Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 29-01-2009, 12:50   #181
Registered User

Join Date: Oct 2006
Location: The boat lives at Fidalgo Island, PNW
Boat: 36' custom steel
Posts: 992
Three posters, each contending that Brewer's motion comfort number amounts to oversimplification. That says something.

I think Paul's observation about the Alberg pitching in a seaway is right on the mark. The MC number makes no allowance for that. Great example.

Some numbers are more useful than others. For example, SA/D and B/D ratios are very useful numbers, IMO. D/L less so. Bottom of pile are MC and CSR. They are just way too simplistic for what they are trying to capture.

You have to sail the boat to find out how she feels when sailing, or talk to somebody who has. There is no substitute for on-the-water experience.

Which is not to say that there can't be real differences in motion comfort. There can be differences, in some cases big differences, in many only cases slight differences. Whatever. The subject of motion comfort is too complex, AND TOO SUBJECTIVE, to fully quantify.

Expanding the subject to include the motion of multihulls only underscores how subjective the subject really is. (Was that an echo in here?)

I think Stephen has done the thread a favor by posing the question about the utility of Brewer's number.
__________________

__________________
John, sailing a custom 36' double-headed steel sloop--a 2001 derivation of a 1976 Ted Brewer design.
Hiracer is offline   Reply With Quote
Old 29-01-2009, 12:53   #182
Registered User

Join Date: Oct 2006
Location: The boat lives at Fidalgo Island, PNW
Boat: 36' custom steel
Posts: 992
Quote:
Originally Posted by Jim Cate View Post

I reckon that Mr. Brewer's comments here are correct, but he doesn't point out that the slow vertical acceleration also means that the boat is going to have a greater chance of getting green water on deck. So, the price of a more comfortable ride may be a wet bum! Each sailor must choose which is more important to him.
Again, I don't think it's that simple. Freeboard, shape of the hull, and boat speed all play a big part in how wet the boat might be relative to other boats.

I have a friend who just had his 51' Beneteau delivered to him in Austrialia by one of his best friends. The comment by both owner and delivery captain is, "Wow, this is one wet boat." Yet it's a light boat.
__________________

__________________
John, sailing a custom 36' double-headed steel sloop--a 2001 derivation of a 1976 Ted Brewer design.
Hiracer is offline   Reply With Quote
Old 29-01-2009, 13:01   #183
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,577
Images: 240
BOB:
Stephen Phillips asked you how we amateurs might best use the noted ratios, not how a professional might view them as insufficient.
Given that most of we cruisers have not spent our professional careers acquiring your abilities to understand and use “the fragmented formulae that [you] have worked with for the past 41 years", what are we mere amateurs to use to get “little glimpses into the character of the boat”?

Perhaps, as you've indicated (?) they can "red flag" features that require further study.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 29-01-2009, 13:03   #184
Registered User

Join Date: Oct 2006
Location: The boat lives at Fidalgo Island, PNW
Boat: 36' custom steel
Posts: 992
Quote:
Originally Posted by GordMay View Post
BOB:
Stephen Phillips asked you how we amateurs might best use the noted ratios, not how a professional might view them as insufficient.
Given that most of we cruisers have not spent our professional careers acquiring your abilities to understand and use “the fragmented formulae that [you] have worked with for the past 41 years", what are we mere amateurs to use to get “little glimpses into the character of the boat”?
I really think the answer is, the grapevine. Talk to people. Collect opinions from good sources and average out.

The Internet can helps, lots.
__________________
John, sailing a custom 36' double-headed steel sloop--a 2001 derivation of a 1976 Ted Brewer design.
Hiracer is offline   Reply With Quote
Old 29-01-2009, 15:08   #185
cruiser

Join Date: Nov 2008
Posts: 506
Gord:
Here is how I got started working with the ratios when I was a kid. I would gather together all the specs I could on various boats. The I would start calculating all the ratios and making comparative tables of the various ratios. ( with a slide rule) I did a lot of cross referencing. I was a kid. It was my hobby. I had the time. As time went on I accumulated a huge file of data on differnt boats and over the years the numers slowly began to make some sense. I kept my files in an old, batterred wine box. It was chock a block full by 1971 then my girlfriend's cat peed in it and I had to throw the entire messout. But by then I had started to develope a feel for what the numbers meant.

