TP52s

Steve, your comment may be based on a recent edition of Chapmans. Earlier editions did not make the destinction of side to side movement and nothing in print other than the latest edition of Chapmans has done so AFAIK. It is a hoot to compare what is written in Chapmans (is it the 62nd edition,) anyway the latest, with what is in earlier editions. You can just see that a big technology change was about to happen involving movable ballast and folks were struggling with it.

Chapmans is not well respected by sailors on the West Coast of the USA. I spent most of my life power boating, so I can not do without it, but I think when Chapman tried to call a sloop that did not have a bow sprint a knockabout, he lost his sailboat readership. It hasn't really recovered, and we still call sloops without sprits sloops.

Movable ballast means movement on and off the boat as well as from side to side.

The Minitransats and I expect other ocean race boats are designed to rules that limit the amount of water ballast that can be carried. Hence we get multiple tank systems and pumping from side to side. That complexity is not needed in boats that are not compromised by design rules and especially in designs using other forms of movable ballast, like swing keels and retracting fins. Furthermore the rules require that the ballast be positioned as if it were rail meat, high not low in the vessel.

MacGregor Yachts took responsibility for water ballast in sloops and in all water ballasted vessels produced except the X - as you state - did put the ballast on the center line. In the Mac26x they placed the ballast outboard aligned with the rudders.

The model they are currently producing has gone back to the centerline arangement. An indication of influence by the 2002 court case IMO.

In all models with centerline water ballast you are not to operate the boat unballasted.

In the X, the manufacturer intends you to both sail and power unballasted as well as ballasted by moving the water off the boat when appropriate, for racing in light air and down wind, and filling when needed for heavy weather and upwind operation.

I have coined the term fixed water ballast for the kind of water ballast used in all the MacGregor models except the Mac26x. Chapmans is correct that fixed water ballast is not comparable to what is used on minitransats and Open 60s. I certainly agree that they do a public service in pointing that out. But the Mac26x was never intended to be operated as a fixed water ballasted vessel.

In anycase the notion of pumping water from side to side as defining movable ballast is something that came up only in the last edition of Chapmans about 2 years ago. It is a new notion and an incorrect one when you realize that water ballasted vessels benefit by having ballast on both sides of the vessel owing to the stable forces similar to a twin keel vessel. The less a boat staggers the better its sails can propell it forward.

Perhaps you know more? Do you have a source other than Chapmans for the notion that movable ballast is only from side do side? Are you aware that many of the canting keels can be move forward and back as well as from side to side?

What the canters can not do is move weight off the boat. This is the significant advantage that water ballast has over canters. Of course, outside of an artificial design rule, you can have both kinds of ballast and some of the Open 60s do. That was a nice Open 60 photo.

I am taking off for my sailboat right now. Do keep up the banter without me. ISee you monday.

Oh chew on this if you can. The idea off putting a centerboard on the centerline, which is the most important structural area of a hull, came about as the result of design rules. Prior to that many vessels had foils off centerline. The centerline arrangement was expensive.

 

Who TF is Chapman (apart from the "ap Chapmann" of 1600's fame) ? My comments are based on 25 years in the business, and in the design of 4 water-ballasted or canting-keel Open Class boats. Your comments are based on what? Being an "armature" designer? Better cheque your spell-chequer.

I do have a 1950's copy of Chapman's "Piloting, Seamanship and Small Boat Handling" which my grandfather gave me years ago. Izzat the fella? If so, then I'm afraid I stopped looking in their for wisdom about 30 years ago.

If you an prove that, I'll eat my hat. which ancient Chinese manuscript described the rules under which their river junks raced? It is generally accepted that the Chinese did it first, although the Americans began to use them during colonial times. The British Navy exoperimented with them in the late 1770's (1774 onwards). Don't try to tell us that they moved the centreboard away from the most important structural member in the boat. It is much easier to get a watertight centreboard case if it is through the keel than it is to plonk one off centreline through the planking. Now, if you are talking about fibreglass boats, wel... I rest my case.

Steve

 

Wrong again! You must have a CE mark to enter EU markets.

You do not appear aware that Farr doesn't sell or produce molds.

No - you can't even get the basics right!

 

No. Ballast that is moved on and off the boat is removable ballast.

 

"I did run a couple of departments at City University for a few years, is that what you are getting to?"
-No, I wanted to know if you have any training or practical nav.arch. experience.

"...does Farr have any naval architect credentials? Does the designer of the Melges?"
-Why, yes they do. Practical design and sailing experience, successful designs, and very highly trained people that work in their offices (I know some of them personally, and have worked with them).

"I am an armature boat designer..."
-I think you might mean either amateur or armchair.

"Are you a Naval Architect from MIT? What is your beef? You are aware that Naval Architects are expected to know diddly about sailboat design?"
-Yes, I am a nav.arch., graduated with honors. as well as MS in structural engineering, with A average. I have 15yrs of professional experience, nearly 100,000 miles blue-water cruising and racing experience, blah blah blah. My beef is trying to figure out your beef. Maybe I'm just dim, but I can't really decipher what it is you're bitchin about. Perhaps a bulleted list of one-line grievances might help? Then we can take them to the UN security council.

