Extreme hull planking towards the stern on full size ships?

[rtropp]

I have seen a number of models that require fairly extreme plank bending as the hull planks approach the stern.  I looked at a number of models including the Licorne by MTaylor as well as others, both scratch and kit built. 

 

Were these bends actually made on the full size ships?

 

Thanks,

Richard

[allanyed]

Richard

The planks did bend to the extreme, but they were not just straight pieces of wood forced in place.  Spiling each plank was necessary to give the right shape that could then bend properly.  A planking expansion showing the shape of each plank before they are bent will give you a better idea of what I am writing.  If the attached is not clear, this picture and several other expansion drawings can be found on the National Maritime Museum collections site.  When the site comes up, in the search box type planking expansion.

 

Allan

[druxey]

With all due respect, the planking expansion shows the pattern of planks, but they are distorted in the projected view. For instance, in the topside of the illustration of Squirrel, the midships planks actually curve in the opposite direction ('smiley'). Otherwise, virtually all the hull planks are cut on a curve, as you say.

[captain.jerry]

I know that this type of drawing is a common part of a ships descriptive drawings but I am not clear what its purpose is.  It clearly does not show the shape of each plank as if it were laid flat before bending.  The boards closest to the keel are most nearly correct in this view but the higher boards are distorted according to some drafting rule that is not clear.  If you were to cut each board according to this drawing and them glue them together edgewise, you would produce a flat surface, not the curved shape of a ships hull.

 

Jerry

[druxey]

Captain Jerry: the purpose of the expansion is to show:

 

a. the length of each plank 

b. shift of the planking butts

c. ensure shifts of the inner and outer planking are offset from each other

Edited July 12, 2015 by druxey

[mtaylor]

Richard,  I hope you're not confused by my efforts.  I'm on the learning curve here.  Yes, the real ones did have some extreme bends.   Mine are/were over extreme as I didn't have the curve of the tuck right.  I'm still working on this area, btw.

[rtropp]

Mark,

It did not take any help to get confused, I am pretty good generating my own confusion.

 

My interest in the real practices of plank bending began during my first attempt at the 18th Century Longboat .  Some of the bends were so difficult that I could not do them correctly in a double size scale. 

 

I noticed that a number of builds required extreme plank bending and the number of different practices and devices for bending are huge.  So I guess I just started wondering how did they do this in real practice.

 

In researching I found a couple of mentions of steam boxes at the ship yards, but none really explained how the bends were accomplished after steaming.  (My image of a huge plank bender 30 feet tall did not help;-). I do have a few books relating to full scale ship building but have found nothing that gives my a visualization of a plank actually being bent.

 

I am still looking for something like that and if anyone has any sources for the full size plank bending process used in the 18th/19th century I would appreciate seeing it.

 

Thanks all

Richard

[mtaylor]

Richard,

See if you can find Dodds & Moore Building the Wooden Fighting Ship.   It's a pretty easy read and has lots of good info from how selected and managed the forests, to raising the frames, bending the planking, even iron mongey. 

 

Basically, the planking was put into the steamer for 1 hour per inch thickness plus (as I recall) one hour for the plank.  It would have been already spiled when it went into the steamer if needed.   They would haul it out and put it on using something like jackscrews to bend it into position and hold it while it cooled. 

[Jaager]

Lets' say you have a hull planked except for one last plank in the bow area so that the plane of the frame surface bends toward the stem.  The line of the planking  strake bends up with the sheer.

 

Take a 3 x 5 card and place it over the hole to be planked.  Rub a pencil over the edges of the surrounding planks to get the shape on the card.   Cutting the shape of the plank from the larger card is  spilling ( spoiling the rest of a good board as waste).  You now have the plank shape.  To get it to lay flat against the surface of the frames and not want to spring back up, this is what steaming is for.

[captain.jerry]

Captain Jerry: the purpose of the expansion is to show:

 

a) the length of each plank 

shift of the planking butts

c) ensure shifts of the inner and outer planking are offset from each other

 

Thanks, Druxey. That makes good sense.  The visual appearance of the drawing seems to be trying to say something more but your explanation clears it up for me.

 

Jerry

Edited July 11, 2015 by captain.jerry