Deadwood

[Don Case]

I've noticed in drawings that the deadwood is usually made up of two or more pieces. Would this be a set plan or was it just fill up the bow and stern with whatever was kicking around? Of course the end result had to be the right shape but did it matter how they arrived at that shape.

[jlefever]

I'm sure you'll get other opinions on this question but my two cents worth.

 

Deadwood consisted of important structural members but at the time most wood ships were built engineering as we think of it didn't really exist. Instead skilled ship builders (we hope they were skilled) surveyed the material on hand selecting the right sizes, grain and supposed strength from which to cut the timber members. The wood had been harvested with care, selecting trees who's trunks and limbs were sound and strong from which members could be cut without flaws while respecting the natural wood grain.

 

Further important framing members would be fastened to the deadwood (cant frames) so the material needed to be sound.

 

So perhaps the answer to your question, the material was often selected from wood on hand but with with very specific attention to it's form, soundness and strength. it wasn't a casual process.

 

Jim

[allanyed]

JIm has an excellent point as to selecting pieces of timber.  Regarding the deadwood aft, I looked through about 50 inboard profile drawings in the NMM collection over half that I looked at show no individual pieces.    The rest all show the same curved piece as seen in four examples below but no others which leads me to believe there indeed was not set pattern.

 

Goodwin goes into some detail on pages 12 and 13 of The Construction and Fitting book.  The deadwood was shaped to generate the correct underwater shaped of the hull and the height depend on where  a relatively sharp  full hull form was required. The fore deadwood was not always present and was mainly where a sharper entry was needed and fitted directly over the boxing joint.  He goes on to say that the aft deadwood was made up of about eight pieces.  He gives a description of the shapes of the lower pieces and upper pieces as well.  He also states that the number off individual pieces varied depending on the builder for this area was a good opportunity to utilize large offcuts of timber to minimize wastage.   

[Don Case]

Thanks guys. 

Allan- a follow up. On the pictures you posted the rudder has that notch close to the top. Some ships have it and some don't. Is it there for a reason?

[allanyed]

Don,  Not sure what notch to which you are referring.  Can you mark the notch on one of these or some other picture showing the notch?   There are normally two square holes through the rudder.   I have always assumed one is for the tiller that is set up with the ship's wheel and the other for a hand controlled tiller in the event the first is shot away or otherwise out of commission.  I may be off base on the reasoning for two, so would welcome contemporary information if anyone has it.  

 

Allan

[Don Case]

This little divot. I was thinking maybe a restraint to hold it down.

[bruce d]

This may help. Below is a detail from a drawing showing how sternposts were connected to keels in Woolwich shipyard (circa 1820). The subject is a 74 gun ship.

 

 

A bit later than your subject Don, hope it helps.

[allanyed]

Don

The rudder was generally made in several pieces and this point is usually the place where the aft most piece (backing piece) fays to the center piece.   I THINK the hance is more or less decorative and is just an extension of the backing piece.   There is actually a lot in the making of the individual pieces as well as how the hinges, reinforcing bands, and eyes/spectacle plate for emergency steering.

 

[druxey]

I agree with Allan on the slightly decorative upper end of the backing piece.

[bruce d]

I thought that feature at the top of the rudder was to allow a yoke to be dropped in place for emergency steering.

[allanyed]

Hi Bruce,  

The spectacle piece is where chain or rope is attached for the emergency steering.  The following is a basic sketch.  It is typically located just below the lower hance on the aft part of the rudder.

[bruce d]

10 hours ago, bruce d said:

I thought that feature at the top of the rudder was to allow a yoke to be dropped in place for emergency steering.

I was totally wrong. Turns out the cut-out, called a hance, indicates a step in the dimensions of the rudder.

From Steel:

 

 

This is pretty much in line with the comments from experienced members earlier in the thread.

[bruce d]

Also, this should be useful to understand the placement of a hance.

From 'Naval Architecture' by John Knowles 1822: