Waterways and covering boards for Leon

[Doug McKenzie]

Folks,

 

I have an 1880 DNV classification survey for brigantine Leon and I can't interpret some of it and would love help:

 

Items identified in the survey:

Covering board - 3 1/4" thick x 6 3/4" wide

Outer waterway plank - 7 1/2" thick x 5" wide

Inner waterway plank, 1st plank - 8" thick x 12" wide

Inner waterway plank, 2nd plank - 5" thick x 6" wide

Deck planks - 3" thick x 6" wide

Top timbers - 9" sided x 6 3/4" moulded

 

My thoughts and questions:

What is an outer waterway plank?

I imagine that the Inner waterway plank, 1st plank is a normal waterway.

I imagine that the Inner waterway plank, 2nd plank is a binding strake.  I don't think it can be a margin plank because I think those have to be the same thickness as the deck planking.

The width of the covering board is the same dimension as the top timbers (moulded)- does this mean the 'covering board' is little segments meant to fill the spaces between the top timbers?  How can a normal covering board be this narrow?

No margin plank is mentioned - how do the deck planks terminate?

 

In the absence of additional info, I am probably going to put in a waterway of 5" thick x 18 3/4" wide - 5" thick (not 8") because the waterway will be sitting on top of the deck planks rather than on the deck beams.  18 3/4" wide (not 12") because I'll notch out for the top timbers and let the waterway fill the gaps out to the inside of the bulwark planking.

I'll also install a binding strake of 2" thick x 6" wide - 2" thick (not 5") because the waterway will be sitting on top of the deck planks rather than on the deck beams.

This arrangement seems to me to be the easiest to execute and still give the right overall impression of what this area of the ship might have looked like.

 

I would really appreciate any comments or suggestions on how to model this based on the survey information.

 

Thanks,

 

Doug

[wefalck]

There seem to be many different ways how these planks were arranged.

 

What is strange indeed, is that the covering board is so narrow - the idea of the covering board, notched out for the bulwark stanchions is avoid the difficult to caulk seam along the stanchions. Are your 'top-timbers' really the stanchions ? If not, this may explain the narrow covering board.

 

Otherwise, I could imagine that the 2nd (or 1st, which is wider) inner water-way plank has a sort of quarter-round rabbet planed in, that brings its inner edge to plank thickness, so that it can serve as margin plank. I would think that most of the planks are sitting on the deck-beams and certainly not on the deck-planking.

 

In FRIIS-PEDERSEN's books on Danish ships there are sketches of all sorts of arrangements for these planks on ships from the same period as LEON.

 

I would play around with the cross-sections of the planks to see how the puzzle might fit together.

[Doug McKenzie]

Wefalck,

 

Thanks for the thoughts!  The whole descriptor for top timbers was " Futtock by covering board (top timber)" [This is a location for giving the dimensions of the frame] which doesn't really answer your question but I think according to typical practice this suggests that the top timbers were the stanchions. passing up through the covering board.

 

Your suggestion about the quarter round rabbet allowing the 2nd inner waterway plank to act as a margin plank is creative although the carpentry of intersection would be pretty complex I think because joggling would be necessary and cutting a receiving jog in the 'margin plank' could be very tricky.  And then a valid question would be why introduce the complexity.  Hey, I just had a thought - what if they just don't mention the margin plank that would be inboard of the 2nd inner waterway plank.  The survey might not mention it because it is not a structural timber.  Oh well!  In any event I'm not willing to do the jogging!

 

Your comment about "most of the planks are sitting on the deck-beams and certainly not on the deck-planking" is of course true.  I should have mentioned that the only reason I'm putting the two inner waterway planks on the decking is for simplicity and ease of execution for example the notches for the stanchions are less deep and hence easier to cut and have snug.

 

I tried to find the FRIIS-PEDERSEN books but was not successful either on the internet or amazon.  Any help here?

 

I'm including a drawing of what I think I'm going to do in the spirit of " play around with the cross-sections of the planks to see how the puzzle might fit together."

The covering board is, I'm going to say, sort of being represented by the top surface of the inner waterway plank #1. The Outer waterway plank is being ignored because I haven't the foggiest idea of what it is.  I'd love to hear your thoughts on whether what I'm planning  (shown in the diagram) will have the right 'feel'.

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Posted yesterday at 03:02 AM

 

[wefalck]

These books are rather rare. I chanced onto my copies while trawling antique booksellers in Copenhagen in the late 1990s (when I went there on business quite frequently). The full references are:

 

[FRIIS-PEDERSEN, J.] (1980): Sejlskibe - Danskbyggede traeskibbe opmålt, tegnet og foto-graferet.- Handels- og Søfahrtsmuseets på Kronborg Søhistoriske Skrifter IX: 107 p., København (Høst & Søn).

 

[FRIIS-PEDERSEN, J.] (1981): Sejlskibe - De sidste i Grønlandsfarten opmålt, tegnet og fotograferet.- Handels- og Søfahrtsmuseets på Kronborg Søhistoriske Skrifter X: 108 p., København (Høst & Søn).

 

[FRIIS-PEDERSEN, J.] (1983): Sejlskibe - Nordiske fartøjer opmålt, tegnet og fotograferet.- Handels- og Søfahrtsmuseets på Kronborg Søhistoriske Skrifter XI: 96 p., København (Høst & Søn).

 

They have not been authored by himself, but were issued by the museum in Kronborg Castle (now located outside of it) based on his work.

 

In fact most of the drawings I had in mind only showed the cross-sections of bulwarks, but not actually the constructional details of the waterways and covering boards. Above is a drawing of a single-decked small vessel that shows the covering board sitting atop a plank that in turn sits atop the inner waterway-plank that is sort of hollowed out on the inside.

 

One should perhaps also consider that the measures given in the classification are probably the starting dimensions of the timber. If the top-timbers serve as stanchions as well, they may have been tapered quite a bit (are there dimensions for the rails ?). Also the waterways would have been shaped.

 

I always wondered, how the large quantities of water coming on deck in a storm would be drained with this kind of arrangement. With low waterways and on smaller vessels the lowest bulwark plank often was raise a couple of centimeters or so above the covering board to allow shedding the water. The metal scuppers on the inside of the waterway planks certainly would not be sufficient. Later vessels with metal bulwark plating had freeing ports.

 

There are not many drawings of the deck planks in the above books, but in the few, that are included, there don't seem to be any margin planks and any notching into the waterway-planks either. They just butt against them, even, if that means that they feather out (which would be difficult to caulk). It seems, however, that the deck planks may have been slightly curved to avoid too many planks with feather-edges and to have them instead butting against the well-rounded bow-section and the more square stern-section.

 

The above books are also interesting, because they study the decorative profiling of a lot of planks and timbers. Edges were rounded and decorative beads were cut into the margins of e.g. bulwark planks. This is a feature oven overlooked by modellers, unless they work in really large scales. Dito the edges of stanchions would have been beaded.

Edited November 2, 2019 by wefalck