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Modeling the Extreme Clipper Young America 1853


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#21
Capt.Bob

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Ed,

Square frame pattern 2f.  Top timbers (siding 9") marked 1f

Bob


Bob

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Current Build:  Mantua "USS Constitution - 1797"

 

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#22
jo conrad

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Hi Daves,

 

when I saw Ed´s inside-strapping of the 1/72 YA,  I felt a bit confused :the revolutionary idea behind the installing of an iron "net" to the frames of composite clippers has been to strengthen the wooden hull by double-diagonal iron straps against warping and hogging and any other deformation by wind and sea. At least to my limited and more or less intuitive understanding of mechanical forces, this could only be achieved by bolting a net of these straps all around the outside of the hull like a string bag, thus absorbing and counteracting the flexing and compressing forces on the ship´s body by transforming them into tractive forces induced into the straps at the outside. The strapping installed at the inside of the frames would mainly pull and sheer at the fastening bolts and thus loosen them after a while, but in my opinion it can not keep the hull straight. My example of a string-bag keeping your shoppings together is maybe not so bad a picture.

 

As I wasn´t 100% sure about that, and because Ed is of course by far deeper in this business than me, I didn´t want to be precocious and kept this thought to myself. But to me it still seems to be the logical way of reinforcing a wooden - and of course - an iron hull.

Greetings to all.

Germanus


Edited by jo conrad, 11 January 2016 - 12:02 PM.

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#23
EdT

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daves,

 

Thank you for your comments and for the opportunity for me to expand on the decision I made for the iron strapping.

 

While it is true that the method of iron strapping used on Young America, built in 1852-53, is uncertain, it is by no means cclear that outside strapping was widely used at the time or that internal strapping was rare.  It is true that outside strapping appears to have become more prevalent after the 1850’s.  Space did not permit a full discussion of the history of iron strapping, nor was in-depth construction history the primary purpose of the book.  I did discuss the decision to use internal strapping in Chapter 8 of the book and quote the relevant passage:

 

“A lattice of diagonal iron bands came into use in the early 19th century to help stiffen wooden hulls against hogging strains.  Young America had such banding.  The bands were normally about 4" wide by ¾" thick, spaced on a grid about four feet apart.  The lattice extended over most of the hull length between the floor heads and the main deck clamps.  The bands were set into scores cut into each frame to provide a flush surface for planking. They were bolted through every frame and where they overlapped.  This configuration was documented for Challenge, a similar clipper launched by Webb two years earlier.  However, it is not known whether the ironwork on either of these ships was installed inside or outside of the frames.  Both methods were in use, with outside installation becoming more common in later years.  Although it offered some technical advantage, outside strapping was much more difficult and time consuming to install.  After reviewing available information and considering the urgencies of the times on construction schedules, I decided to adopt the internal installation for the model.”

 

A more thorough discussion of the topic was included by Bill Crothers in his book The American-built Clipper Ship pp 195-196.  I believe he summarized the issue quite well – and the uncertainty.  As with many of the undocumented details of the model, choices have had to be made – or there would be no model.  After reviewing available information on the subject this appeared to indeed be a toss-up issue.  I was influenced in my decision by the following factors:

 

-          The internal or “Admiralty” system, developed for use by the Royal Navy was prevalent during the first half of the 19th Century.

 

-          Webb was the first American builder to adopt iron strapping on Challenge in 1851.

 

-          Webb used internal iron strapping on Ocean Monarch in 1856 as referenced by Crothers based on Webb’s published Plans of Wooden Vessels.

 

-          American Lloyds’ Registry of American and Foreign Shipping, 1859 includes the following passage under Rules for Inspection and Classification:  “Ships exceeding four times their breadth in length, should be cross(X) iron strapped diagonally on the inside – outside strapping leakage through the seams of outside plank will corrode and destroy the iron.  The bolts through the straps either from out or inside should go through and clinch.”

 

-          Speed of construction was a primary driver in the hectic extreme clipper rage of the early 1850’s – driven by the demands of the California gold rush market.  Outside strapping was much more time consuming to install, especially in the days before pneumatic drills, chisels and hammers.  While not a primary argument for internal installation, it was a factor considered.

 

On balance, while not being clear cut, I believe the decision to use internal strapping on the model was reasonable and should be considered a more likely actual scenario than a one-off rarity.

