Modern Hull forms and Motion Comfort - Page 19 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Boat Review and Purchase Forum > Sailboat Design and Construction
 Not a Member? 


Like Tree60Likes
Reply
 
LinkBack Thread Tools
  #181  
Old 04-15-2013
Senior Member
 
Join Date: Dec 2012
Location: new england
Posts: 1,698
Thanks: 31
Thanked 30 Times in 27 Posts
Rep Power: 2
outbound is on a distinguished road
Re: Modern Hull forms and Motion Comfort

As some one who has actually done some neurological science with a prior teaching appointmnt at the Harvard Medical School I have no problem saying I stand in awe of Mr. Perry. Paulo shows us wonderful boats but Mr. Perry draws boats that are also quite reasonably fast, extremely safe and most important have that organic something that makes them someplace I want to live not just survive on as I continue the voyage foward. That's an artist as well as a great engineer.
It is said- It's more dangerous to not know what you don't know then to have insufficient knowledge as if you are truly alive you can learn.
__________________
s/v Hippocampus
Outbound 46
Reply With Quote Share with Facebook
  #182  
Old 04-16-2013
One One is offline
Always tired
 
Join Date: Mar 2013
Posts: 235
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 2
One is on a distinguished road
Re: Modern Hull forms and Motion Comfort

Quote:
Originally Posted by SloopJonB View Post
I was thinking more along the lines of respect than "awe".

I guess we mere peasants just don't have the subtlety of thought or understanding to grasp the concepts you seemingly have at your fingertips.

I mean, a mere 40 years of sailing, boatbuilding and studying design isn't that much of a base of knowledge is it?
When did I say it wasn't much of a base of knowledge? I accused you of not understanding what I wrote - that has no bearing on how much experience you have. And did I call you a peasant? No, I explained in no uncertain terms where you went wrong, and how you went wrong.

As for "respect": I do have respect for when respect is due. But regardless of who I'm talking to, I get annoyed when people continue to misunderstand, or worse; misrepresent what I'm saying. And while I got annoyed with Bob, I'm glad I was finally able to make it clear we were talking about the same thing, and that I wasn't disagreeing with him. I'm not saying it is his fault per se, I'm saying I wasn't able to make it clear to him at first.

You then come along and demand respect on his behalf, utterly unaware that we were "clear" with each other, that there weren't actually a disagreement.

Edit/add:

Outbound,
Why do you have a problem with me using a figure of speech? Do I have respect for Bob's know-how and skill set - of course. Do I think it's "artistry" - of course not. It's about using one's knowledge and skills and apply them. Some things will be "intuition", but since intuition is based on one's knowledge base, it still comes down to being skillful.

And, as for this:
Quote:
Originally Posted by outbound View Post
It is said- It's more dangerous to not know what you don't know then to have insufficient knowledge as if you are truly alive you can learn.
If you're implying that I suffer from the Dunning-Kruger effect (look it up), you couldn't be more wrong. I'm not claiming to know more than Perry about boat design. I have made it clear that I attempted to explain things with a different wording, and in 3d rather than 2d. That doesn't mean we weren't talking about the same thing, nor that we were disagreeing.

Last edited by One; 04-16-2013 at 12:40 AM.
Reply With Quote Share with Facebook
  #183  
Old 04-16-2013
Resolute_ZS's Avatar
Kayaker/Dreamer
 
Join Date: Oct 2012
Posts: 122
Thanks: 2
Thanked 1 Time in 1 Post
Rep Power: 2
Resolute_ZS is on a distinguished road
Re: Modern Hull forms and Motion Comfort

Can we take the attitudes to PM, please, instead of crapping up a perfectly decent thread? I think out of the last few posts, Jeff_H's is the only one relevant to this otherwise useful discussion.

