a boat which had been designed with the rowing thwart in the correct place and height. Dave had made the oars with his own hands, just as he had the boat and spars, so the whole operation was filled with pleasure and satisfaction.
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| Mike and Dave leathering home-made oars |
Leaning over the stern transom of the yawl, Geoff made the sailing dinghys painter fast to a cleat on one side of the aft deck, while Dave grabbed the gear required for a night aboard the mother ship. The two boys worked together to set a boom-tent under the bundle of sail and spars, all well supported by a topping lift and lazy-jacks. The boom tent was a very simple affair, being a four-sided piece of fabric with a series of ties sewn along the centreline. These were passed over the sail and spar bundle and tied off with reef knots. Once the outer edges had been laced onto the line of hooks under the gunwale moulding, there was a large tent over the cockpit seats, allowing all three to sit protected, and giving Dave his own bedroom as he slept on the cockpit seat for the night.
A key to the success of the boom tent was the fact that the forward end extended well past the aft end of the cabin. This meant that even during periods of rain, the cockpit remained fairly dry, while lots of air was able to come in to ventilate the living space. Mike really enjoyed the sensation of being under the boom tent, or inside the cabin, while rain drummed down at the end of a hot summer.
All three were ready for sleep, even though it was still only evening. An early start, salt-air, exercise, and sun had all combined to produce a feeling of healthy exhaustion. Mike was aware that food was important in this circumstance, and he also encouraged everybody to use fresh water and towelling to wipe encrusted salt from their faces. It is amazing what a morale-booster it is to get the salt off, even if it is just the face.
Food was simple to prepare. Mike sat on the end of one of the bunks in the cabin, and passed out some large cans of beef and vegetables. He was very careful to select high-quality canned food for these trips, and had discovered that many of the better companies were offering the option of low-fat and low-salt menus. Normally, he removed the paper labels and wrote the name of the contents directly on the can using a felt-tip pen. They all drank a good amount of water, and Mike also downed a couple of glasses of red wine in a contented fashion.
The plan was to meet up with a friend and Mikes third son prior to lunch the following day. They were following in a long, slim powerboat that Mike had designed for his friend, but they had been delayed by transportation issues. However, the speed of the powerboat meant that their trip from the boat ramp would only take an hour-and-a-half, so all would be well.
Meanwhile, our three adventurers were settling down for the night - Mike and Geoff comfortably arranged on their individual bunks below, and Dave, already asleep, on a sleeping mat on the port cockpit seat.
The occupants of the boat slept soundly, and elements of the design of the boat aided in the sleeping process. Firstly, the bunks in the cabin were a full 24 inches or 610mm wide for their entire length of 6ft 6ins or 1981mm. It is usually said that a bunk should be at least 22 inches wide, so for such a small boat, the bunks were exceptionally well proportioned. This was made possible because of the transom-bowed shape of the boat. Secondly, the boat design incorporated a large vent in the forward cabin bulkhead, and this vent was baffled so as to allow a full flow of air, but keeping rain and spray out. Mike was astonished at the large number of boats which had stuffy cabins because of poor ventilation.
Lastly, although the boat had a very shallow vee-shape amidships, the bottom panels twisted significantly to produce a vee of 32 degrees deadrise in the forward sections. This meant that the drumming of wavelets under the hull was reduced to a pleasant lapping sound, which seemed to help true sailors descend into a deep and healthy sleep.
Next day promised to be exciting, with a convoy of three boats and the likelihood of some serious exploration.
Morning sunlight was flickering and reflecting off the paint inside the cabin as Geoff woke the next day. He could see his father quietly reading as he lay on the bunk opposite, and it was only then that Geoff started to take notice of the stowage arrangements in the boat. The previous day had been too busy for him to be aware of such details.
Behind Mikes head as he lay on the bunk (i.e. forward in the boat) was a low bin formed by a semi-bulkhead at the head of the bunks, and the main cabin bulkhead 11ins (278mm) further forward. This bin was 7ins (176mm) deep and 4ft 10ins (1474mm) wide. The bottom was formed by the vee-shaped bottom of the boat. Geoff noted that it currently held things such as a hand-held GPS, a couple of rolled up charts, two PFDs and a dry-bag which he assumed contained things like his fathers car keys, wallet, and camera.