And let me say that it doies not matter how you personally breakdown the categories, i.e. what is "light" and what is "heavy". All that matters is that you get a relative feel for the numbers that means something to you. One man's light boat is another man's heavy boat. I have my own breakdown but if you don't like it find your own.

I think all these numbers are very useful when you have worked with them for a long time. On their own they tell you little. To many of the uninitiated the nujmbers appear to be sacred but it's not that simple. If it were boats would tend to all look the same. To some degree you can see tjis now in the racing classes as science grabs a tighter and tighter hold on the design issues. But with cruising boats there is always that element of subjectivity to keep things interesting and fluid.

I was sitting at the old Narita airport in Japan years ago, As I looked down the long line of parked planes I noticed how many diffeent rake angles they had on their tail's leading edges. I thought to myself, "Some one is guessing."


Red flags:
While I don't worship the ratios I pay attention if I get one that is out of the norm. I stop, backtrack and try to define why I am getting one weird number. If everything looks fine except for that one number I may be inclined to ignore it and forge ahead. I may not. Often times a weird number is a function of a calculating error.

I know this must have been mentioned a hundred times but if you are going to work with these ratios you must have faith that the parent numbers you are using are correct. They are often not and can be scewed by "the marketing department".
__________________
bob perry is offline   Reply With Quote
Old 29-01-2009, 17:09   #186
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,347
great post Bob

"the whole is equal to the sum of the parts"
__________________
Cheechako is offline   Reply With Quote
Old 29-01-2009, 18:21   #187
Registered User

Join Date: Jan 2009
Location: New England
Posts: 3
Regardless of the adequacy of Carl's Sailboat Calculator and the Sail Boat Data Base on http://www.johnsboatstuff.com/default.htm , these numbers might be the only objective reference that we have. Ted Brewer, to his credit, recognized the problem and the utility of defining a standard with which to compare relative comfort.

Every time I have reviewed everyone's comments, I have had a better understanding of their wisdom. To sort of paraphrase Bob, by the time you understand the numbers, you don't need them. Well, that does not resolve the new sailor's conundrum of trying to narrow a universe of used boats to just a few boats. Do we just simply ask what boat should I buy? Owners invariably say that they like their boat, but know little or nothing about similar boats. We cannot sail them all. Do we buy a dog just because it sails better than the pigs that we have previously sailed?

Is my own search for a used boat similar to anyone's experience? I am looking for a very comfortable "cruiser", a rock with a fair amount of speed, and less than 38' LOA. Subjective criteria such as quality of construction, cabin layout, and beauty are outside the numbers. I have studied all the numbers in Carl's Calculator to objectively narrow the search for boats that meet my various subjective criteria. I have a very short list of boats, and I am using the Tashiba 31 and 36 as my standards. Paul's comments regarding the J/37 now make me wonder if my initial selection process is all wrong?
__________________
Stephen Phillips is offline   Reply With Quote
Old 30-01-2009, 09:28   #188
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,569
Stephen,
Your search approach is not that different from most others. The problem is that without significant experience doing the type of sailing that you will end up doing, you aren't sure what is really important to you. A clear Catch-22. I'd suggest you think through what type of sailing will you really do. Will it be coastal, medium offshore, or ocean passages. How long do you plan to be out? Single-handed or crewed -- I believe you've already said solo. And probably most important how much you have to acquire the boat and fix it up for this type of cruising. The dollar amounts will drive a lot of the decision process. If you are planing on solo then I'd go for an easily sailed boat. One with excellent sail handling gear, one that can be sailed in light airs without a ton of work -- unless you plan to motor a lot, which is fine as long if you go for tankage. Then check on the construction rep of each boat. Any of the production boats built over the last 30-years are easily found on somebodies website -- knowing before you buy a boat that the iron tanks are going to fail and are hell to replace is a lot better than finding out latter.