 

Ed

 

 


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#24
daves

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  I started researching the idea of strapping many years ago when i built a model of the Argo a great lakes wooden bulk freighter. drawn on the plans as a cross hatch i had no idea what it was. After more research i found this strange cross hatch on hundreds of plans. Looking deeper into it i found out this was iron straps on the outside of the frames. A number of shipwrecks confirmed they were indeed straps set into the outer face of frames. The way it was explained to me was this strapping created something like an iron basket that a hull sat in thus preventing hogging and twisting of the hull. 

 

Because there is no research to confirm if the straps were on the inside or outside on the hull of the YA then your right in the gray area Ed it could go either way. If i were to bet on it i would bet they were on the outside only because there are wrecks showing it that way and published in ship construction books. also the wide band at the sheer is a major part of the system which you can see drawn on the plan..

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  • strapping.jpg

Edited by daves, 11 January 2016 - 03:50 PM.

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#25
EdT

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Hello Bob,

 

For some reason your post of 22 December just popped up on the blog so I apologize for the delayed response.  The mislabeling of the toptimbers on pattern sheet 2f is clearly another one of those typos - if I may use that term to describe minor glitches in labeling on the drawings.  A revised pattern sheet is attached.

 

Ed

 

Attached File  2f.pdf   15.8KB   102 downloads


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#26
rtropp

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Ed,

I am starting to schedule my next build... which should be a while yet.  I know you have not started it yet, but can you estimate when you plan to have Volume two of young america published?

 

Richard 


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#27
EdT

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Richard, unfortunately it is difficult to make an accurate prediction on the next volume.  I believe it will be no less than two years considering the amount of modeling needed plus the time to write and produce the book.  The publication date will also be subject to the Seawatch publishing schedule.  I can tell you that both Seawatch and I want to get the book out as soon as we can.

 

Ed


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#28
Capt.Bob

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Hi Ed,

Here are a few items for the revision file.

1. Page 57 First paragraph.  Is: "...and pushed through the hole; See Figure 5-26..."  Should be: "See Figure 5-27"

2. Pattern Af: No siding reference.  Missing 2 holes in Floor (both f & a) 

3. Pattern Aa: 5th Futtocks "110"  Should that be 11 or 10?

4. Pattern 27a: Missing top hole in 5th Futtock

5. Pattern Ea: No parting line in the floor timber

6. Patterns Ea/f, Fa/f, Ga/f, Hf, Jf : No siding or futtock data

 

Bob


Edited by Capt.Bob, 17 February 2016 - 05:41 AM.

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Bob

____________________________________________

Current Build:  Mantua "USS Constitution - 1797"

 

Pending:  Model Shipways "USS Constitution"

 

Completed:  Model Shipways "USF Essex -1799"

                    Model Shipways "New Bedford Whale Boat"

                    Billings "Zwarta Zee" (RC)

                    BlueJacket "Sequin" Tugboat (RC)


#29
rwiederrich

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This is why Elton John hired 50 proof readers for the *Yellow Brick Road* album....and they still left errors.  It's tough keeping all the details in order..with such a complex system.  Still it is a great book.....

 

Rob


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Current build:

Build log: of 1/96 Glory of the Seas:Glory of the Seas

 

Current 

Build log: of 1/128th Great Republic: http://modelshipworl...-clipper-1853/#

 

Current build:

Build log: 1/96  Donald McKay:http://modelshipworl...iederrich-1855/

 

Completed build:  http://modelshipworl...y-sark-plastic/

 


#30
EdT

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Thanks, Bob.  I will issue revisions, of course.  I keep telling myself that in almost 300 drawings, checked only by me, that errors are inevitable, but I would still prefer not to have them.  Your attention to this level of detail is most helpful.

 

Fortunately, most have been in the "typo" category.

 

Thanks,

 

Ed


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#31
Roger Pellett

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The principal mode of structural failure in a long ship hull is hogging or sagging due to longitudinal bending. For wooden ships excessive hull flexing causes planks to move relative to each other squeezing out the caulking. The great multi masted schooners in particular suffered from this and required constant pumping.

An unbraced wooden hull can be likened to a stack of boards supported by two saw horses. If you sit in the middle. The stack flexes with each board moving relative to its neighbor. If you nail the same stack together it is much much stiffer as planks cannot slide relative to each other. The forces causing these planks to slide relative to each other are called shear forces.