Moving his glance further forward, Geoff noted two cut-out openings in the lower part of the cabin bulkhead which lead into more stowage spaces. It turned out that big storage bin behind the openings was 9-1/2ins (246mm) high by 4ft 10ins (1474mm) wide, and 11ins (278mm) deep. Plenty of handy space for loose items that would be needed in the cabin.
Just then his old mans smiling turned towards him, and he knew it was time to start having some fun on the water!
Geoff clambered out of the cabin of the small boat and sat under the boom-tent in the roomy cockpit. On the cockpit seat opposite, his brother lay asleep in his bedding, squinting each time a small patch of sun passed across is closed eyes. Looking aft from under the boom-tent, Geoff could see that low tide was once again approaching, and a fringe of mud lay between the blue water and the green of the hillside. Being an impulsive sort of a person, Geoff was tempted to dive over the side for a morning swim, but the combination of an unknown water depth and the possibility of lurking crocodiles made him think better of it. Reaching over the transom, he swept a handful of salt water over his face and flicked the remainder at his sleeping brother.
Down below in the cabin, Mike Rowe was attending to far more important matters. His home-made galley box was open and a dual fuel stove was already beginning to boil water for his morning coffee. While the water was heating, Mike had been perusing the chart covering the days proposed trip. The idea was that Mikes third son, Steven, would join them that morning along with their family friend, Ian, both of whom should already be on their way to the anchorage aboard Ians powerboat. The convoy of boats would then head north-east and east for about 35 km (19 nautical miles) to their final camping destination. Because Ians boat would be so much faster than the two sailing vessels, Ian, with Steven and Geoff aboard, intended to detour about 10 km offshore to investigate a rocky island which he hoped to climb in the coming days.
For the next hour and a half, Mike attended to housekeeping jobs aboard the boat while Geoff and Dave explored the nearby coastline, having rowed ashore in Daves boat after a hasty breakfast. He left the boom tent erected so as to protect himself from the tropical sun which was already making itself felt despite the early hour. Just as the others returned to the boat and Mike placed himself against the main bulkhead to drink his second cup of coffee of the day, they all heard the sound of a distant outboard motor. It appeared that for one of the few times in his entire life, Ian was on time.
Mike dived below and quickly returned with a set of binoculars and rapidly trained them on the approaching boat. Although he had been out on the boat himself several times, this was the first opportunity he had had to observe her action in open waters. There was a moderate sea running in from the north-east and he was interested to see how the boat would handle a quartering wave pattern. Although she was fully 26 feet long, her 66" beam made her a much smaller boat than most people would have imagined. Mike had designed her at Ians request, and both men were very keen to gather information about her performance. The pair shared the opinion that the majority of planing powerboats are overpowered, overweight, and designed to operate at speeds which are rarely practical on open water. The boat which Mike had designed for Ian represented a strenuous attempt to produce a boat which was both economical to operate, and economical to build.
Three Brothers as the boat was known, had been proportioned to operate most effectively at a speed length ratio of 2.2, which in this case is a speed of 10.5 knots or 19.5 km/h. As part of the design process, Mike had produced the following performance estimates for Ian to think about: -
· Displacement 0.82 tonne including 288kg of passenger weight
· LWL 22.6 ft
· Power to achieve 10kts - 13.9hp
· Power to achieve optimum SL ratio 2.2 - 15.6hp
· Speed with 30hp (Crouch’s Planing Speed Formula) - 19.3kts
· Speed with 40hp (Crouch’s Planing Speed Formula) - 22.3kts
· Speed with 50hp (Crouch’s Planing Speed Formula) - 25kts
Ians boat was being powered by a 30 hp two-stroke Yamaha outboard with three cylinders in-line, for the simple reason that this was the engine he already had. It had originally been his plan to purchase a four-stroke motor of about the same power, but the current one was performing so well that he no longer saw the need to change. Although the boat could achieve the 19 knots predicted, Ian normally throttled back to cruise at about 12 knots, a speed at which both the engine and boat felt comfortable, with the lean and sharp hull cutting through waves without pounding.
