Showing posts with label like. Show all posts
Showing posts with label like. Show all posts
Monday, 9 April 2012
How to build a boat like gibbs
How to build a boat like gibbs is without a doubt probably the content under the now Young children and can on the history the search engines That allows you to furnish invaluable advice to the visitors get made an effort to search for a best meaning illustrations or photos all over How to build a boat like gibbs Along with below you will definitely discover currently, these types of pictures happen to be used within the biggest source of information.
How to build a boat like gibbs - it's already been submitted with the expectation that will we can easily simply definitely really encourage currently employed to help persons. This text are able to help being useful resource when you're baffled to find the correct manual The How to build a boat like gibbs discussions may perhaps be your foremost method to get used on the project prepare, the way it possesses its very own approach will probably think far more content How to build a boat like gibbs - Very helpful for you personally so you hoping acquire a dependable resource which usually can assist you acquire determination while not frustration. bear in mind so that you can take note of these pages, since probably some day you will want the idea rear seeing that ones inspirational thoughts.
Tuesday, 10 May 2011
Steps and second steering stations on smaller boats nope dont like them
All too often advances in technology or performance comes with a price, and a step hull is no exception. Step hulls are much different from the deep V hulls most are familiar with, and come with their own special jargon that contains words such as chine walking, snapping, rolling, hooking, step tripping, porpoising, turn blow outs, and many others, none of which have successful boating connotations. The point is that all boat hulls are compromises, and step hull vessels have more of them than most, particularly for the less than experienced boater.
From a design viewpoint, a well implemented step hull can improve the hull efficiency by up to about 15%, but like all things in life, the laws of physics extracts a price for this. The principle of reducing the wetted surface of the hull using steps, gives the hull markedly different handling characteristics, especially when contrasted with most boaters personal experience with traditional deep V design hulls. The area behind each step may need to be be ventilated with air, and having a wave, or turning the boat in such a way that the ventilation slots get closed by water can cause bad things to happen such as abrupt slowdowns, the back end of the vessel breaking loose, or worse. Improperly trimming, and or letting off on the throttles during a turn can also have severe, and deleterious effects. Design of a stepped hull is extremely complex, particularly if more than one step is incorporated into a hull, and small errors can have dramatic impacts on handling. Designing these hulls so they operate consistently over a broad range of speeds takes experience, good computer modeling software, and a lot of time.
I know from personal experience that in too many cases, step hull buyers are given little if any instruction by the dealers and private sellers, and many, (but not all) owners manuals, if they exist at all, are woefully deficient in clearly explaining the handling characteristics of these hulls. It's not that the hulls are bad, they work exactly as they were designed to, it's just that they are very different from a deep V hull in their handling, and need to be treated that way. These improvements in performance come with requiring even more vigilance, and understanding about how these boat hulls really work. The step hull driver should always be prepared for the unexpected to happen, and should clearly understand exactly how their boat works. All too often the owners don't have a good understanding of why these hulls are truly different, and this is when bad things can, and have tragically happened. As for me, despite the performance gains, I still prefer the more traditional, predictable, safer, and more docile deep V hull. I don't need any additional boating adventures in my life. I have enough already, despite any savings, or performance gains there might be. But in a race, if I was a trained and experienced professional, you betcha, but you "still half to know the territory". (Stolen from Professor Harold Hill.)
You can find an excellent paper by Kobus Potgieter on how a step hull really work here.
Now on to second steering stations on smaller boats. This another thing I am suspicious about, and I generally dislike. In the fervor to see the large fish, or the weed lines, I have the sense that other important things are often being overlooked, like the vessels inherent stability. In the robot business we always worried about the moment on a robots arm. This was a simple formula which goes, moment = length of the robots arm times the weight of the load. A simple example of this is to pick up a concrete block, and let it hang from your arm, see that's not to bad is it? Now holding the same block, lift you arm so the block is now being held out at arms length. If you can do it, it will be excruciating. Welcome to the world of moment on a very simple scale.
