thowen

Blockading Brest during the Napoleonic Wars. A Brig brings in a captured French Lugger.
W/C  14” 10”

Fantastic. Very good work. 

Fantastic work. Espezially the way to build gratings is very useful for me. Thanks for showing.

Nice work. What wood did you use for the planks?

Looks very good.

Nice start.

Young America - extreme clipper 1853
Part 4 - Webb’s Young America

Well, they say that every good plan eventually degenerates into hard work. The research and planning for the model has been fun, but now it is time to get down to business. That does not necessarily mean getting right into the workshop, although apart from the frame process tests discussed in Part 3, I do hope to start forming the keel in a week or two. Right now there is a ton of frame lofting to do and sometimes that can get tedious. With 80 frame pairs, totaling 160 frames, there are a lot of patterns to create. Please be patient.

In Part 3 I had intended to discuss Young America, and my choice of her as a subject, but I inserted the framing process work instead. So, I will discuss YA here while I take a break from lofting frames.

Webb
William H. Webb was widely regarded as the premier American shipbuilder of the mid-19th century period. His father Isaac Webb took over the New York shipyard of Henry Eckford in 1825 and operated it under the name of Webb and Allen until his death in 1840. During that time, 23 ships – from cutters to packets were built. In 1840 William Webb took over the yard. Over the next 30 years, 135 ships were built – packets, clippers, steamers, barks, ironclads, and of course, extreme clippers – 9 of them. Following Celestial and Gazelle, the third.of these was Challenge, launched in 1851. The purchasers single requirement was that Challenge should be the finest and fastest merchant ship in the world, regardless of cost. At 252’ feet she was the largest extreme clipper to be launched to that date. Comet at 241’ was launched two months later. There were four more before Young America in 1853 – the ship that Webb considered his masterpiece. He knew the extreme clipper era was ending and that YA was the last he would build. He went on to build many more ships through 1869. In later life Webb turned to philanthropy, starting a school of marine architecture for boys of limited means. To this day, tuition at Webb Institute is free to qualifying applicants.

Young America

Young America was named after a broad, popular cultural-political movement that flourished in pre Civil War America. The movement advocated democratic reform, free trade, expansion and similar themes. It was a largely urban, middle class movement that became associated with the Democratic party and Stephen Douglas. It paralleled similar movements in Europe.

Some design particulars:
~243’ long od, 43’2” extreme breadth, ~26’ depth of hold
1961 tons – old measure
20” floor deadrise (9 deg)
deadflat forward of midpoint 25’
swell of the sides (tumblehome) 20”
3 decks
circular stern
cost $140,000

Excuse the approximate numbers on her size. There seems to be a variety of measurements reported and due to lack of standardization, it is not always clear what they are. Fortunately the original offsets (see below) ensures that the model will be correct. Other features will be described and compared to other similar ships as they occur later in construction.

I include deadrise in this list because it was considered a key variable in improving speed. Of course as the angle of the floors increased, hold capacity decreased, so the pronounced deadrise of up to 20+ degrees that was employed on the early extreme clippers clearly emphasized speed over capacity in these ships. As the period advanced, bottom shapes became more flat, without an attendant loss of speed. At 9 degrees YA is a good example of the evolved design.

The key structural issue in these ships was the prevention of hogging – the downward deformation of the hull at the ends – sometimes to the point of failure. The problem occurred in wooden ships because of reduced buoyancy at the ends due to less hull volume at the bow and stern. The long length and the sharp entry and run aft in these ships severely aggravated the problem. The obvious solution was to increase hull strength by various means – huge keelsons, heavy inboard planking (called bilge keelsons), various forms of triangular bracing, anti-hogging chocks, diagonal iron lattice-work bolted to the frames, kneed pillars, and generally heavy construction - to the point of reducing hold capacity. Relative to the competition, Webb employed these features with a lighter touch, generally keeping scantlings smaller. He also employed some innovation in going to variable frame spacing with frames spaced further apart toward the ends of the hull where the smaller sections required less structure. This is said to have reduced the dead weight of the structure at each end by up to 25 tons – a substantial relief of the hogging strain effect. The long life of Young America (and others) is a testament to this good engineering.

Availability of data on Webb’s ships is limited to books of plans from his papers for some of his ships. Data for Challenge is fairly complete, since at her launch detailed descriptions were printed. For Young America, less original data is available.

Building a fully framed Young America would not be possible for me without the work of William L. Crothers, specifically his recently published (1997) The American Clipper Ship, Characteristics, Construction, Details. The book is a thoroughly researched tour de force on clipper ship construction. In it he has reproduced Webb’s original table of offsets for both Young America and Comet – essential for producing hull drawings. He has also included substantial basic scantling information for a variety of ships. Based on the assumption that Challenge, Comet and YA would all be similar in structural design, I believe an accurate framed model design can be made forYoung America. Having reached this conclusion, I made my choice to proceed. Crothers also published model plans for a number of ships under the name Sea Gull Plans. The plans for YA (1:96) do not include framing or structure, but will be useful for deck arrangements and rigging. I have also used his similar plans for Challenge and McKay’s Lightning for reference. I have acquired and studied a variety of other sources, but in the main, Crothers has nicely collected most of the useful data – and has usefully referenced his sources in detail.

Below is an image of the CAD body plan from Webb’s original table of offsets. This provides a good description of the hull shape. It is very different from my previous model of Naiad and ships of her type. The method of creating the body plan was also much different. Gone are the heights and breadths of rising, the circular sweeps and points plotted on diagonals. It is possible that a half hull model was made first and the waterline/butt line offsets taken from that to loft the ship. This was a common practice.



This body plan is a starting point for the frame lofting. It shows only profiles at primary station lines. To this drawing I have added all of the intermediate frame profiles as well as profiles between these to permit beveled frame patterns to be lofted. The intermediate profiles were plotted from points measured on a half breadth plan constructed from the original table. That body plan is shown below.



The cant frame profiles are not shown in this plan. The square frame lines are extremely close together, especially near midship. Fortunately, only the computer has to see them.  The diagonals on this plan were added only to set the height of the frame joints in fair lines. I do not believe the American builders paid too much attention to this, but it will make a neater model.

In addition, a table of scantlings is being progressively constructed from various sources.
 
As proof that there will really be a model starting soon, I have included the following photo of the old Naiad building board sporting the framing plan for YA. The shipway is just long enough.




Ed

What a beautiful ship. Very nice build.

What a beautiful model. 

It's great to see what you're doing from the de'agostini model.

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              see you soon friends
 
rekon54

1588 – The Spanish Armada, with 130 ships and 30,000 men, sets sail from Lisbon heading for the English Channel. (It will take until May 30 for all ships to leave port).
1905 – Russo-Japanese War: The Battle of Tsushima ends with the destruction of the Russian Baltic Fleet by Admiral Togo Heihachiro and the Imperial Japanese Navy (for more see http://en.wikipedia.org/wiki/Battle_of_Tsushima).