After meeting up and swapping gear, crew members, and stories, the flotilla set off for their destination. The skippers of the two sailing craft were both avid sailors who enjoyed the technical side of the sailing and never became bored along the way. The remaining three in the powerboat were made of different stuff, and relished the thought of a run out to the off-shore island prior to heading into the camping spot for the night.
Now, there will be some among you who say that ten or twelve knots is not very fast, but let me tell you it is a lot faster than any sailing most of us will ever experience. Yes, I know that weve all had rides on catamarans or skiffs which have travelled fast on a particular point of sail, but taken over over a number of trips, not many people can truthfully claim an average of more than four knots. This takes into account calms, tacking, adverse tides and other things. There is no doubt that if you are on a schedule, a powerboat is what you need, and twelve knots (22km/hr) will get you over a lot of water in a day. The high-speed planing boats with huge, fuel-guzzling motors might get you there faster if the weather is kind, but will you be able to enjoy the scenery and ride? Not in my experience.
The path our powerboat crew took ended up being about 42km, so excluding exploration their journey time was 115minutes. On the other hand, Mike and Dave, would probably have averaged 3 knots given tacking and an adverse current, so their 35km would have taken 380 minutes or nearly six and a half hours! In fact, for about half of the distance they both ran their outboards and then sailed when the wind increased and the point-of-sail improved to give them an average speed of 5.5 knots - so 3.4 hours for the entire trip.
Both crews claimed to have enjoyed the day - the powerboat people having explored the island for a few hours and done some fishing, while the two sailors relaxed at their sport, enjoyed the challenges, and ended up getting to the destination first. Had the sailing boats not had auxiliary motors, matters would have been different.
Later that evening, Mike and Ian sat on the beach in comfortable directors chairs which had cost $26 each at a local hardware in Mikes town. In years gone by they would both have shunned such luxury, but nowadays they enjoyed the indulgence. The pair were drinking strong coffee laced with a liberal shot of brandy, and were feeling philosophical given the bottle of shiraz they had shared at dinner. The current subject was power-boating in a cruising context, and the data gathered from the last twenty-four hours was fresh in their minds.
"I used to think," said Mike, " That powerboats were nautical appliances - something used to get a particular job done in a certain time. But now Im not so certain. That boat of yours is quiet, smooth, economical, and relatively speedy - and there can be no doubting the fact that the ergonomics are better than my sailing boat and Daves." After thinking for a minute or so Mike continued, "But then again, there is a lot to be said for motor-sailing the way Dave and I did today. We avoided being bounced around in the left-over slop when the wind dropped out, but we were able to sail in a satisfying manner when it breezed up about eleven oclock. We had a good sail, while you had to put up with being a powerboat all day long."
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chorili
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15.27
Label:
and,
beautiful,
bill,
Boat Plans,
boats,
fast,
tripps
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| Hinkley Bermuda 40 |
In the last two decades of the Cruising Club of America (CCA) rating rule, William H. Tripp Jr. designed fast, beautiful and innovative sailing yachts. He became known for winning and weatherly centrerboard yawls like the Block Island 40, the Bermuda 40 and the Mercer 44. Many sailors and yacht designers consider them some of the most beautiful boats ever built in fiberglass. They continue to captivate sailors and command high prices in the used boat market today.
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| Mercer 44 |
"The Mercer 44, arguably one of the best-looking stock boats ever built," wrote Seattle yacht designer
Bob Perry. "You can still find Mercer 44s cruising and racing today. They are a marvel of balanced proportions and look as good today as they did in 1959."Tripp was a self-taught designer who came up through the ranks working for other designers, including Sparkman & Stevens and Phil Rhodes.He was a prolific designer. In addition to providing custom racing and cruising designs for many clients he designed production boats for Seafarer, Hinckley, Pearson, Columbia and others. An early advocate of fiberglass, he became known for flush-deck race boats with his distinctive gun-turret dog houses.
