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Looking for the Correct Sequence and Terminology for Deck Plank Butt Shift


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Hi folks,

 

I am trying to determine the correct sequence of the butt shift for deck planking.  I have done a search but find several references and cannot find a contemporary (1855) reference that gives the sequence.

 

I am using a four butt shift, so what would be the correct sequence please? I have seen it expressed as  5-2-3-4-1 and 1-3-5-2-4 but what does this actually mean?  I think the numbers are applicable to the plank no, rather than the butt number - have I got that right?  What I am trying to get to grips with is how this translates into practice - that is, if I start with a central plank, say #1, and then the next plank would be set back (butt shifted) a distance in a particular pattern of stagger.  In previous models I know I have got this wrong by just staggering them in a regular sequence rather than the above sequences.  By standard or regular stagger I mean that if #1 is the start, and the stagger is 5 feet overlap, the next would be 5 feet back, then the next another 5 feet and the fourth another 5 feet, the the sequence starts again. 

 

I have read the former sequence(s) is supposed to provide greater strength/less chance of splitting along a common line, but wouldn't a standard/regular sequence provide the same if they all land on a deck beam?  Seeking an education :)

 

Can anyone please provide the correct terminology for this, and explain (in dummy's language) exactly how the stagger is supposed to be.  Also, is it  different between Service and Merchant ships?  

 

Many thanks

 

Pat

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1 hour ago, BANYAN said:

I am using a four butt shift, so what would be the correct sequence please? I have seen it expressed as  5-2-3-4-1 and 1-3-5-2-4 but what does this actually mean? 

The only way I can see that there can be 5 numbers in a four butt shift is if the four refers to the number of planks between two planks having their butt on the same beam.  The repeating sequence actually involves five planks.

The first picture above,  numbering from the top down =  Beam 1 - beam 3 -  beam 5 - beam 2 - beam 4

 

The second, top down =  beam 1 - beam 4 - beam 2 - beam 3

 

 The American "Lloyds"  ASA 1870   " No butts of adjoining plank should be nearer each other than the space of two beams ( when a stake intervenes the distance of one beam will be allowed).  No butts should meet on the same beam unless there be three stakes between them."

The second picture fails that rule.

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8 minutes ago, Jaager said:

" No butts of adjoining plank should be nearer each other than the space of two beams ( when a stake intervenes the distance of one beam will be allowed).  No butts should meet on the same beam unless there be three stakes between them."

The second picture fails that rule.

Okay, maybe I am being thick. How does it fail? There are three planks between the butts and three beams betwen the butts: what am I missing?

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23 minutes ago, allanyed said:

if the drawing carried over a few more beams and strakes as I have added on the sketch below.

Allan

Me too, but now I am alert I see another 'fail' in the second sketch in post#2: planks 1 and 2, right hand side, also incorrectly spaced.

 

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Sketch 2, row 1 and 2, from the top:

2134085068_Buttshifts.JPG.356c7bf0d42c04b6cff4fcf1433b424b.JPG

Right hand side, the butts are one beam apart. I have looked at the original in Anatomy of Nelson's Ships countless times and didn't see it even when I was writing my 'program notes' for the deck I am laying out. Whether I would or would not have picked it up when cutting holly, who knows?

All I can say is 'better late than never'.

Thanks Jaager.

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Bruce,  I don't know if the second sketch from Goodwin is correct or not, but it is consistent in the layout and I assume it is correct.  Sorry, but I keep looking and still do not see any error in the  rows 1 and 2 in the lower sketch.     Note that this is the same pattern in the TFFM Swan class series for the upper deck.   The three butt shift pattern does not form a straight diagonal of seams like the 4 butt shift, but the pattern that is shown does repeat along the length of the deck.   And then things can get a little more difficult for the four outer most strakes if top and butt planking is used for strength to support the guns.    Fun stuff.     

Allan

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9 hours ago, Jaager said:

" … No butts of adjoining plank should be nearer each other than the space of two beams ."

That is the part. I have now looked at a few examples and wonder (as mentioned in post#12 above) if it was (A) an American rule and (B) ...

 

9 hours ago, Jaager said:

The American "Lloyds"  ASA 1870

… is not something I have used but does the '1870' indicate a different date and practice?

I don't know the answer but someone does. If there is an error in Longridge's Anatomy of Nelson's Ships we should nail it down.

