MESSIS

How short can the shortest plank be?

I wonder how short can the shortest plank (SP) be. Is there a rule to it? If a ship has average planks of 18 feet*, how short can its SP be? 6 feet? Thats ca. 30% of the avarege plank, that will do or is it rather too small?

 

* of course its a question again how this avarage plank is derminated or better.... how long can an avarage plank be?

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Not in metres or feet - one has to think in terms of where it can/needs to be fastened. I don't think a plank shorter than then distance between three frames (or deck beams) would be feasible due to alingment and caulking problems.

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Thank you wefalck for your help. But please tell me if we speak in terms of bulkheads and not frames would it be correct to say: the shorter plank distance is between 2 bulkheads?

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Wooden ships don't have 'structural' bulkheads. In wooden ships bulkheads are only more or less temporary, relatively light-weight constructions to keep e.g. loads or stores in their place. The idea of bulkheads as structural parts may arise in shipmodellers, as often the model hull is constructed around solid bulkheads - this has nothing to do with a real ship.

 

I think a plank has to cross at least thread (double) frames in order to be properly framed. If it crosses only two frames wave action or the like can push the plank inwards with the ends rising and the caulking falling out. However, such short planks would generally be avoided, if at all possible.

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I should add to the above that the joints between hull-planks would be scarfed, not butted as on the deck. This requires extra length.

 

Below you can see two images of modern-day dhow-building on Zanzibar. Certainly not the most sophisticated builders, but it illustrates nicely how it was done for centuries:

 

Fitting the scarf between two frames:

 

124309-72.jpg

 

The faired and smoothed scarf:

 

124208-72.jpg

 

More details here: http://www.maritima-et-mechanika.org/maritime/tanzania/tanzania.html

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They should probably have a backing plate if the joint is between frames. Which is where I would put the joint. Thre are a lot of different problems to overcome when planking. Wefalcks photos are the proof though.

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Since when are all hull plank joints scarfed? That's not the case, only drop planks and stealers were scarfed as far as I know, rest were butt joints always over frames.

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I gather the question of butt-joints or scarfs depends on how close the frames are spaced and how wide the frames are. If you have double-frames, just a few centimetres apart, you can put a butt-joint just between them without fear that the hull-movement would open the joint or a spike too close to the plank end would split it. If you have wider spaced frames - in my example above they are about 30 to 40 cm apart, you have to make the seam longer and more in line with the run of the planing, i.e. make a scarf, in order to accomodate differential movements of the planks without allowing gaping seams. The scarfs are placed with both ends on frames and no doubling behind is used, at least on Zanzibar. The frames would be too narrow to drive two spikes through next to each other and at a distance that would be safe for the plank ends. Butt-joint would be structurally unsound in this case.

 

It all is a question of the size of the available materials vs. the size of the boat/ship.

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Interesting reading, thanks for the link. This actually opens another front, namely whether we talk about shell-first or frames-first construction, or a hybrid of both. It seems that in fact the latter has been quite wide-spread in Northern European shipbuilding and the dhows of East Africa also belong into this category, as the first few planks are put into place before the inside timbers are errected. Shell-first construction would require horizontal scarfs with backing pieces in order to make a continuous plank. This would typically avoided, if at all possible, for garboard and floor-planks in smaller vessels.

 

However, we slowly deviate from the original question. This should actually be rephrased in the sense that planks were taken as long as available. If shorter ones had to be used, then in areas of the hull of less structural importance, i.e. in general higher up.

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3 hours ago, Backer said:

 

Look at page 25 of this pdf 

http://www.maritimearchaeology.dk/downloads/Full thesis bates.pdf

 

and :

 

Quotes from that page:

 

" Unlike typical carvel vessels, the planking is tightly fitted, with the seams of each plank moulded to fit the adjoining plank..."

"The set work is unique on a carvel vessel of this type, with similar only seen on a shell first barges in Europe (Goodburn, 2009)..."

"The flat vertical scarfs on the outer planking are also unique to frame first construction. They appear in the place of butt joints..."

 

Citing a unique vessel  is not a good example to use.

 

From another thread a couple down from here also about planking lengths, Chuck posted the real planking expansion for his Cheerful cutter:

 

planking.jpg

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4 hours ago, Backer said:

A quick look also answered a long standing question about Wales. The recovered and photographed hull sections show that the Wales were beveled so they could slide off of the wales of another ship, docking structure or whatever they might encounter. Shows me that instincts were right about the edge shape of these important hull protectors. Thanks for the link.

jud

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Indeed, one cannot generalise (easily) from individual ships. However, our physical evidence across the centuries is rather limited, we have to use what we have. Comparing 16th century and early 19th century practices may also be problematic. Production techniques for planks were different, as was timber availability.

 

I didn't read up on CHEERFUL, but where did Chuck get this 'real' planking expansion from ? I gather it is reconstructed ? From which sources ?