In a wooden ship, the hull frames provide little or no longitudinal strength as being perpendicular to the planks they do not resist these shear forces. The iron strapping introduces a diagonal restraint into the hull to resist shear forces that move the hull planks. Strapping is not required on the ship's bottom or deck as these are subject only to tensile or compression forces, not shear.

I recently purchased a University of Michigan reprint of an Outline of Shipbuilding by T. D. Wilson, originally published in 1873. This book is also a free on line download. It reflects naval practice but the navy was still building wooden ships in 1873. The book includes a section on diagonal reinforcement. According to Wilson, standard practice was to attach strapping to the inside of the frames as it made subsequent hull repairs easier, but ships of the Congress and Severn class had strapping for 150 feet of the outside of the hull (the amidships area) as well. The Florida and Tennesee were completely strapped on both the inside and outside. These were both long, fine lined vessels, and a lack of buoyancy in their fine lined ends would have increased hogging stresses.

Roger
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#32
EdT

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Thank you for this post, Roger.  I am not familiar with the reference you cite, but will certainly get a copy.

 

Ed

 

ps.  My search on Outline of Shipbuilding by T. D. Wilson did not yield an immediate result.  Could you provide a link to the download site.  Thanks.


Edited by EdT, 19 February 2016 - 12:59 PM.

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#33
Roger Pellett

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Hi Ed,

The full name of the book is An Outline of Shipbuilding, Theoretical and Practical by Theodore D. Wilson. If you Google the full title the first entry is the scanned image of the book. My browser does not provide an exact web address but the above should work.

The availability of this book is a result of Google's project to scan and post rare books online. It is fortunate for ship modelers that one of the two university libraries picked was the one at the University of Michigan because Michigan has had for the past 130 years a Naval Architecture and Marine Engineering department, hence a good collection of old shipbuilding manuals.

If you decide to order this book, I got the hard bound version published by Michigan. Michigan did a nice job of publishing the book BUT it is missing a couple of pages-the last page contains masting rules for warships boats and three Plates presumably showing the lines of a sloop of war. Neither of these omissions would prevent me from buying this book again. There are also paper backed versions but if printed from the same scan would omit the same material.

Roger
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#34
Capt.Bob

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Ed,

There's a paperback copy on Amazon from $22.16.

Bob


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Bob

____________________________________________

Current Build:  Mantua "USS Constitution - 1797"

 

Pending:  Model Shipways "USS Constitution"

 

Completed:  Model Shipways "USF Essex -1799"

                    Model Shipways "New Bedford Whale Boat"

                    Billings "Zwarta Zee" (RC)

                    BlueJacket "Sequin" Tugboat (RC)


#35
Capt.Bob

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Ed,

Question about pin (iron pin) locations.  Some of the pin locations in the 5th futtocks of the last few forward square frames actually exceed the outer edge of the opposite face,  (starting about P).  I wouldn't imagine a shipwright would place the 1" iron bars that close to an outer edge.  Should they be more closely centered ?  Also, some of the pin holes are located very close to the end of some futtocks. Many are closer than the thickness of the futtock.  Are those really scale locations?

 

While I'm here, Pattern Ra has all the segments marked Rf.

 

Just about finished with all the square frames.  Can't wait to get to something different.

Bob


Edited by Capt.Bob, 26 February 2016 - 06:35 AM.

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Bob

____________________________________________

Current Build:  Mantua "USS Constitution - 1797"

 

Pending:  Model Shipways "USS Constitution"

 

Completed:  Model Shipways "USF Essex -1799"

                    Model Shipways "New Bedford Whale Boat"

                    Billings "Zwarta Zee" (RC)

                    BlueJacket "Sequin" Tugboat (RC)


#36
EdT

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Roger and Bob, thanks for the additional information on the book.  I will pursue it further.  We are indeed indebted to Google for their work in scanning and putting online many historical technical works of interest to model builders.  As I write this I am wading through several on 19th century rigging.  

 

Bob, it is true that on some frames the at both ends of the square framed sections where there is maximum frame bevel.  In fact,you should find that the point where the bolts approach either the inner or outer edges of the frames is the point where the cant frames begin, allowing bolts to be driven "normal" - i.e. at right angles to the face of the frame - while not penetrating the outer or inner edges.  Although bolts in these last square half frames are very close to one edge, due to the bevel, they go through the central section of the piece and usually emerge at the opposite (inner or outer) edge on the mating frame.  