Undergrad nav.arch. programs require engineering training on all water craft, to understand the physics to decipher the design issues into a solvable problem. Nav.Archs. are not required to specialize in yacht design, but can if they wish. Any competent nav.arch. grad could grasp the issues of yacht design quite readily. I guess the key word is competent- competency is not necessarily limited to someone with a degree, but other practical credentials sure do lend credibility.

 

I don't want to complicate this subject too much for you ghetto, but ballast does not damp the boat's motion as a keel does. It increases the vessel's mass and moment of inertia, which slows its response to external forces and moments, but the ballast itself does not damp the boat's motion. There will be some damping from the additional hull immersion and wetted surface, but this effect is small compared to the higher level of inertia. I assume by "stable" forces you mean stabilizing forces, since the term "stable forces" has no relevant meaning that I can see.

And even if there is ballast on both sides of the boat, the inertial behavior of a fixed distribution of ballast does not change when the boat heels. The ballast's righting moment will depend on the position of its center of mass relative to the boat's center of flotation, but not on its distribution. And it does not involve any interaction between the ballast and the water. I assume you know ghetto that ballast is a gravitational and inertial mechanism and not a hydrodynamic one.

So unfortunately ghetto, your twin-keel analogy of ballast is entirely incorrect. In addition to the fact that your analogy has no merit at all, it has the further disadvantage of having absolutely no relevance whatsoever to the question of movable ballast. Call me a purist, but it seems to me that the term "movable ballast" should refer to ballast that is actually movable and not just dumpable.

 

Wrong.

 

Go check out the interview on TP52s in Scuttlebutt........seems that some people reackon they go OK....in fact better than OK.....aside from all the tech stuff it seems to me that if its fun to sail and you get a buzz from it, its GOOD.
Is there a seperatist attitude between east/west coast sailing in US or is Frankie just stirring the pot.Damn hes good at sparking reactions then spirraling off in a different direction just to fire up another set of reactions.
Just agree with him all the time and see what happens,could be interesting.
K4s
.ps..You dont really need to believe

 

Oh by the way,I think the true purpose of this thread is to get as many hits as possible which is exactly what happened in other forums.Guess Im helping to get the numbers up with this post.Wont be long before he starts to brag about the number of hits!Just you wait and see.
K4s

 

You guys are fighting an unwinnable battle. The easiest way to be rid of the garbage this guy spews is ignore him. He does go away.
I hate to see intellegent people lose their cool over this guys noise. It is a waste of perfectly good typing time and thought that could be put to better use teaching somebody who cares what the right anwers are....me for one!

 

I promise this is the last time I will read this thread

It's an over used and mean saying but applicable.
Winning an argument in a chatroom is like winning a gold at the special olympics.

 

Good morning Boat Designers.

Steve,

I do have a 1950's copy of Chapman's "Piloting, Seamanship and Small Boat Handling" which my grandfather gave me years ago. Izzat the fella? If so, then I'm afraid I stopped looking in their for wisdom about 30 years ago.

Wow, 1950's. I would hold on to that pup. Chapmans I guess isn't well respected by any sailboat group. The latest volume is 64. It is a mammoth. I recon it is only worth reading after reading Royce's Sailing Illustrated Volume I, a book that sadly is not carried in the finer book stores near and in the sailing museum state RI. The idea of warning owners of fixed water ballasted vessels not to sail unballasted is a good one and I think that is why Chapman's 64 edition contains the confused material. If the vessel is meant to be sailed unballasted or ballasted then we have a vessel more similar to a minitransat or Open 60. A "removable ballast" vessel. Is someone taking notes. Good stuff. A removable ballast vessel might include ICON or any boat that changes bulbs to match race day conditions. It could also be any boat that is allowed to leave crew members on the dock before a light wind race. If the ballast can be removed during a race, however, it really is movable ballast and superiour to canters, for long races where you can expect periods of little wind. Again, there is nothing stopping one from having both.

Anything in your 1950 book about leeboards?

I stand by my statement that the idea of putting a centerboard on the centerline, which is the most important structural area of a hull, came about as the result of design rules.

If you an prove that, I'll eat my hat. Which ancient Chinese manuscript described the rules under which their river junks raced? It is generally accepted that the Chinese did it first, although the Americans began to use them during colonial times.

Hold on to your hat. However, you will be able to find design rules for the early America's Cup racing which specifically allow centerboards when on centerline. That specificity implicitly excludes them from off centerline locations. Yes, it is generally recognized that centerboards were invented in China. I have been saying that when Europeans first began settling the Americas, they were obliged to utilize the ports long established there by the native American people. This forced them to look at centerboards.

The British Navy experimented with them in the late 1770's (1774 onwards). Don't try to tell us that they moved the centreboard away from the most important structural member in the boat.