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I have to now only focused on English shipbuilding late 16th century (for my Golden Hind).

Even the early 16th century building method looks to be different from this.

 

perhaps there is no general correct answer to this question.

 

What type of ship?
What time period?
which nation?
Maybe even on which shipyard the ship is build?

 

Each time period and country apparently had its own rules and habits.

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Wefalck Chuck used contemporary plans from the NMM site -there are a number available if you search "planking expansion".

 

Rick

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We tend to think too much in terms of (building) rules, regulations and standards - because they have become so prevalent and institutionalised since the early 19th century. We also tend to think that any material could be 'ordered' at any time. However, wood is a natural material with limited supplies of the qualities and dimensions the builders may have wanted. So in practice, they may have had to make do with whatever was available in a particular yard. (Hard)wood supplies tend to follow an annual cycle, with wood being cut during the winter, transported to the rivers for rafting during the high-waters in spring. You couldn't just place an order for a particular kind of timber, when you ran out of it ...

So one should expect a lot of variations dictated by these boundary conditions.

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There are some 17/18th century shipwreck on display in the Netherlands.

The surviving hullplanks inthese wrecks show a large range of variation with respect to framing, planking, dropplanks (just ening in a sharp pointy end),

placement of butt-joints, use of scarf-jounts etcetera. Almost none of these correspond to the existing witten texts on plaking from that era.....

Lesson: shipbuilders tend to be pragmatic, and using their materials as economically as the customer would allow.

It is mainly (English) navy that tended to adhere to strict rule (at least: on paper an din the dockyard models, no idea whether or not that extended to real ships as well.....)

 

Jan

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No-one has mentioned the Mary Rose, launched in 1511 and sunk in 1545.  The remaining starboard side was raised in 1982 and is now on display in Portsmouth Dockyard (UK).  The remains have been well-documented in “Mary Rose: Your Noblest Shippe”, edited by Peter Marsden (2009).

It should be remembered that the Mary Rose was 34 years old when she sank, having spent a hard life in the Western Approaches and taken part in two battles before her final loss, and having undergone numerous repairs.  She can therefore be taken as a fair representation of shipbuilding practices in the early sixteenth century.

The material in Peter Marsden’s book addresses two of the issues discussed in this forum, the type of planking, and typical plank lengths.  Fig 6.17 of the book provides a flattened (projected) view of the surviving starboard side. 

 

MR-planking.jpg.13a31912148c544d114005aaa0482ee7.jpg

 

It shows planks of widely varying widths (and thicknesses) and includes drop planks and stealers.  Planks are typically end-butted (but without any great care to ensure verticality), and the shift of the butts is pretty random.  It also shows the result of several repairs.

 

There is a relevant paragraph in the text, as well:

The length of each plank varies from 1.47m to 10.85m, but most are between 4.5m and 9m long, the longer planks mostly being in the midships area. The shorter planks, those of less than 3m, are low down in the hull at the bow or stern and between the second and third wales (Fig. 6.16b). All the shortest planks, less than 2.75m, are between the gunports.”

The overall impression is that the choice of materials was dictated largely by what came to hand rather than a strict adherence to ‘rule’, but there were clearly substantial lengths of timber available.

 

The message seems to be that, if one is attempting to model a ship of this period, it shouldn't look too tidy.

 

 

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"The message seems to be that, if one is attempting to model a ship of this period, it shouldn't look too tidy."

 

This opens another can of worms ... shoddy workmanship of the modeller vs. representing shoddy workmanship on the prototype. One has to work carefully untidy ... ;)

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On 3/10/2017 at 11:56 AM, wefalck said:

"The message seems to be that, if one is attempting to model a ship of this period, it shouldn't look too tidy."

 

This opens another can of worms ... shoddy workmanship of the modeller vs. representing shoddy workmanship on the prototype. One has to work carefully untidy ... ;)

All shoddiness of any kind on my models will now be labeled as highly-skilled efforts at increased realism.

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Here's a disclaimer from my tech writing days (modified for ship building)....  "All errors and mistakes along with any broken bits whether intentional or accidental are for the sake of realism.   Just deal with it as crap happens."  After re-planking an area on my gundeck for the 5th time (near the bow), I may have have a plaque made and attached to the display. ;)

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On ‎06‎/‎03‎/‎2017 at 3:22 PM, MESSIS said:

Thank you wefalck for your help. But please tell me if we speak in terms of bulkheads and not frames would it be correct to say: the shorter plank distance is between 2 bulkheads?

Agree with Welfalck Frames and Beams are where the Planking or Decking is attached so sencibly THREE frames for planking and three     beams for decking

BUT what about battle damage that would just make the ship seaworthy
Have always tried to get it correct and right but all of a sudden how do you sincibly created Anchor Stocking on any thing less than 1:48th

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