Jeff - thanks for starting another thread for that. I'm looking forward to seeing what comes of it.
Reply With Quote Share with Facebook
  #184  
Old 04-16-2013
smurphny's Avatar
Over Hill Sailing Club
 
Join Date: Feb 2009
Location: Adirondacks NY
Posts: 2,853
Thanks: 55
Thanked 63 Times in 61 Posts
Rep Power: 6
smurphny is on a distinguished road
Re: Modern Hull forms and Motion Comfort

Quote:
Originally Posted by Resolute_ZS View Post
Can we take the attitudes to PM, please, instead of crapping up a perfectly decent thread? I think out of the last few posts, Jeff_H's is the only one relevant to this otherwise useful discussion.

Jeff - thanks for starting another thread for that. I'm looking forward to seeing what comes of it.
Indeed, please refrain from ego-induced belly bucking in an extremely interesting discussion which includes one of the world's most respected yacht designers. I, for one, would like to learn from the discussion.
__________________
Alberg 35: With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship.
Reply With Quote Share with Facebook
  #185  
Old 04-16-2013
Senior Member
 
Join Date: Dec 2012
Location: new england
Posts: 1,698
Thanks: 31
Thanked 30 Times in 27 Posts
Rep Power: 2
outbound is on a distinguished road
Re: Modern Hull forms and Motion Comfort

Given this generation of boats float on the water instead of in it but still need to cope with a perturrbed water/air interface one would think aspects of the structure would be subject to frequent loading/unloading cycles of a severe degree. Kind of like a Donzi skipping over chop versus a Kady Krogen. Given weight reduction and stiffness are at a premium to enhance speed with many of the the construction elements non plastic ( engineering wise not chained hydrocarbon deriviatives) and brittle one wonders about usable life. Surely they survive more hours sailed and more miles in a single ocean race than even a cruiser decades old but cruising boat's structure is rarely loaded anything close to it's point of designed failure. Furthermore, carbon cracks when oveloaded and cored structures with load on skins fail catatrophically. Metal and even GRP is more plastic in these settings. Wonder if this presents another design difficulty for th N.A.s of the pogo's and like vessels. Although this hull form has been popularized for ~a decade wonder if there is any feedback on how these boats fare down the road given the abuse a cruiser endures.
__________________
s/v Hippocampus
Outbound 46
Reply With Quote Share with Facebook
  #186  
Old 04-16-2013
PCP's Avatar
PCP PCP is offline
Senior Member
 
Join Date: Dec 2004
Location: Portugal, West Coast
Posts: 16,166
Thanks: 21
Thanked 96 Times in 80 Posts
Rep Power: 10
PCP will become famous soon enough
Re: Modern Hull forms and Motion Comfort

Quote:
Originally Posted by outbound View Post
Given this generation of boats float on the water instead of in it but still need to cope with a perturrbed water/air interface one would think aspects of the structure would be subject to frequent loading/unloading cycles of a severe degree. Kind of like a Donzi skipping over chop versus a Kady Krogen. Given weight reduction and stiffness are at a premium to enhance speed with many of the the construction elements non plastic ( engineering wise not chained hydrocarbon deriviatives) and brittle one wonders about usable life. Surely they survive more hours sailed and more miles in a single ocean race than even a cruiser decades old but cruising boat's structure is rarely loaded anything close to it's point of designed failure. Furthermore, carbon cracks when oveloaded and cored structures with load on skins fail catatrophically. Metal and even GRP is more plastic in these settings. Wonder if this presents another design difficulty for th N.A.s of the pogo's and like vessels. Although this hull form has been popularized for ~a decade wonder if there is any feedback on how these boats fare down the road given the abuse a cruiser endures.
There is some confusion here: The Pogo is not a Carbon boat. The Class 40 racers are not also Carbon boats, Carbon is specifically forbidden by the rules. The idea of the Class is to provide a fast and inexpensive racer.

Regarding the fragility of the cruising Pogo, that use the same hi-tech building techniques used on the Class 40 and mini racers, there is nothing to fear.

They have been making race boats for the last 26 years and the boats are on the water, racing or cruising after many transats and some circumnavigations. In fact the Pogos are known to be incredibly though.