The all weather ports in the Americas, for the most part, were to shallow for the deep draft vessels used by the British. Advancement in China's centerboard was an absolute necessity for Europeans who wished to trade in the Americas and in many ways centerboard designs represent the best of American boat building innovation. If you were experimenting, would you not first fashion a board on the lee that did not pierce the hull, IE a lee board. Then would you not think about the shape that the hull presents to the water when underway and next put the board in the center of that area. IE off centerline. Would you not do this before compromising the most important structural area of the hull? The economics of this are: to discourage centerboard designs but appear to allow them, design rules were created that made centerboards expensive because they had to be right at the spot where poor implementation would cause loss of hull integrity. Spots just a few inches from centerline were not allowed. Oh we are chatting large vessels here like Maria, the first American racing machine. Maria sported a small steering centerboard well aft as well as a 12 foot tiller. And we are not making a distinction between swing style centerboards and daggerboards. I have not figured out how that destintion was ever made except to speculate that owing to the Bayliner case it was best to come up with a name for a board that did not sound like centerboard, because centerboard had all these unfavorable child killing connotations (see below).

It is much easier to get a watertight centreboard case if it is through the keel than it is to plonk one off centreline through the planking. Now, if you are talking about fibreglass boats, wel... I rest my case.

The case was rested in 1996 when a long court case was resolved involving the centerboard keel structure of a Bayliner Buccaneer 180. Water entered the bilges unnoticed and an expert testified that the water could have entered through the centerboard slot. The water contributed to a capsize and the death of panicked children. The vessel did not sink. Bayliner was believed responsible for not adequately explaining that water could enter the boat by way of the centerboard slot. See http://www.law.emory.edu/6circuit/may96/96a0143p.06.html. This is only one example of design by court case. Until the case was resolved, US Sailing and other groups could claim fixed keels better and designers could ignore the speed advantages of retractable foils in monohull race boats.

The Bayliner case is a significant case for designers.

First Bayliner was and today is considered a powerboat manufacturer. As we discussed earlier, this notion that NAs design powerboats and know diddly about sailboat designs was supported by taking Bayliner to task on the Buccanner. Only Bayliner had hired a sailboat designer for the Buccanner. Most folks do not know that. Read the case.

Second centerboards are not normally housed in a watertight case. It is for that reason they were portrayed as dangerous. Of course the canting keels are not usually in watertight cases either. My boat has the centerboard in what is really a hollow. The case or hollow is actually part of the hull. I bring this up by way of noting that TP52 supporters had proposed allowing hollows in the 40 foot design, but only forward of midship. Hopefully we can discuss that later. At this point in time doesn't appear that any 40 footers will be built. Farr has a design but there is no interest in replacing the Farr 40s on the east coast of the Americas.

BTW, there is no battleground being laid out on this forum. I know there are various viewpoints on design and on the profession. Apparently the first to be recognized in the US as a professional yacht designer was a Dane like Søren Flening. It would be interesting to look at Louis Winde, who was educated in Denmark, to see why his work was professional. He worked out of Boston around the 1850s.

I am advocating movable ballast and retractable foils as the future of yacht design and claiming highly weighted bulbs on the ends of thin fixed foils foolish. But I recognize I am not educated in boat design. I do think these TP52s represent a great opportunity to learn because there are only 10 owners to piss off and because the GP RWP obsoleted them, but there is still a lot of press. It is the kind of opportunity that can not be dismissed by serious professional and amature designers. Lets not think of our posts here as an unwinnable battle to change a point of view as DGreenwood states. Lets think of the posts as an oportunity to teach and learn. Forums like Sailing Anarchy specifically state that they are not about education. This forum is. Huzzah.

 

K4

Oh by the way,I think the true purpose of this thread is to get as many hits as possible which is exactly what happened in other forums.Guess Im helping to get the numbers up with this post.Wont be long before he starts to brag about the number of hits! Just you wait and see.

Another milestone 4,000 hits. K4, could be correct. I do not really know. Seems like folks view to see what others have said about my posts rather than what I have to say. It use to be that email could be relied on for feedback. But with spam one never knows. I got this message last week:

DEAR SIRS
WHEN YOU HEEL INTO THE WIND IT LIFTS YOU UP AND THE FIXED MAST PUSHES
YOU DOWN. ALSO THE WINDSURFERS WITH MORE LATERAL RESISTANCE AND A SLOOPSAIL RIGG I FOUND MORE EFFICIENT. ;
S. NEWMAN DARBY, INVENTOR OF WINDSURFING

Spam or real? I had thought it spam until recently hearing that a sailboard has retaken the speed under sail record. For background, If you take a sail board, put a cabin on it, put lifting fins under the rider in the aft, you have a planing race boat. But that is a different topic. I only brought it up to encourage folks to send email to mighetto@eskimo.com, but recognize that I get many emails that are spam like and tend to just let those go. If the post looks ligitimate, I am addressing it here. Thanks.

 

Søren Flening

Lets try to get the basics correct. Where did I go wrong? Owners that can show they have a boat that entered EU waters prior to 1998 are grandfathered in. They can get exemptions from the CE marking rules. Is it boat specific rather than model related. Is that what you mean?

Thanks