You might think about taking Bob P up on his very low cost boat finding consultation service. For a fixed fee he will consult with you on your choices till you find the boat for you. The guy has reviewed a ton of boats, seems to love all types of them and understands what it takes to sail them offshore. Plus he's an very interesting guy to BS with.

Paul L
__________________
Paul L is offline   Reply With Quote
Old 30-01-2009, 10:12   #189
cruiser

Join Date: Nov 2008
Posts: 506
Paul is correct. I am an interesting guy to BS with. Darn good looking too.

I think what I offer is a lifetime of experiences in a wide variety of boats from International 14 dinghies to Cape Cod Catboats. I like to think I have an appreciation for the variopus types. I love the J35. I used that boat as a performance yardstick for years. I am an ex-JBoat owner.

I'd launch into a long description of my consultation service here but I'd just get spanked, again. Visit my newly updated web site to read about it. You can also see Pumpkin there, our new cat we found on the side of the road.
__________________
bob perry is offline   Reply With Quote
Old 30-01-2009, 12:11   #190
Registered User
 
Amgine's Avatar

Join Date: Dec 2004
Location: Vancouver BC
Posts: 1,384
Images: 1
Yeesh!

For those unaware, Bob's site is Robert H Perry Yachts Designers Inc. Home Page. And Pumpkin is not a catamaran nor a catboat. ::grumbles about 'too pc to put a link in his sig'::
__________________
Amgine
Blog

On the internet, nobody knows you're a dog anchored in a coral atoll.
Amgine is offline   Reply With Quote
Old 30-01-2009, 12:41   #191
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,577
Images: 240
Quote:
Originally Posted by bob perry View Post
Paul is correct. I am an interesting guy to BS with. Darn good looking too...
... I'd launch into a long description of my consultation service here but I'd just get spanked, again. Visit my newly updated web site to read about it. You can also see Pumpkin there, our new cat we found on the side of the road.
Interesting & beautiful? Too bad about your gender.
Notwithstanding, please remind us where (specifically - URL) we can find your site.
As oddly pleasurable as that may seem, I promise no spanking will come forth.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 30-01-2009, 12:43   #192
Moderator Emeritus
 
GordMay's Avatar

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 31,577
Images: 240
I should read more carefully.
Thanks Amgine, for providing a link to Bob's website.
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"



GordMay is offline   Reply With Quote
Old 30-01-2009, 13:42   #193
cruiser

Join Date: Nov 2008
Posts: 506
My website is perryboat.com

Gord is going to talk to the other administrators and fix things so I be in full compliance with the forum's rules.
"I want to be in full compliance officer."

This will give me the freedom as a "commercial vendor" to vend my wares here, namely my consultation service. But I still want to be able to just chat. Like the rest of you I like to talk about boats.
__________________
bob perry is offline   Reply With Quote
Old 30-01-2009, 13:54   #194
CF Adviser
Moderator Emeritus
 
Hud3's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: Virginia
Boat: Island Packet 380, now sold
Posts: 8,929
Images: 49
Bob is now officially a "Commercial Vendor" here on the Forum.

Vendor status is only offered to those members with commercial interestws who have demonstrated a high degree of professionalism and boating industry knowledge, and who are active and positive participants in the forums.

Glad to have you here, Bob!
__________________
Hud
Hud3 is offline   Reply With Quote
Old 30-01-2009, 15:49   #195
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,310
To think this all started because I asked what people preferred, "speed" or "comfort". Been interesting, but got away... :-)
__________________

__________________
sailorboy1 is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
'Pirates' and 'Pirate Attacks' Euro Cruiser Health, Safety & Related Gear 24 20-08-2010 15:06
Sir Peter Blake's "Seamaster," Now "Tara," Still Hard at Work TaoJones Monohull Sailboats 5 15-12-2009 15:40
Garmin 'In-Hull' vs 'Thru-Hull' Transducers La Bras D'or Navigation 24 23-09-2009 08:26



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 14:51.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.