Tuning Copper sheathing

[allanyed]

Hopefully the odd title will attract some attention and an answer to my question.   A question was asked regarding coppering between the false keel and keel on Euryalus (36) 1803 so I did some digging and found very little except the following from a contract for two of her sister ships, the Astrea and Curacoa.    It is relatively clear, except, what the heck is tuning up copper?  I know the term as used in a musical instrument or a fist fight, but not in this case.   Note that the instructions to use tar and hair in the scarphs was struck out in the contract.

 

The False Keel to be of one Thickness 6 inches thick, to make the Main and False Keels together 1 feet 5 inches below the Rabbit, to give Scarph to the Scarphs of the Main Keel to be laid with Tar and Hair, and sufficiently fastened with Nails and Staples.  The Sides and Bottom to be filled or sheathed with Copper and to have thin Copper put between the Main and False Keels all Fore and Aft properly tuned up and fastened, the labour to be done by the contractor.    

[Charter33]

Might it be referring to having the copper sheathing hammered or beaten to final shape to match the timbers ie. fine tuning or 'dressing' the sheet for a good fit?

[Jaager]

It also may be a typo -  maybe turned up was intended?  Indicating that the plates were to be attached to the keel?

[druxey]

I think Jaager is correct: turned rather than tuned. Sometimes transcribing period script is difficult.

[Snug Harbor Johnny]

  You can tune a piano, but you can't tune a fish ...

 

[bruce d]

Allan, is there any chance that the old script says 'shined' rather than 'tuned'?

[allanyed]

6 hours ago, druxey said:

I think Jaager is correct: turned rather than tuned. Sometimes transcribing period script is difficult.

You may be right, but I am researching further.  The copy of the original came from NMM back around 2010, maybe earlier but as it was from circa 1803 it was a typeset canned contract with blanks to fill in dimensions.  I could very well have mis-typed it when transcribing.  Unfortunately the copy of the original has gone missing what with several moves in the interim.   I think I know where there is a copy of the original copy and will try to find it.

 

Thanks everyone

 

Allan

 

 

Edited January 10, 2023 by allanyed

[James H]

4 hours ago, druxey said:

I think Jaager is correct: turned rather than tuned. Sometimes transcribing period script is difficult.

 

I'm not too sure. I used to work in engineering and I heard panel beaters/fitters refer to material as being 'tuned', meaning made to properly fit.

 

But of course, this didn't refer to hull coppering. 

[druxey]

Interesting use of the word 'tuned', James. 

[allanyed]

Sort of like tuning a steel drum, where they pound the top in various places and thicknesses to get different notes.

Allan

 

[Snug Harbor Johnny]

  OK, I'm trying to give the quoted text (pasted below) a bit of thought, and can think of a couple possible explanations that could encompass a missing punctuation mark - and old pronunciation (dialect?).  The text:

 

The Sides and Bottom to be filled or sheathed with Copper and to have thin Copper put between the Main and False Keels all Fore and Aft properly tuned up and fastened, the labour to be done by the contractor.    

 

  Now there may be TWO tasks or processes described separated by "and" - without a comma after the first Copper.  So one application is to sheath the sides and bottom in Copper,  ... and (a second specification) to have thin copper (presumably thinner than the copper for the sides and bottom) put between the Main and False Keels (I'm not quite sure what this is, but likely what we take as the 'keel' (made wider at the bow by the presence of the false keel).

 

  Now 'tuned up' could mean (in dialect) what we'd pronounce 'turned up' - meaning one or more edges.   For instance, tin flashing (formerly lead) has been used for slate roofs - and there is something called a "slaters' edge" on the flashing against the house, where the top edge is folded over to make it harder for water to creep farther than the tops of the overlapping flashing.  So perhaps there was a way in treating the copper material that 'wrapped' the keel from stem to stern (just a guess), where (starting astern) - the forward edge of the keel sheathing has the edge folded back a little (1/2" to 1"), so the rear edge of the next piece (having been folded under) engages the last piece and can be tamped down flat with a mallet before nailing.  This might explain why a somewhat thinner copper would be used in this application due 4 layers on the leading & trailing edges (after assembly) as well as the sharp bends of the keel itself.  Note that the forward piece lays over the one behind it like the scale of a fish, so the join would resist coming apart.

