Cruisers & Sailing Forums (https://www.cruisersforum.com/forums/)
-   Monohull Sailboats (https://www.cruisersforum.com/forums/f47/)
-   -   Why did wooden ships never get much beyond 300 feet... (https://www.cruisersforum.com/forums/f47/why-did-wooden-ships-never-get-much-beyond-300-feet-165533.html)

black_sails 03-05-2016 03:39

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.

Simonsays 03-05-2016 03:55

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"

HappyMdRSailor 03-05-2016 04:01

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... :thumb:

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.

captjcook 03-05-2016 04:20

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

HappyMdRSailor 03-05-2016 04:39

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by captjcook (Post 2111826)
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???
:whistling:

----

No kidding?
Was it on this Zeng He feller, or something else?

captjcook 03-05-2016 04:43

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

Simonsays 03-05-2016 04:45

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.

El Pinguino 03-05-2016 04:46

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...

HappyMdRSailor 03-05-2016 04:50

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by captjcook (Post 2111845)
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!
https://www.youtube.com/watch?v=Ckdn18SAldg

jrbogie 03-05-2016 07:23

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.

Dave Lochner 03-05-2016 07:31

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by black_sails (Post 2111810)
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.

robert sailor 03-05-2016 07:33

Re: Why did wooden ships never get much beyond 300 feet...
 
Yes Noah's boat must have been very very big.

bauer965 03-05-2016 07:42

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.

Captain Fred 03-05-2016 08:30

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

Lokiyawl 03-05-2016 08:55

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by black_sails (Post 2111810)
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

MarkJ 03-05-2016 09:10

Re: Why did wooden ships never get much beyond 300 feet...
 
Because its too long to walk with a peg leg and parrot on your shoulder.

Cadence 03-05-2016 09:21

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by bauer965 (Post 2111979)
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.

That and one going down would not be as catastrophic. Not the owners probably cared about the crew just the pocketbook.

reed1v 03-05-2016 09:25

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by Dave Lochner (Post 2111963)
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.

Hogging occurs as the ship ages. ends sag downward due to less support from the water vs the middle section. Actually occurs with steel ships as well, just not as pronounced. However, most commercial ships are usually designed to last about 20 years in service so hogging is not a relevant issue.

There is no theoretic limit as to how big you could build a wooden ship. Just by the time they were replaced by steel, 300 or so feet was about the max most shipyards could handle. Once you get to overhead cranes, dry docks, and modular construction, virtually any size economically feasible can be built.

Shrew 03-05-2016 09:47

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by jrbogie (Post 2111956)
noah built himself a pretty big boat. so they say anyway. something like forty cubits, whatever a cubit is.

Traditionally the distance from the tip of the middle finger to the elbow.

1 cubit = 1.47637795276 ft
0.4572 meter

Dimensions of the vessel: 300 cubits in length,
50 cubits in width
30 cubits in height

Stumble 03-05-2016 10:09

Re: Why did wooden ships never get much beyond 300 feet...
 
As mentioned hogging, and it's corrilary sagging start to become insurmountable problems when the length of wooden ships excedes about 300'. Simply put the Youngs Modulus simply isn't high enough for the material to resist the flex generated.

It isn't just wave action that is an issue here, turning a 300' long ship exerts tremendous torque loads on the hull, and wood simply isn't stiff enough to resist them. The boat will start to flex and pop seams pretty quickly.

All materials have this issue of course, but the stiffness of other common boat build materials is just much higher. It's the same reason steel ships have a maximum theoretical size of a couple of thousand feet. I am not sure exactly but what I remember is somewhere in the 2,500' range (about double the longest ship ever built) is the upper limit for steel.


Not that good engineering today couldn't probably build a better 300' wooden ship than in the age of sail, but the material limitations still apply.

TurninTurtle 03-05-2016 10:29

Re: Why did wooden ships never get much beyond 300 feet...
 
The size of a cubit changed... because the size of people changed. 5 ft used to be tall.

kentobin 03-05-2016 14:13

Re: Why did wooden ships never get much beyond 300 feet...
 
I've talked to a wooden boat surveyor and it's not just the fact that the wood flexes but if there are continual forces it starts to take on a permanent bend in the direction of the force. He showed me reinforcements to a wooden hull that attempt to try and counter the pull of the standing rigging. It helps but it doesn't stop it and this was just in a 24 foot boat.

Even wooden power boats have problems with torque and flexing and taking on a new shape but I don't remember any specifics of their issues.