 

If this sounds confusing, it is.  The alternatives are to either start the cant frames much closer to midship or to drive bolts at an angle.  The first would weaken the hull significantly.  The latter choice is less clear.  Some sources indicate that bolts were always - or at least preferred to be - driven normal.  However, I found some pictorial evidence (and posted the picture earlier ) of bolt holes being driven at an angle.  This was taken in the early 20th century and a pneumatic drill was being used.  I kept all the bolts normal because I concluded this was the practice at the time (1850's).  Also, and very important to the model, normal holes were essential in the pin-indexed process I adopted for fabricating frames.

 

Keep in mind that these bolts were mainly used to keep the frames connected for erection.  The real strength that held these together came later when the inboard and outboard planking was secured by either structural bolts and or treenails.  At this point I believe the iron bolts through the frames became superfluous.

 

On the frame patterns the holes were placed very carefully on these beveled sections and I found in building the model that none broke through the edges, but as you say, at the ends of the square framed areas, they get very close.

 

I will add the typo you noted on frame Ra to the list.

 

Ed


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#37
Capt.Bob

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Ed,

I'm getting ready to reside the futtocks on A thru U and ran into a curiosity.  On frame Ua the siding of the lower futtocks is marked 12" instead of 14" and labeled "Lower Futtock" instead of "1st Futtock".  Also, the 3rd and 5th futtocks are marked 10" and 9" respectively as opposes to 12" and 10".  This makes Ua unique.  Are the siding references accurate?

 

Bob


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Bob

____________________________________________

Current Build:  Mantua "USS Constitution - 1797"

 

Pending:  Model Shipways "USS Constitution"

 

Completed:  Model Shipways "USF Essex -1799"

                    Model Shipways "New Bedford Whale Boat"

                    Billings "Zwarta Zee" (RC)

                    BlueJacket "Sequin" Tugboat (RC)


#38
EdT

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Hello Bob,

 

The siding references are correct.  Webb reduced weight at the ends of the hull by increasing frame separation and reducing the size of framing timbers at the ends of the hull.  On the patterns I reduced the sidings from frame U forward and from Frame 19 aft.   The exact locations of these transitions could be argued, but this was the basis I used for the patterns.  The forward reductions could have actually been started a few frames aft, but I eventually settled on U.  You will also note that half and cant frames are similarly reduced in siding.  The changes in frame separation are noted on the shipway plan drawing.

 

Webb was a bit more innovative than most other builders in designing to resist hogging of the hull.  Whereas more typical designs utilized additional wood mass (sister or multi tiered keelsons for example) to provide strength, Webb reduced structural weight at the ends by reducing timber sizes.  It is said that by this method about 25 tons could be removed, thus reducing the stress that caused deflection in these areas of decreased buoyancy caused narrowness of the clipper hulls.  Not that Webb skimped on timber as with the huge keelson and heavy ceiling members - also the iron strapping.  He originated the use of iron strapping on American ships with Challenge in 1851.  I  believe this was discussed in Chapter 1.

 

I take the terms lower futtocks and first futtocks to be synonymous, but consistent usage would have been better. 

 

Ed


Edited by EdT, 09 March 2016 - 03:05 PM.

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#39
Capt.Bob

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Ed,

Thanks for the confirmation.  I've got too much invested to screw things up now.  Also, the background information is always interesting.

Bob


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Bob

____________________________________________

Current Build:  Mantua "USS Constitution - 1797"

 

Pending:  Model Shipways "USS Constitution"

 

Completed:  Model Shipways "USF Essex -1799"

                    Model Shipways "New Bedford Whale Boat"

                    Billings "Zwarta Zee" (RC)

                    BlueJacket "Sequin" Tugboat (RC)


#40
Capt.Bob

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Ed,

Page 61: Figure 3-39  Should be: Figure 5-39

 

Pattern 29a: The 3rd futtock is sided as 10".  Is this accurate?  Everything else is sided as 11"

 

Bob


Bob

____________________________________________

Current Build:  Mantua "USS Constitution - 1797"

 

Pending:  Model Shipways "USS Constitution"

 

Completed:  Model Shipways "USF Essex -1799"

                    Model Shipways "New Bedford Whale Boat"

                    Billings "Zwarta Zee" (RC)

                    BlueJacket "Sequin" Tugboat (RC)





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