The second station your looking at is mounted on a 29' boat. I am guessing the structure has to weigh at least 250 lbs. There is room for two passengers on top, and lets say these are skinny guys that weigh about 150lbs each. We now have a total load of 550lbs, that is now about 7 feet or more above the vessels center of gravity. Now list the boat about 20 degrees to starboard. That equates to about 3' so the moment is now 3 * 550lbs = 1650lbs. Now tip the boat 40 degrees, (6') and the moment is now a whopping 3300lbs, over a ton and a half of weight, and we haven't even considered the momentum involved yet. You should not be surprised if the vessel could not recover, and the second station, with passengers get to meet the seawater up close, and personal.
Only a few manufacturers actually offer second stations as a factory option on smaller boats, and the hope is that the designers have factored the upward shift in the vessel center of gravity into their designs, and I know that several of the ones that do provide the option did consider this loading in their design. The boat you are looking at never had a factory option for this. It's a custom built package, and I seriously doubt that anyone thought much about the impact on the vessel.
There are many more sophisticated ways to calculate moments, their impact on a vessels center of gravity, and this was a simple way of demonstrating how quickly the numbers can add up with an increasing heeling angle. If you want to do this to your boat, discuss it with the manufacturer, and get an opinion from a naval architect, especially if you're adding it to a stepped hull vessel. All boats typically work well on a nice day running on flat water, it's when you're caught by surprise, that you have to worry about how well your vessel will really perform.
Only a few manufacturers actually offer second stations as a factory option on smaller boats, and the hope is that the designers have factored the upward shift in the vessel center of gravity into their designs, and I know that several of the ones that do provide the option did consider this loading in their design. The boat you are looking at never had a factory option for this. It's a custom built package, and I seriously doubt that anyone thought much about the impact on the vessel.
There are many more sophisticated ways to calculate moments, their impact on a vessels center of gravity, and this was a simple way of demonstrating how quickly the numbers can add up with an increasing heeling angle. If you want to do this to your boat, discuss it with the manufacturer, and get an opinion from a naval architect, especially if you're adding it to a stepped hull vessel. All boats typically work well on a nice day running on flat water, it's when you're caught by surprise, that you have to worry about how well your vessel will really perform.
Saturday, 16 October 2010
Local boats I like Route 66
This is the first of the "boats I like series." These are vessels that catch my wayward and mercurial eye. Since Sarasota has such a diverse boating community, these can range from something stashed away in a garage, to vessels hidden in plan sight in the many local marinas and canals. The one thing they have in common is their uniqueness, and personal appeal to me. With most of these boats, I don't know the owners, and have never boarded them. We're starting today with "Route 66" that is currently residing in the Longboat Key Moorings marina.
You can miss the nearly 80' of elegantly crossed braced mast and swept back spreaders on Route 66 designed by B&R Designs (Lars Bergstrom, and Sven Ridder). If a sailor isn't familiar with these names, just look look up at the Windex atop your mast. This is one of their many sailing innovations.
Lar's, an experienced pilot passed away in 1997 due to a tragic powered sailplane accident. One of my favorite possessions is one of the carbon fiber water tank test hulls of Route 66 I bought when his Sarasota facility was closed and it now hangs from my living room ceiling.
Route 66 is the product of the many lessons learned from the Warren Luhrs's ocean racing sailboat children, Tuesday's Child, Thursday's Child, and Hunter's Child.
Hunter's Child's hull shape was an improvement on Thursday's Child's designed by both Paul Lindenburg, and Lars Bregstrom, and built by B&R Designs. Thursday's Child was already a big winner, and broke the New York, to San Francisco record held by the clipper Flying Cloud since 1854, along with other records.
Two things are of note are here. Hunter's Child, and Route 66 have semi-circular hull sections over most of the their length. This allows the hull to heel with out changing its waterline shape.
