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trunnels (tree nails) vs metal nails use

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I'm making a 3d model of a British 6th rate ship circa 1720 and I have a question regarding the locations where trunnels were used verse iron/bronze nails.


I know all (?) exterior planks were fasten to the frames by trunnels.  Was there anything fasten on the outside using iron/bronze nails?


Were the interior planks also fasten to the frames using trunnels? 


Were the deck planking fasten to the deck beams using trunnels or iron/bronze nails?


I know the knees were fasten using large iron/bronze bolts.  Where else were the iron/bronze bolts used to fasten stuff?


Speaking of "iron/bronze" bolts, what's the difference between iron bolts and bronze bolts?  Was it distinctive of different periods, areas of the ship, nationality, .etc?


I'm sure the keel was fasten together using iron/bronze bolts.  Is it safe to assume these were capped with false trunnels?


I know this is a lot of questions, but it seems there's just isn't a one stop place for all the answers.  Thanks!



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As is now, the choice between iron and bronze is based on a trade-off between costs and corrosion resistance (life).  However, if the corrosion can be controlled, then iron would probably the the best choice.   I'm not sure what grade of iron would have been used, so I can't say there would be a strength advantage for either metal.


Bolts were used extensively in the keel and skeg - anywhere where the larger timbers needed to be connected.  Not sure of building practice in early 1700's but, later, bolts were used to hold the clamps to the frames.  


Also, they were not bolts as we know them, with a thread on the end(s) for a nut.  The fastening was a clinch ring (washer) or plate put over the end of the "bolt" and then the end was clenched (flared over), so they are more like rivets than bolts.  In a sense, a treenail is a wooden rivet.


Bolts that come out the bottom of the keel are covered with a shoe board.  Other places for bolts that would be exposed on the exterior  would be the channel iron fastenings, and other anchor points for rigging.  

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Take a look at William Sutherland's Shipbuilding Unvail'd, written in 1717 and very applicable to your project. The hyperlink is to the free online copy. Pages 75 to 96 of the text (57 to 68 on the online viewer) include a template for a British ship's contract. Unfortunately, the dimensions are left blank, but at least it will tell you which components use bolts, which use nails and which use trennels. The 1719 Establishment also has some information on bolts (including diameters). Peter Goodwin's Construction and Fitting of the Sailing Man of War has a transcription in the appendix, and Allan Yedlinsky's book Scantlings of the Royal Navy includes the Establishment data as part of the tables.


Hope that helps,


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I am not aware that bronze bolts were ever used, but then I am not necessarily an expert on 18th century shipbuilding.


Copper was used extensively for smaller fastenings.


While mechanically, from the point of of tensile strength the use of (wrought) iron bolts has many advantages, it is problematic in conjunction with certain woods due to their acidity (tannic acid) contents. This makes both, the bolt and the wood rotting. I believe certain oaks were not considered suitable for use in conjunction with iron fastenings.


Iron bolts certainly would not be used in places, where they would be exposed to sea water. If the bolts, due to their location would be exposed, they were countesunk and the hole would be plugged with a wooden plug. This can actually look like a tree-nail from the distance, but the plugs would not show end-grain, as they would be cut from a plank (as for the decks) to have the same grain direction as the surrounding wood.


Iron-fastenings can also not be exposed to seawater, when the ship has copper-, or Muntz-metal-sheathing, as both are electrochemically more stable and would lead to fast anodic corrosion of the iron bolts.

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I have actually learned a lot since I've first posted my question.  Ship building is very fascinating.  All too often we as a society believe we are intellectually superior to past generations with our "smart phone", our cars that will automatically stop and landing probes on meteors speeding thousands of miles per hour through space.  In reality our collective knowledge built by past generations is relative to our environment and our goals, but we are no more intellectually superior than past generations.


Anyways...I meant copper bolts, not bronze.  The information was fuzzy in my head at that point.  I wish there was a simple diagram pointing out all the different materials in a cross section.

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" ... I wish there was a simple diagram pointing out all the different materials in a cross section." - Past generations used to make beautiful technical drawings/lithographs, at least for publication purposes, where the different materials were colour-coded. Typically iron/steel was laid out in blue, brass/bronze/copper in yellow, wood in light browns, etc.


Having read through the Greek philosphers of old (and various even in the original language) at school and later, I came to the conclusion long ago, that most fundamental thoughts have already been thought some two and a half millenia or so ago - and the thinking may have been much older than the writing. The challenge today is to keep an overview over the available knowledge - or rather to have meta-knowledge, to know where to look up things, when you need them. This in itself can be daunting task in the professional life and a hobby alike.


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