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The ASA ( now ABS ) published their first set of rules in 1870.  They came into existence in 1862.  Their initial focus was the qualifications of ship captains.  I would be more than surprised if their rules were not a direct swipe from Lloyd's of London, who have been doing this since the middle of the 17th C. 

We do not have a problem with getting timber that is long enough.  Using planks that are longer than 40 feet - southern US coastal Pine was tall and straight - until they cut it all down  - and before 1775 the RN could use it also -  anyway - longer than 40 feet in scale is a more common mistake.  

Why not use 40 feet as the length, and a proper 4 strake pattern?  

It would be best practice for any country.  It would be what they did if they could or were not running a con.   The strength of wood when exposed to the force of the sea is not subject to a national fashion or the century.  When larger wooden hulls were first being developed,  they learned pretty quickly when they got it wrong.  The sea does not forgive foolish mistakes.

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Thanks for the great response and continued discussion.  I am now more the wiser WRT to the stagger being applicable to the landings on the beams rather than length of plank overlap, and that there was a two beam overlap. 

 

I remain confused with the stagger pattern however; and, if I am not missing a basic point, may have differed for the English rules. 

 

What I am now trying to understand is whether there was an 'offical' or even 'rule-of-thumb' for the stagger  sequence?  I posted two stagger sequences ( 5-2-3-4-1 and 1-3-5-2-4) that I have seen in my initial post; can anyone provide better guidance on which was used (or if both).   What confuses me most is the second of 5 butts in the sequences  - at the moment I am simply assuming that 5 and 1 (in the first sequence) are butts landing on the same beam, which would be a 4 butt shift. 

 

However, the second sequence would not hold to this interpretation.  The only thing I can put this down to is that perhaps, with time, as the width of the planks dimished as suitable timber became harder to source, that a 5 butt shift was needed to get adequate separation along the same beam?  In 'Victoria'  The maximum plank width was specified as 7" but measuring the planks visible in the two photographs showing deck planking, the average plank width was 4.75".

 

cheers, and many thanks again for the great discussion.

 

Pat

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13 minutes ago, BANYAN said:

stagger sequences ( 5-2-3-4-1

I would not insure that one,  or pay a private yard if it was a navy contract build.

2-3-4  are  on adjacent beams and touch. So is 1-5  At least they are not all butting on the same beam, or every other one, as I saw recently.   But it is likely a mistake in any case.  With a sequence with 5  and 1  at the ends, it can never work.

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It is very possible that we have been mixing our apples and oranges. I certainly have, because the English practice did not reflect the American rule quoted.

The original question concerned an 1855 ship, HMCSS Victoria. Jaager's answer quoted text from an American rule of building from around that time. However, the illustration which first appeared in post#2 is from Goodwin's The Construction And Fitting Of English Men Of War 1650-1850, clearly a work on English ships.

According to Langridge, Anatomy of Nelson's Ships, and David White Traditional Wooden Shipbuilding (pt 9),  the illustration in post#2 from Goodwin's The Construction And Fitting Of English Men Of War 1650-1850 is correct. It is worth pointing out that all three of these works mentioned are based on original sources and not rehashhes of the work of others. I do not have access to their original sources but accept their findings.

To quote White (Traditional Wooden Shipbuilding (pt 9) Model Shipwright 63, page 56):

'...(the planks) should be worked to a three plank shift, which meant that there should be three whole planks between any two butts on the same beam. Second, the butts had to overlaunch or be shifted at least 6ft. That is to say the butts in any two adjacent planks should not be closer together than 6ft.'

He illustrates his description with a drawing which I have recreated below. It shows two butts on adjacent rows of planks and they are 6 feet apart, hence they conform to the requirements. The '6ft overlaunch or shift’ is the rule that he cites, not the number of beams. He does not quote any rule at any point that I have yet found which requires a minimum number of beams between butts; to the contrary, he describes what to do when butts are on adjacent planks. He also tells in detail how to work around hatches, deck fittings etc but that is beyond the original question. So, if the ship is being built to English rules and the layout of the deck and the shift pattern calls for it , keep six or more scale feet between butts when on adjacent planks and you are ‘legit’, whether it is a three, four or five butt shift.

image.png.53fced2cdec49c57ae5a9646b6696ce7.png

It seems that the clarity of the American rule is admirable but does not reflect English practice.

HTH

Bruce

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On 5/18/2020 at 7:28 AM, BANYAN said:

I have seen it expressed as  5-2-3-4-1 and 1-3-5-2-4 but what does this actually mean? 