Oceanride007 03-05-2016 16:22

Re: Why did wooden ships never get much beyond 300 feet...
 
As then as now, the worse case a vessel can find itself in, is when the pitch of the wave is the same as the length of the vessel. When the wave is midship, it hogs, when the wave is at ships end, it sags.
Modern ships over a certain size but fairly recent, had to change to longitudinal construction (Longitudinal stringers), notch tough steels, designs that avoided stress raisers, high fatigue life. What is still difficult is achieving these requirements, while still avoiding corrosion and the wish to maximise return to the investor. Would think 25 years would be a good life.
If you could build a wooden vessel of sufficient beam strength, and restore strength across a join, and if you could convince a investor/dreamer, yes longer ships would have occurred.

HappyMdRSailor 04-05-2016 04:37

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by MarkJ (Post 2112059)
Because its too long to walk with a peg leg and parrot on your shoulder.


HAAAAAAAAAAAAAAAAAAAA!!!!! :thumb:

black_sails 04-05-2016 05:06

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by Stumble (Post 2112111)
As mentioned hogging, and it's corrilary sagging start to become insurmountable problems when the length of wooden ships excedes about 300'. Simply put the Youngs Modulus simply isn't high enough for the material to resist the flex generated.

It isn't just wave action that is an issue here, turning a 300' long ship exerts tremendous torque loads on the hull, and wood simply isn't stiff enough to resist them.


I can understand that far, but would it be the same if there were a steel frame and wood were only used as the outer hull material? I would have assumed it's a global vs local strength issue.

I guess part of my curiosity is that I assume if a steel frame wooden 'envelope' hull would have worked, why wasn't that seen...

Jim Cate 04-05-2016 14:32

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

I guess part of my curiosity is that I assume if a steel frame wooden 'envelope' hull would have worked, why wasn't that seen...
Quite possibly because the cost would have been higher than simply plating in steel! The additional strength afforded by said plating would likely mean that t he framing would be less expensive to build... a win-win situation.

Jim

El Pinguino 04-05-2016 14:37

Re: Why did wooden ships never get much beyond 300 feet...
 
They did build quite a few composite ships with steel or iron frames and timber planking and a few survive to this day. Cutty Sark was one.
Benefits were that they could copper clad a timber hull but not a steel one and fouling was a major issue on early steel ships... as was electrolysis .

reed1v 05-05-2016 05:08

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by El Pinguino (Post 2113019)
They did build quite a few composite ships with steel or iron frames and timber planking and a few survive to this day. Cutty Sark was one.
Benefits were that they could copper clad a timber hull but not a steel one and fouling was a major issue on early steel ships... as was electrolysis .

Quite true plus related to electrolysis was the electrical field set up by a steel ship. Created havoc with compasses until degaussing tools became available. The field created by moving thousands of tons of steel through salt water is quite significant.

Cherp 05-05-2016 06:35

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by Shrew (Post 2112095)
Traditionally the distance from the tip of the middle finger to the elbow.

1 cubit = 1.47637795276 ft
0.4572 meter

Dimensions of the vessel: 300 cubits in length,
50 cubits in width
30 cubits in height

No, a cubit in the ancient world was (as the name implies) a cube, measuring four fig-fruit lengths a side. That's a very small boat, but you must recognise that Noah and the animals were not evolved to their current size. Noah himself would have been only two feet tall, in today's measure and a few cubits in girth - small but stocky. The flood itself was probably only a couple of hundred gallons. As Albert Einstein said, it's all relative.

Saleen411 05-05-2016 07:28

Re: Why did wooden ships never get much beyond 300 feet...
 
https://en.wikipedia.org/wiki/Nemi_ships

HUGE wooden ships.....more like barges...built over 2000 years ago.

The largest of the 2....240 feet long and 79 feet wide.

boatman61 05-05-2016 07:52

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by Cherp (Post 2113396)
No, a cubit in the ancient world was (as the name implies) a cube, measuring four fig-fruit lengths a side. That's a very small boat, but you must recognise that Noah and the animals were not evolved to their current size. Noah himself would have been only two feet tall, in today's measure and a few cubits in girth - small but stocky. The flood itself was probably only a couple of hundred gallons. As Albert Einstein said, it's all relative.

In reality he just saved his family and livestock.. the rest is Chinese Whispers..:biggrin:
1 Cubit = 45.72 centimetres.

Jdege 05-05-2016 08:20

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by TurninTurtle (Post 2112125)
The size of a cubit changed... because the size of people changed. 5 ft used to be tall.

