Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors
  #1  
Old 03-26-2017, 10:14 AM
Earl Boebert Earl Boebert is offline
Senior Member
 
Join Date: Dec 2005
Rep: 302 Posts: 297
Location: Albuquerque NM USA
Type Forming

I'm looking for a book or paper that gives a good description of type forming, preferably something by a naval architect. Googling turns up a lot of references to IOR rules, but nothing devoted to the process itself.

I'm hoping to find something I can reference in place of an essay of my own that circumstances are precluding me finding time to write.

Cheers,

Earl
Reply With Quote
  #2  
Old 03-26-2017, 11:59 AM
gonzo's Avatar
gonzo gonzo is offline
Senior Member
 
Join Date: Aug 2002
Rep: 2031 Posts: 11,897
Location: Milwaukee, WI
The only type forming I know of is for working sheet metal. Is that what you are looking for?
__________________
Gonzo
Reply With Quote
  #3  
Old 03-26-2017, 01:05 PM
Earl Boebert Earl Boebert is offline
Senior Member
 
Join Date: Dec 2005
Rep: 302 Posts: 297
Location: Albuquerque NM USA
Quote:
Originally Posted by gonzo View Post
The only type forming I know of is for working sheet metal. Is that what you are looking for?
Er, no. I was referring to the process whereby a set of class rules (usually a box rule) favors a particular design either by accident or intent, and designs converge onto that particular type. When the process ends the class becomes de facto one design.

Cheers,

Earl
Reply With Quote
  #4  
Old 03-26-2017, 03:48 PM
gonzo's Avatar
gonzo gonzo is offline
Senior Member
 
Join Date: Aug 2002
Rep: 2031 Posts: 11,897
Location: Milwaukee, WI
Most class rules are beaten not by good design, but by a legalistic approach. Often, like when Dennis Connors raced a catamaran against a monohull, the race was won in court by lawyers. Therefore, you are better off asking lawyers than designers.
__________________
Gonzo
Reply With Quote
  #5  
Old 03-26-2017, 04:05 PM
Earl Boebert Earl Boebert is offline
Senior Member
 
Join Date: Dec 2005
Rep: 302 Posts: 297
Location: Albuquerque NM USA
Quote:
Originally Posted by gonzo View Post
Most class rules are beaten not by good design, but by a legalistic approach. Often, like when Dennis Connors raced a catamaran against a monohull, the race was won in court by lawyers. Therefore, you are better off asking lawyers than designers.
Oh, sure, but I'm interested in the technical process whereby designers find a unique "sweet spot" in the legal design space and the evolution of the class stops.

Cheers,

Earl
Reply With Quote
  #6  
Old 03-26-2017, 06:05 PM
jehardiman jehardiman is offline
Senior Member
 
Join Date: Aug 2004
Rep: 2040 Posts: 2,261
Location: Port Orchard, Washington, USA
Designers don't find the sweet spot, owners do. Take a look at this post from some time ago. It sums up all the major points.

Americas Cup: whats next?
__________________
A vessel is nothing but a bunch of opinions and compromises held together by the faith of the builders and engineers that they did it correctly. Therefor the only thing a Naval Architect has to sell is his experiences.
Reply With Quote
  #7  
Old 03-26-2017, 06:22 PM
Earl Boebert Earl Boebert is offline
Senior Member
 
Join Date: Dec 2005
Rep: 302 Posts: 297
Location: Albuquerque NM USA
Quote:
Originally Posted by jehardiman View Post
Designers don't find the sweet spot, owners do. Take a look at this post from some time ago. It sums up all the major points.

Americas Cup: whats next?
Perfect. Exactly what I was looking for. Many thanks.

Cheers,

Earl
Reply With Quote
  #8  
Old 03-27-2017, 05:29 AM
gggGuest gggGuest is offline
...
 
Join Date: Feb 2005
Rep: 76 Posts: 760
Location: UK
Type forming is just a somewhat pejorative term for evolution. Evolution towards an optimum design. Its born out of the myth that its possible for rule makers to construct a rating rule that has no perceived optimum. The reason why it happens with racing craft is that the "fittest" - as we are talking about evolution lets say that - is fairly easy to measure because there's one metric: race results.

There's always been a desire in the "boats with lids" racing community that a rating rule should have two quite incompatible aims: one that the best crew should win, regardless of what boat they are in, and the other that better design should be rewarded. That's better in terms of the "fitness" metric of racing success of course. Those who don't like the kind of boat that's optimum complain the rule is type forming.