I find the simplest way to think of these planking schemes is as ratios of lengths. 

 

Longridge in his Anatomy of Nelson's ships uses the sequence 5:3:1:4:2, and in his case he's using inches. He was building Victory to 1:48 scale, so a 20 ft deck plank was exactly 5 inches long. If he started a line of decking with a five inch plank then every plank in that line would be five inches for as long as possible. The next line up, he started with a 3 inch plank, then finished the line with 5 inchers. The next line up started with a one inch plank, the next 4, then 2 then back to 5. Alternatively, if you work from the other side of your original 5 inch plank, the sequence becomes 5:2:4:1:3, Thus:

 

Planks_edited-1.thumb.JPG.dd4358327d09e58988dccdec4d354c0b.JPG 

This gives you the four step butt planking and avoids butts on adjacent beams. Simples.

 

If you're working to a different scale and/or plank length, you can still use the same ratios. So on my current 1:64 Speedy build a 20 ft plank works out at 95mm. So my sequence/ratio is 95:57:19:76:38.

 

Derek

 

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Thank you again Jaager (Dean), Bruce and Derek, much appreciate the feedback.  No matter the country, era etc, this has been very interesting and I am learning a lot from the discussion. 

 

Bruce is correct in identifying my particular period of interest being the mid-19th century, and by looking at the details within several of the posts I thinks the basics I have gleaned are that the butt shift and stagger pattern should :

1.  be a three or four plank shift

2.  the beam spacing (and to a lesser extent the length of the planks) govern the length of the overlap

3.  adjacent planks should have at least a two beam (apart) stagger/overlap, which determines the stagger pattern

4.  the more appropriate pattern for me (based on the Longridge diagram provided by Derek) would be 5-2-4-1-3 (if reading from plank 1 and downward), or 5-3-1-4-2 if reading from plank 6 working upward)

 

This would ensure the greatest separation of the butts along the same beam but also ensure at least 2 beams length of plank between adjacent plank butts; providing the greatest strength in the planking along any beam.  This is of course general in nature, as many plank lengths will have been interrupted by deck openings etc.

 

Thanks again all

 

Pat

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After many builds and following many blogs I only recently noticed via superb scratch builds of Le Feuron  ,Bonhomme Richard and Renommee that deck planking in these cases is curved and not parallel joggled. Is this a basic difference between French and English/Dutch?  The decking plan of the Bonhomme Richard (Boudriot) doesn't seem to have a discernible pattern.  Why the national difference? Function? ease of building or national character (?romantic against pragmatic)? 

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14 minutes ago, stuglo said:

deck planking in these cases is curved and not parallel joggled. Is this a basic difference between French and English/Dutch? 

Hello Stu,

I asked a question some time ago that addressed the same point:

The subject was bigger than my original question. Hope it is helpful.

Bruce

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11 minutes ago, stuglo said:

Nothing convincing

I know it rambled a bit but the answer is in post#22. Also, since then I have had confirmation of the practice. The turning point from tapered to straight planks being the norm is the introduction of (and gradual access to) advances in sawmills. A plank cut by hand using a sawpit does not have to be straight and may as well use the natural taper of the log, whereas a log run through a sawmill will have straight edges as the norm and be much quicker (= cheaper) to produce. So, after a shipyard installs an adequate sawmill, the bulk of the planking will be straight. Some yards mixed the two, perhaps under terms of a contract since change takes time. Of course joggling was still needed and generally followed traditional practice.

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4 hours ago, stuglo said:

After many builds and following many blogs I only recently noticed via superb scratch builds of Le Feuron  ,Bonhomme Richard and Renommee that deck planking in these cases is curved and not parallel joggled. Is this a basic difference between French and English/Dutch?  The decking plan of the Bonhomme Richard (Boudriot) doesn't seem to have a discernible pattern.  Why the national difference? Function? ease of building or national character (?romantic against pragmatic)? 

 

Yes, the curved deck planking seems to be a French thing.  As Bonhomme Richard, Boudriot made an educated guess as he had to reconstruct some from the plans of the original vessel.

 

There's many differences between French and English ships.  Part is wood supply and part was philosophy.  The French had a school set up for ship designers and were willing to try different things.  They hull planking differed from the English also as did their hull designs.  The American frigates hulls seem to inspired by both with the design favoring the French.  I might be wrong on this last point but it just seems that way to me.   

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