This is also I believe one of the tallest of what is now known as the B&R rig used on a cruising sailboat. Lars Bergstrom had been evolving what would eventually become known as the B&R rig years earlier. The oldest example I have found to date is the B&R designed Tailwind 38 built by Hurley Maine in the UK during the early seventies.
If you look closely at the pictures you can see the B&R rig on both Thursday's Child, and Hunter's Child. Lars Bergstrom designed the rigs for all three of the Child boats, and spent enough time sailing them to decide what could be improved. In the case of Thursday's Child, he and Warren Luhrs both sailed her to Plymouth England for the start of the 1984 OSTAR race. Lars also crewed for Warren Luhrs on Thursday's Child during the record breaking New York to San Francisco run. I'm sure the 80 day 13,000nm plus run gave him plenty of time to contemplate the vessel's rigging and design.
I never found a picture of Tuesday's Child, but the other two Child boats have struts running from outboard to the mast. These are the two side legs of what would eventually become the tripod on Route 66, and used later on some Hunter boats. Both vessels also have the distinctive swept aft spreaders with the diagonal cross bracing. The small oddity in all of this is Hunter's Child had a backstay, while the rig on Thursday's Child did not.
Other design innovations carried over from the Child boats design efforts that were applied to Route 66 were the adjustable canting rudder, and water ballasting, The air slot that feeds air to the rear of the Route 66's hull reducing friction, was retrofitted into Hunter's Child after the fact.
Route 66 is a powerful cruising boat with an extreme racing pedigree and is capable of speeds in excess of 20 kts. With the simple cockpit layout, however I think she would be very easy to sail.
A barn door Park Avenue boom with no sail tracks, and a furling head sail. The bow has two retractable poles one to push the anchor rode out and away from the bow, and the other for an asymmetric spinnaker. All lines and sheets go to the cockpit.
Route 66 is a stunning and extraordinarily creative design. She is gorgeous to my eyes, and like her earlier predecessor Thursday's Child, she has a long way to go yet.
To learn more about Route 66, here are some additional links.
Route 66 home page.
Comments By Lars Bergstrom on the design.
http://www.yachtroute66.com/YW.html
Route 66 is the product of the many lessons learned from the Warren Luhrs's ocean racing sailboat children, Tuesday's Child, Thursday's Child, and Hunter's Child.
Hunter's Child's hull shape was an improvement on Thursday's Child's designed by both Paul Lindenburg, and Lars Bregstrom, and built by B&R Designs. Thursday's Child was already a big winner, and broke the New York, to San Francisco record held by the clipper Flying Cloud since 1854, along with other records.
Two things are of note are here. Hunter's Child, and Route 66 have semi-circular hull sections over most of the their length. This allows the hull to heel with out changing its waterline shape.
This is also I believe one of the tallest of what is now known as the B&R rig used on a cruising sailboat. Lars Bergstrom had been evolving what would eventually become known as the B&R rig years earlier. The oldest example I have found to date is the B&R designed Tailwind 38 built by Hurley Maine in the UK during the early seventies.
I never found a picture of Tuesday's Child, but the other two Child boats have struts running from outboard to the mast. These are the two side legs of what would eventually become the tripod on Route 66, and used later on some Hunter boats. Both vessels also have the distinctive swept aft spreaders with the diagonal cross bracing. The small oddity in all of this is Hunter's Child had a backstay, while the rig on Thursday's Child did not.
A barn door Park Avenue boom with no sail tracks, and a furling head sail. The bow has two retractable poles one to push the anchor rode out and away from the bow, and the other for an asymmetric spinnaker. All lines and sheets go to the cockpit.
Route 66 is a stunning and extraordinarily creative design. She is gorgeous to my eyes, and like her earlier predecessor Thursday's Child, she has a long way to go yet.
To learn more about Route 66, here are some additional links.
Route 66 home page.
Comments By Lars Bergstrom on the design.
http://www.yachtroute66.com/YW.html
Subscribe to:
Posts (Atom)
