Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 03-05-2016, 04:39   #1
Registered User

Join Date: May 2016
Boat: slowly designing a worldcruiser for early retirement
Posts: 22
Why did wooden ships never get much beyond 300 feet...

Pretty self explanatory, and have seen random discussions over the internet in the past - am aware of issues like heave and such. But I guess I don't fully understand the physics involved...

If it's 100% wood I could understand the limitations being flex and movement, but I assumed that if steel or metal framing (or even carbon fiber) were used for the global strength issues, i'm not sure why the hull would behave that much differently than any other hull. (being mostly local strength issues I would assume/don't understand why it would inherently leak if it's main job is to keep the water out and the frame absorbed the loads) Since we've had metal for awhile, is there an unsolvable engineering problem at large sizes they just didn't solve, or is it just as unfeasible now?


If i'm in the wrong form please move me to where it belongs, thanks.
__________________

__________________
black_sails is offline   Reply With Quote
Old 03-05-2016, 04:55   #2
Registered User

Join Date: Oct 2015
Location: Germany
Boat: 2ft wide dreaming chair
Posts: 311
Re: Why did wooden ships never get much beyond 300 feet...

fwiw, the chinese build >400ft ships in the 15th century out of wood.
google "Zheng He"
__________________

__________________
Simonsays is offline   Reply With Quote
Old 03-05-2016, 05:01   #3
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: Why did wooden ships never get much beyond 300 feet...

Elated you're already on the move here!
HAHA! Simon beat me to it while I was copying and pasting...

If recorded accounts are taken as factual, Zheng He's treasure ships were mammoth in size with nine masts and four decks, capable of accommodating more than 500 passengers, as well as a massive amount of cargo. Some of the ships were said to have been 137 meters (450 feet) long and 55 meters (180 feet) wide, which was at least twice as long as the largest European ships of that time. Some sources claim the ships were even longer — 180 meters (600 feet).

Modern scholars argue that Zheng He's ships couldn’t have been that long because wooden ships of such extreme sizes would have pushed the limits of what was possible in wooden ship construction making them unwieldy. There are evidences in later historical periods when ships longer than 100 meters were built, such as HMS Orlando and the schooner Wyoming, and they suffered structural problems. In heavy seas, the ships flexed causing the long planks to twist and buckle. The first ships to attain 126 meters length were 19th century steamers with iron hulls.
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 03-05-2016, 05:20   #4
Registered User
 
captjcook's Avatar

Join Date: Jul 2008
Location: Fort Lauderdale Florida
Boat: Northstar 1500, 35'
Posts: 318
Re: Why did wooden ships never get much beyond 300 feet...

Saw a pbs documentary a couple days ago on this...claimed as many as 60 masts and a thousand crew!


Sent from my iPad using Cruisers Sailing Forum
__________________
captjcook is offline   Reply With Quote
Old 03-05-2016, 05:39   #5
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: Why did wooden ships never get much beyond 300 feet...

Quote:
Originally Posted by captjcook View Post
Saw a pbs documentary a couple days ago on this...claimed as many as 60 masts and a thousand crew!

Sent from my iPad using Cruisers Sailing Forum
Don't you have anything better to do???


----

No kidding?
Was it on this Zeng He feller, or something else?
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 03-05-2016, 05:43   #6
Registered User
 
captjcook's Avatar

Join Date: Jul 2008
Location: Fort Lauderdale Florida
Boat: Northstar 1500, 35'
Posts: 318
Re: Why did wooden ships never get much beyond 300 feet...

Think I have been covering the bases...Yes, Zenge He...and his voyages...seems when he died, the Chinese quit exploring also...


Sent from my iPad using Cruisers Sailing Forum
__________________
captjcook is offline   Reply With Quote
Old 03-05-2016, 05:45   #7
Registered User

Join Date: Oct 2015
Location: Germany
Boat: 2ft wide dreaming chair
Posts: 311
Re: Why did wooden ships never get much beyond 300 feet...

i have a concept pic lying around somewhere with a row of wingsails on each side of the ship.
totaly feasible, the Chinese actualy could have done it that way.
keeps the CoE low and the rig fractions managable.
30 masts per side on a 400ft djunk, why not?
documented crew on the flagship was 500.
__________________
Simonsays is offline   Reply With Quote
Old 03-05-2016, 05:46   #8
Registered User
 
El Pinguino's Avatar

Join Date: Aug 2013
Location: Punta Arenas ahorra
Boat: 39' Westerly Sealord
Posts: 3,952
Re: Why did wooden ships never get much beyond 300 feet...

I was going to suggest that they simply ran out of trees... but this suggests otherwise..'enough wood has been used in these ships to build a bridge 26' wide and 1" thick between America and France, '

The standard wooden cargo steamships of World War I

Then they ran out of trees...

Interesting that they were still under 300 feet when steel shipbuilding had moved on to far bigger things...
El Pinguino is offline   Reply With Quote
Old 03-05-2016, 05:50   #9
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: Why did wooden ships never get much beyond 300 feet...

Quote:
Originally Posted by captjcook View Post
Think I have been covering the bases...Yes, Zenge He...and his voyages...seems when he died, the Chinese quit exploring also...
Sent from my iPad using Cruisers Sailing Forum
Saw/Read/Know that too... giant "lull' in the seafaring history from them to the Portugese...