Look here and you will see how much:



Pogo is among the builders with more experience building light and strong sailboats. It is a passionate firm that started with doing mini Racers. His boss won in the 1999 mini transat race on the series class, on a Pogo, of course.

He is not young anymore but last year, just for the Fun of it, made with the owner of one of the first Pogo 50 (cruising boat) the ARC in the racing class and they were the third boat to arrive after a 40class racer and close to a Swan 80, being faster than a lot of much bigger boats

Of course they did not won anything (they were 5th on Handicap) because as I have said the handicap of the boat is horrible. The boat is not made to race (it has a swing keel) but to cruise fast and that they have done, crossing the Atlantic in 8 days and 20 hours. A Pogo 12.50 on the same ARC was also among the first to arrive crossing in 9 days 21 hours.

Regards

Paulo
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by PCP; 04-16-2013 at 08:39 PM.
Reply With Quote Share with Facebook
  #187  
Old 04-16-2013
Senior Member
 
Join Date: Feb 2012
Location: New Orleans Louisiana
Posts: 1,927
Thanks: 6
Thanked 43 Times in 41 Posts
Rep Power: 3
Stumble is on a distinguished road
Re: Modern Hull forms and Motion Comfort

Outbound,

From the best data I can find, carbon/epoxy actually has a flatlining S-N curve, like steel, not a liner one like aluminium. So as long as the design is done properly fatigue life can be controlled to near infinite levels. Even a more conservative assumption would place it at an order of magnitude better than aluminium in terms of fatigue properties.
__________________
Greg Rubin
Attorney
Reply With Quote Share with Facebook
  #188  
Old 04-16-2013
Senior Member
 
Join Date: Dec 2012
Location: new england
Posts: 1,698
Thanks: 31
Thanked 30 Times in 27 Posts
Rep Power: 2
outbound is on a distinguished road
Re: Modern Hull forms and Motion Comfort

thanks- I stand corrected. Would think given less weight even less load so even more durable. Knew the restriction on carbon was asking a more general question which was answered directly by stumble and also included in your post.
__________________
s/v Hippocampus
Outbound 46

Last edited by outbound; 04-16-2013 at 09:13 PM.
Reply With Quote Share with Facebook
  #189  
Old 04-18-2013
grumpy old man
 
Join Date: Apr 2011
Posts: 3,647
Thanks: 1
Thanked 74 Times in 70 Posts
Rep Power: 4
bobperry will become famous soon enough
Re: Modern Hull forms and Motion Comfort

One:
WPA is not a two dimenional way to look at loading. It would be if WPA was the only component but you multiply the WPA by 64 and divide that by 12 to get lbs, per inch so it most definetely is not "two dimenional" as used.

I have no interest in getting into a pissing match here. My only interest is seeing discussions of yacht design elements be kept accurate. I have just returend form NC where my 60' ketch is being built and having read the posts that were posted while I was gone I'm not sure I want to stay on with this thread. People see what they want to see and this thread is a good example of that. I have no inclination to try to change that. I'm just a yacht designer, not a shrink.

I'll think about Wolf's project and correspond privately with Jeff.
__________________
Please visit my blog. It's fun to read.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Bob's Blog ....

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Please also visit my new web site
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
  #190  
Old 04-19-2013
Resolute_ZS's Avatar
Kayaker/Dreamer
 
Join Date: Oct 2012
Posts: 122
Thanks: 2
Thanked 1 Time in 1 Post
Rep Power: 2
Resolute_ZS is on a distinguished road
Re: Modern Hull forms and Motion Comfort

Sorry to hear you're backing out of this thread, Bob, but I can understand. If you're still reading - do you have a link to your ketch? I'd love to see what you're building. (I've been lurking in the Sliver thread on SA too...)
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Seakindly Boats vs.the rest rmf1643 Boat Review and Purchase Forum 14 04-10-2013 03:26 PM
What can you tell from the numbers? brazilnut Boat Review and Purchase Forum 10 07-01-2009 04:09 PM


All times are GMT -4. The time now is 03:10 AM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.