As a teenager in the 1960s, Bob Perry considered Tripp to be his favorite designer,
along with Phillip Rhodes."Tripp’s boats had a very distinctive look, with proud sweeping spoon bows, bold sheer springs, long concave counters terminating in almost vertical transoms, and sexy and svelte cabin trunks," Perry wrote in the Nov./Dec. 2011 issue of Good Old Boat Magazine. "You would never mistake a Tripp design for an S&S design. They just seemed to my young eye to have a strength and boldness, kind of an in your face quality. Plus, his boats were consistent race winners."
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| Pearson Invicta 37 |
Burgoo, the Tripp-designed Pearson 37-footer, won the Bermuda race in 1964. At that time it was the smallest fiberglass boat to ever win the race.
"[I]t had all the Tripp trademark design features and it was a very sexy-looking little boat," Perry wrote. "In fact, and I could be wrong, this may be the first Tripp design to have the “gun turret” cabin trunk."
"Bill was the first to put portlights in the topsides as well as opening ports in cockpit sides to improve air circulation and communication below," said Ted Jones
, who worked with Tripp before becoming a boating magazine editor. "He popularized flush decks on small boats (Galaxy, Medalist, Invicta, Mercer 44), and set high standards in hull and rigging scantlings that have been proven over time. He designed boats to stay together under the most difficult circumstances. I cannot recall one of his designs ever being dismasted or suffering structural damage at sea."By the mid-1960s, Columbia, Americas leading builder of fiberglass yachts at the time, approached Tripp to design a fifty footer. He produced the first of the Columbia bubble-topped high-sided boats that are still easily recognizable. In the next six years, he produced thirteen Columbias, including the Columbia 26 MkII, Columbia 34, Columbia 39, Columbia 43, Columbia 45, Columbia 50, and the Columbia 57. The boats are vintage Tripp, but with fin keels and spade rudders.
The C-50 attracted a strong following that still has an active owners association.
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| Columbia 50 |
"The Columbia 50 was a big elegant-looking boat with the same bubble house and long flush deck (of many other Tripp designs)," Perry wrote. "It was a very good-looking boat and it was fast. Seattle’s racing scene was dominated for years by a Columbia 50 called
Six Pack while the smallest class was dominated by a Columbia 26 called
Miller’s High Life."
In 1969, Columbia was the worlds largest fiberglass sailboat manufacturer and Tripp designed a 57 footer named
Concerto, which became the largest production fiberglass boat. It displayed several of Tripps trademark features: an unusually-long and effective waterline, high-aspect ratio sail plan, dual-surface steering system with a keel-mounted trim tab as well as a balanced spade rudder aft. Speed was derived partially from an absolute minimum of wetted surface area, and from the high prismatic coefficient hull design.
In 1971, the racing community adopted the International Offshore Rule (IOR), effectively making every CCA yacht obsolete. Tripp fought hard against the change, but designed a 52-foot IOR boat for Columbia and was looking forward to developing more of his ideas on the new rule. A few months later, a drunk driver lost control of his car, hurtled over the divider on the Connecticut Turnpike and smashed into Tripps Jaguar, killing him instantly. He was 51.
While we usually focus on just one design, I wanted to look closer at a designer first, then at one of his designs in more depth. Stay tuned.
Diposting oleh
chorili
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17.05
Label:
Boat Plans,
boats,
for,
gilbert,
lester,
making,
model,
on,
sail
Model Boat journal
Lester Gilbert on understanding of sail making for model sail boats
Lester Gilbert wrote:
For anyone interested in sailmaking, Ive just finished editing Larry Robinsons "Making Model Yacht Sails" (part 1 only) booklet and have published it as an "international" edition. Ive done this, not to get rich (cos this isnt going to happen to either me or Larry or anyone else connected with this enterprise!), but because Ive spoken to a lot of sailors who want to make sails but dont know the "right" techniques, and who are being misled by incorrect accounts of how this might be done.
A sail block
(Illustration from Larry Robinsons "Making Model Yacht Sails")
From my understanding of sail making, there are two ideas I want to contradict.
The first idea is that you can make sails by accurately cutting a curve on a panel, and then attaching it (stitching, gluing) to another panel. Well, while you might be able to cut a good curve some of the time, your fingers just dont have laser accuracy in them to stick A to B and youll hardly ever obtain reproducible or reliable results. (It might be possible to butt-join the curved edge to another curved edge with a little more reliability, but this doesnt yield what the Equipment Rules of Sailing define to be a seam. Such a sail couldnt be used in sanctioned IOM competition, though it would be OK in a development class.)