The contrast, of course, is with non-racing craft where there is no obvious simple metric of success, and as a result all sorts of weird stuff can flourish, since the only real metric of success is "does the owner like it".
Reply With Quote
  #9  
Old 03-28-2017, 01:28 AM
tspeer tspeer is offline
Senior Member
 
Join Date: Feb 2002
Rep: 1673 Posts: 2,068
Location: Port Gamble, Washington, USA
Another thing to consider is in handicap racing, the goal is not necessarily to build a faster boat. Races are won with boats that are not quite as slow as their rating would indicate.
__________________
Tom Speer
Reply With Quote
  #10  
Old 03-28-2017, 04:51 AM
CT249 CT249 is online now
Senior Member
 
Join Date: May 2003
Rep: 215 Posts: 841
Location: Sydney Australia
The other thing is that "box rules" are just as typeforming as measurement rules in many ways. The design of an Open 60 or 12 Foot Skiff is just as driven by their class rules as IOR boats were driven by that rule.
Reply With Quote
  #11  
Old 03-28-2017, 11:13 AM
gonzo's Avatar
gonzo gonzo is offline
Senior Member
 
Join Date: Aug 2002
Rep: 2031 Posts: 11,897
Location: Milwaukee, WI
In PHRF, you can consistently win with a good crew. Get a boat that rates low in the area because it was sailed badly and win a season. Resell at a profit, because people like to buy winning boats, and buy a different design that was sailed badly.
__________________
Gonzo
Reply With Quote
  #12  
Old 03-28-2017, 04:29 PM
gggGuest gggGuest is offline
...
 
Join Date: Feb 2005
Rep: 76 Posts: 760
Location: UK
Quote:
Originally Posted by CT249 View Post
The other thing is that "box rules" are just as typeforming as measurement rules in many ways.
If not more so. But I think its fair to say that in general its not regarded as a problem in the same way. I don't know of a box rule class where there's pressure to attempt to make very differently shaped boats race evenly together.
Reply With Quote
  #13  
Old 03-28-2017, 04:44 PM
gonzo's Avatar
gonzo gonzo is offline
Senior Member
 
Join Date: Aug 2002
Rep: 2031 Posts: 11,897
Location: Milwaukee, WI
No, box rules end up with boats that are very similar. Sometimes, like with foils, there is a radical change. However, in short time, they all end up very similar again.
__________________
Gonzo
Reply With Quote
  #14  
Old 03-28-2017, 05:31 PM
Stumble Stumble is offline
Senior Member
 
Join Date: Oct 2008
Rep: 739 Posts: 1,884
Location: New Orleans
Quote:
Originally Posted by gonzo View Post
No, box rules end up with boats that are very similar. Sometimes, like with foils, there is a radical change. However, in short time, they all end up very similar again.
Any development class if allowed to progress long enough will eventually settle on an 'optimal' solution within the design rules. Once that optimal solution has been developed small incremental progressions are all that will be achieved.

Right up to the point someone makes a major breakthrough and it happens all over again.

The Moth had almost no development for years until it started to foil, then inside just a couple every boat was a foiler, or not racing anymore

The A-Cats are going thru it now, but the development track is a little slower.

TP-52's came out of the gate at pretty much their optimal design and haven't changed much since. In large part because the box rule is so tight.
__________________
Greg Rubin
Captain-Attorney-Boat addict
Reply With Quote


  #15  
Old 03-29-2017, 12:17 PM
Steve Clark's Avatar
Steve Clark Steve Clark is offline
Charged Particle
 
Join Date: Jul 2004
Rep: 163 Posts: 172
Location: Narragansett Bay RI
"Type Forming" is used as a derogatory term for design rules which favor one particular solution over other others that are class legal. For example, the AC keel boat class favored narrow heavy designs over light wide designs.
However, type forming is inevitable if one is intending to organize sailing classes. Simply states, the boats have to be similar enough to provide satisfactory competition. In this explanation, you can see that there is a continuum from the loosest rule " Boats are 18 feet long. Race starts at 2" to the Single manufacturer One Design where anything not provided by the manufacturer is not allowed.
Every other development class rule has some aspects that type forms. A class catamarans have to be catamarans. Moths have to be 11' mono hulls with only one sail. International Canoes are pointed at both ends and have a sliding seat etc.
So while type forming is decried by those who don't think their pet idea is being arbitrarily excluded, one has to accept that every class has to be type formed to some extent simply to be identifiable as a class.
SHC
__________________
Beatings will continue until morale improves.
Reply With Quote
Reply



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Shell Plate Expansion and type of forming process Navdes_E Boat Design 2 02-08-2011
02:07 PM 
cold forming skill Brian.Lin Boatbuilding 0 03-24-2010
02:56 AM 
6082 forming Guest62110524 Metal Boat Building 10 06-21-2009
07:17 AM 
Roll forming aluminum dick stave Metal Boat Building 0 02-10-2008
11:34 PM 
Hull Forming Material Fanie Boat Design 8 10-28-2007
05:00 AM 

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.

All times are GMT -5. The time now is 06:04 AM.


Powered by: vBulletin Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2017 Boat Design Net