 

  The second guess on 'tuned' might be a typo for 'tinned' - which (with often haphazard and variable spelling in ye old days) might have normally been spelled as 'tined'.   In the American Colonies, the word 'horse' was often spelled 'hors' - perhaps a comparable analogy to 'tined'.  Now "tin" is thought of as thin sheet iron (steel, actually) that has had a surface treatment whereby the strip off a roll is passed (dipped) through a fluxed bath of molten tin.  This leaves a very thin plating of solidified tin (actually 95%tin and 5% antimony, so that the tin does not crumble away under very cold conditions - like around zero Fahrenheit).  This was made into all kinds of 'tinware', and was very resistant to rust - which otherwise would quickly oxidize through the thin steel.

 

  But 'tin' can refer to any thin sheet metal, so after the specification of copper sheets to cover the ENTIRE keel (at & below the waterline) as well as the sides and bottom (the whole labor generically falling under 'tin work'), we could clarify with a dash to punctuate:  'The Sides and Bottom ... the Main and False Keels (-) All (to be) Fore and Aft properly tinned up and fastened ...'

 

  In other words, the rectangular sheets are to be oriented fore and aft (as opposed to vertically).  I suppose if an apprentice started to do it the wrong way (bass ackwards), an experienced hand might say,  "Somewhere a village is being deprived of an idiot."

[bruce d]

Allan, have a look at the phrasing in the description of 'LEAD TO BE PUT BETWEEN THE KEELS' in this contract for Squirrel 1785:

[druxey]

'Turned up' it is! Thank you, Bruce.

[Snug Harbor Johnny]

  Interesting that lead was specified in a contract to go BETWEEN the keel and the false keel.  Lead and copper don't appear to have a galvanic action, as lead solders easily onto clean copper - as does tin.  The inside of copper cookware were often 'tinned' with tin so acidic and other food ingredients don't corrode the copper or produce verdigris (copper sulfates and such).  

 

  Ergo, in the first specification in this thread, perhaps the copper to go BETWEEN the keel and false keel was to be tinned (easy to do with copper, and tin-lead alloys often have a lower melting point that either constituent), thus eliminating the need for separate lead sheets.  It is unknown why lead sheets were sometimes used (or tinned copper), unless it was to clad the back edge of the false keel (for protection from marine organisms) BEFORE it was tree-nailed to the keel - thereafter sheathed in copper from the join to the cutwater.

 

  The second specifications say that the keel is to be coppered before the false keel is added.  So if bare wood was put against the copper keel, there might be a 'chink in the armor' so to speak.

[bruce d]

Once coppering of hulls was recognised as a good thing the technology was evolving constantly. Many combinations of materials were tried and Master Shipwrights were often, shall we say, 'economical with the truth'. What also complicated things was that few people actually understood what happened to the copper in seawater and how it reacted when different metals were present. 

This is a good source, previously posted but worth recalling:

The_Introduction_and_Use_of_Copper_Sheat.pdf

 

 

[allanyed]

THANK YOU BRUCE!!! It turns out it was a typo on my part afterall.    

Cheers

Allan

[Snug Harbor Johnny]

15 hours ago, bruce d said:

Once coppering of hulls was recognised as a good thing the technology was evolving constantly. Many combinations of materials were tried and Master Shipwrights were often, shall we say, 'economical with the truth'. What also complicated things was that few people actually understood what happened to the copper in seawater and how it reacted when different metals were present. 

This is a good source, previously posted but worth recalling:

The_Introduction_and_Use_of_Copper_Sheat.pdf 2.01 MB · 6 downloads

 

 

  Thanks, Bruce ...  Figure 1 of the paper clearly shows a sheet 'sandwiched' between the keel and the false keel - and the edges are indeed turned up to cover where the copper ends on the keel.  likely this was to allow nailing on the sides through both lead and copper  along the strip.  With the use of lead to cover bolt heads, etc. (mentioned elsewhere in the paper), the material between the keel and false keel was likely lead - as specified in the contract language posted earlier in this thread.

[wefalck]

Before reading all the others' comments, I thought immediately the idea was to ensure that both, keel and false-keel were properly wrapped in copper. The false-keel was a sort of expendable item, meant to protect the actual keel from damage. In case it was (partially) ripped off by grounding etc., the keel still needed to be properly protected from this nasty digging animal.