The second idea is that you can drape your panels over a "camber board" and get a nice shape that way. Well, let me be clear about what Im knocking here. I take a "camber board" to be a length of curved surface, where the curve is like the surface of a cylinder. In this case, your panelled sail will have exactly the same shape as a single un-panelled sail and, if you wanted a three-dimensional shape, youve wasted your time (though the result certainly looks the part).
Larrys booklet is the only source I know which carefully explains the use and construction of a sail block. I am sure that this is really the only way (in your garage, please, not in some specialist workshop!) to make professional sails, to obtain reliable and reproducible three-dimensional shaping, and to be able to tweak and change your shaping as you learn about the whole business.
(Warning: Yall should know I have ten thumbs and have never made a sail yet. What I have done carefully is to watch and talk to those who do, both professionally and as home builders, and measure the results. Making Larrys booklet available internationally is my way of telling you what Ive learned.)
Bob Wells will be able to ship this within the USA, and I expect that it will also be available from Don Ginthner at GBMY. For worldwide sales, contact SAILSetc. Bob Wells e-mail is "bob" at "islandinet.com", GBMY is "rcsailing" at "gbmy.com", and SAILSetc can be contacted through "sales" at "sailsetc.com".
Ive attempted an analysis of how blocks work on a new page, Sail blocks analysis, and have a new spreadsheet there to help.
Diposting oleh
chorili
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19.36
Label:
Boat Plans,
boats,
distributing,
in,
load,
plywood,
point,
stresses
A very common fault seen in plywood boat construction and design is that of having structural components terminate in the middle of a plywood panel. The most common case is that of thwarts attaching to topside panels, but there are many others. Sometimes the designer or builder will have allowed for this by incorporating other stiffening structures on the outside of the boat, such as spray rails, but often the structure is inadequately supported.
What frequently happens in such cases is that a crack eventually appears where the hardpoint in the structure terminates against the flexible panel.
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| Here is an example of what Im talking about. The two vertical strips of bare plywood on the white topside panel are where Ive been stripping paint in preparation for gluing some reinforcing frames on either side of the thwart. |
In the photo above, the boat had very flimsy plywood hull panels, and the the main thwart (painted grey) terminated against the topside panel without any framing to distribute the stresses. Eventually, cracks will appear around the edges and corners of the thwart, because the plywood can move and flex, but the thwart is relatively immovable. This is a very bad example of design. What I was doing as part of this repair job was to strip paint on either side of the thwart so that I could glue and screw in a pair of frames on each side of the boat to distribute the point loads out into the gunwale and the chine joint.
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Here is the result with the new frames in position. I do not like this boat, but the panel cracking problem has hopefully been solved. |
In my own designs, I try to avoid any point loads from structural components which terminate in the middle of panels - here are a couple of examples: -
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| This is the thwart structure on First Mate. One side of the thwart is supported by the midships ring-frame and the other side is supported by half-frames which run from the inside of the gunwale down to the very strong glass-taped joint between the topside panel and the chine panel. |
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| The stresses are gently distributed out into the structure, and both ends of the half-frame coincide with a very strong part of the boats hull. |
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| This is the internal structure of Periwinkle. Note how once again, the thwart is supported by either a ring-frame or a half-frame with terminates against the gunwale and a strong plank lap joint. Note also how the side deck knees run down to finish on a strong plank-lap joint. |
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| Side deck knees in First Mate, tapered and running down to finish on the very stiff joint between the topside panels and the chine panels. The two cross-braces are just temporary, and help to hold the line of the topside panels fair until the side decks are attached. |
Modern plywood hulls can be wonderfully strong and yet still be light, but the flexibility of the material must be understood if the boat is going to last a long time.
Above is a delightful boat from the English west country, you can look at those lines and know she will run cleanly through the water, yet shes able enough for the sometimes choppy waters of the estuary where she was built to work.
Closer to home this slightly neglected yacht tender resembles a local punt or working boat; stable and designed to carry a heavy load.