Well dang if they don't have the whole ting on youtube... Twice!
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 03-05-2016, 08:23   #10
Registered User

Join Date: Mar 2015
Location: channel islands
Boat: lancer 36
Posts: 268
Re: Why did wooden ships never get much beyond 300 feet...

noah built himself a pretty big boat. so they say anyway. something like forty cubits, whatever a cubit is.
__________________
jrbogie is offline   Reply With Quote
Old 03-05-2016, 08:31   #11
Registered User

Join Date: Nov 2013
Location: Homeport: Oswego, NY
Boat: 1993 Sabre 362 #113
Posts: 351
Re: Why did wooden ships never get much beyond 300 feet...

Quote:
Originally Posted by black_sails View Post
Pretty self explanatory, and have seen random discussions over the internet in the past - am aware of issues like heave and such. But I guess I don't fully understand the physics involved...

If it's 100% wood I could understand the limitations being flex and movement, but I assumed that if steel or metal framing (or even carbon fiber) were used for the global strength issues, i'm not sure why the hull would behave that much differently than any other hull. (being mostly local strength issues I would assume/don't understand why it would inherently leak if it's main job is to keep the water out and the frame absorbed the loads) Since we've had metal for awhile, is there an unsolvable engineering problem at large sizes they just didn't solve, or is it just as unfeasible now?


If i'm in the wrong form please move me to where it belongs, thanks.
An issue with large wooden boats is hogging. There is less buoyancy in the stems, this causes the keel to bow, i.e., the there is a curve in the keel with the ends being lower than the middle.

I assume it could be corrected by increasing the buoyancy in the ends and/or bigger stiffer keel timbers, but those solutions affect performance and add weight and reduce volume.

Then there is cost effectiveness, a big wooden ship requires more maintenance that a similar one of composites or metal.
__________________
Dave Lochner is offline   Reply With Quote
Old 03-05-2016, 08:33   #12
Registered User

Join Date: Sep 2012
Posts: 4,945
Re: Why did wooden ships never get much beyond 300 feet...

Yes Noah's boat must have been very very big.
__________________
robert sailor is offline   Reply With Quote
Old 03-05-2016, 08:42   #13
Registered User

Join Date: Oct 2012
Location: Seattle
Boat: Tayana Mariner 36
Posts: 88
Re: Why did wooden ships never get much beyond 300 feet...

To answer the OP, it's mostly economics, not an engineering limitation.
Especially true for vessels enaged in trade, they are truly designed to meet certain service requirements, while making a profit for the investors.
Big isn't always better in maritime trade, depending on the service, and historically (and even in most parts of the world today) ships were also limited in size by shipyard physical constraints, shore-side infrastructure, size / capacity of ports of call, and ship husbandry capabilities. The economics in the age of wooden ships likely led to the conclusion that 4 300' ships made more money than 1 600' ship, for example.
Today, it's simply that a large steel ship is cheaper than a large wood ship, and we always are talking life-cycle costs over the intended service life.
__________________
bauer965 is offline   Reply With Quote
Old 03-05-2016, 09:30   #14
Registered User

Join Date: Oct 2014
Location: Arnold MD
Boat: Cape Dory 300 MS 30'
Posts: 22
Re: Why did wooden ships never get much beyond 300 feet...

I am not a naval architect but I encountered one in Vancouver who had built a "Chinese Junk" design about 35' long. He told me that there were no high stress points in such a hull. It could be made of ordinary lumber and was easily repaired anywhere. The masts are short and unstayed, supported by strong "partners" both at deck level and at the mast step. He saw no reason why these techniques were not scalable to much larger ships. He also said the typical junk sails were the easiest rig he had ever used, readily reefed when necessary. Although nor very close-winded by modern standards, they could easily outsail a conventional square-rigger to windward.

Zheng He's exploits are the subject of "1421" a book by Menzies which not only explains the background of Chinese navigation but also their method of determining longitude (moon transit) and latitude (which they knew had a constant error, enabling them to apply a correction). He also details the banning of foreign travel by the next Ming emperor who tried to burn all of China's ships. Captain Fred
__________________
Captain Fred is offline   Reply With Quote
Old 03-05-2016, 09:55   #15
Registered User

Join Date: Jun 2015
Location: Nova Scotia
Boat: S&S Loki Yawl 38'
Posts: 89
Re: Why did wooden ships never get much beyond 300 feet...

Quote:
Originally Posted by black_sails View Post
Pretty self explanatory, and have seen random discussions over the internet in the past - am aware of issues like heave and such. But I guess I don't fully understand the physics involved...

If it's 100% wood I could understand the limitations being flex and movement, but I assumed that if steel or metal framing (or even carbon fiber) were used for the global strength issues, i'm not sure why the hull would behave that much differently than any other hull. (being mostly local strength issues I would assume/don't understand why it would inherently leak if it's main job is to keep the water out and the frame absorbed the loads) Since we've had metal for awhile, is there an unsolvable engineering problem at large sizes they just didn't solve, or is it just as unfeasible now?


If i'm in the wrong form please move me to where it belongs, thanks.
Even with the modern materials we have, wood is still a wonderful material for structures. But to answer your question, the size limitation that you speak of is mainly due to the mechanically fastened connections in the wood. You lose strength and stiffness at every joint and it's hard to find 300' trees. (grin) With modern adhesives and proper techniques this is no longer a problem and I don't think that there is a size limit for wooden structures. There are good reasons that despite the fact that balsa can rot that it is the preferred core material. I was chatting once with an excited sailplane pilot that had just gotten delivery of a very expensive German built composite plane and he was saying how glad he was to have an all fiberglass and carbon ship. I pointed to the brownish colour forming the shear web in the main spar and yep, it's wood.
The same amount of wood (on a weight basis) is actually far stiffer than the same weight in fibreglass. James
__________________

__________________
Lokiyawl 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




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 03:08.


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.