Historically, height has increased and decreased, based on the quality of the diet.

Longevity & health in ancient Paleolithic vs. Neolithic peoples

reed1v 05-05-2016 13:08

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by boatman61 (Post 2113462)
In reality he just saved his family and livestock.. the rest is Chinese Whispers..:biggrin:
1 Cubit = 45.72 centimetres.

Evidently everyone has forgotten their grammar school latin classes. Cubit has nothing to do with cubes. Means Elbow. Not even pronounced as cub-it, but as coo bit. So much for the decline of western knowledge. Now go back and brush up on your latin and greek lessons.

El Pinguino 05-05-2016 13:36

Re: Why did wooden ships never get much beyond 300 feet...
 
While wooden sailing ships may not have exceeded 300 feet steel ships didn't get a whole lot bigger for many years... pre WW2 the only exception being a few oil tankers and of course passenger liners ... and the Great Eastern. Standard designs in WW2 were about 400 feet and even into the 50's British cargo liners only grew to about 500 feet.

reed1v 05-05-2016 13:41

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by El Pinguino (Post 2113667)
While wooden sailing ships may not have exceeded 300 feet steel ships didn't get a whole lot bigger for many years... pre WW2 the only exception being a few oil tankers and of course passenger liners ... and the Great Eastern. Standard designs in WW2 were about 400 feet and even into the 50's British cargo liners only grew to about 500 feet.

Part of the reason was the need to build ships that would fit into existing dockage and channel drafts. Its way more expensive to rebuild dockage than to build a ship. You could build a 2000' ship but no one is set up to handle it.

Snowpetrel 05-05-2016 14:25

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by reed1v (Post 2113350)
Quite true plus related to electrolysis was the electrical field set up by a steel ship. Created havoc with compasses until degaussing tools became available. The field created by moving thousands of tons of steel through salt water is quite significant.

Flinders bars and kelvins balls plus permenant magnets where understood and used long before the need to degauss ships to reduce the magnetically triggered mine danger in WW2.

reed1v 05-05-2016 14:41

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by Snowpetrel (Post 2113699)
Flinders bars and kelvins balls plus permenant magnets where understood and used long before the need to degauss ships to reduce the magnetically triggered mine danger in WW2.

Those old methods worked well on wooden ships but not so well on steel ships, especially when surrounded with all sorts of electrical systems. One problem that confounded the Navy was how the magnetic fields kept changing due to course heading, stowage of supplies, and even the act of degaussing affected the compasses. Nowadays other systems become important to shield from the changing magnetic field--satcom, guidance systems, etc.

So yes, Flinders bars worked, but not for protecting other systems from powerful magnetic fields. Now lets see, where did we store the fifty tons of gun powder for our 16 inch guns?

boatman61 05-05-2016 15:03

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by reed1v (Post 2113647)
Evidently everyone has forgotten their grammar school latin classes. Cubit has nothing to do with cubes. Means Elbow. Not even pronounced as cub-it, but as coo bit. So much for the decline of western knowledge. Now go back and brush up on your latin and greek lessons.

Studied English, Hindi and Urdu not Latin.. as for the measurement I quoted.. that came from Western scholars who alledgedly know it all..:whistling:

black_sails 05-05-2016 15:09

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by Jim Cate (Post 2113015)
Quite possibly because the cost would have been higher than simply plating in steel! The additional strength afforded by said plating would likely mean that t he framing would be less expensive to build... a win-win situation.

Jim

Hmm... that's a good point! Though it's more trying to understand the engineering side than the economics side.

Snowpetrel 05-05-2016 15:30

Re: Why did wooden ships never get much beyond 300 feet...
 
Quote:

Originally Posted by reed1v (Post 2113712)
Those old methods worked well on wooden ships but not so well on steel ships, especially when surrounded with all sorts of electrical systems. One problem that confounded the Navy was how the magnetic fields kept changing due to course heading, stowage of supplies, and even the act of degaussing affected the compasses. Nowadays other systems become important to shield from the changing magnetic field--satcom, guidance systems, etc.

So yes, Flinders bars worked, but not for protecting other systems from powerful magnetic fields. Now lets see, where did we store the fifty tons of gun powder for our 16 inch guns?

Ha, nobody told any of the large steel comercial ships still steaming regularly around the world that they are using outdated technology that doesnt work!


All times are GMT -7. The time now is 17:34.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2021, vBulletin Solutions, Inc.


ShowCase vBulletin Plugins by Drive Thru Online, Inc.