Pendant Rope Sizes

[Signet]

I've used the appropriate spreadsheet to determine the proper size of various standing and running rigging on my model, and from that determined the proper size blocks. But I see nothing said concerning the size of the rope used for the block's pendant rope. (I hope I am using the proper terminology.) To illustrate my question, I will post a marked up version of Olha's Carrack rigging, since that is what I'm building:

3 conditions exist:

The pendants outlined in GREEN have two ropes supporting each block, and assuming these are all single blocks, the support an object also supported by 2 ropes. In other words, the pulling force for each rope supporting the block is the same as the pulling force for each rope going through the block. Since the force is the same, I would expect all ropes to be the same size.

The pendants outlined in RED have only a single rope supporting each block. The total force on that rope will be the total force by the 2 ropes going through the block, or twice the force of a single rope. Therefore, I would expect those pendant ropes in red to be larger in size. Going by rope area alone, the larger pendant rope would be 1.41 times the size of the pulley rope, although I have read that larger ropes are proportionally weaker, so 1.5 times the pully rope size seems appropriate. Does that sound correct?

The block and pendant portion outlined in PURPLE supports a single block, which would have 2 ropes going through its pulley, so I would think that this rope would again be about 1.5 times the rope size going through the pulley. The Central block is supported by 2 ropes, so the rope size of its pulley would be the same as the pendant size.

Anyhow, that makes sense to me, but the big question is: Is there a rule or chart to indicate the proper size of single pendants on blocks? What do you do? Does my assumption of 1.5 times the pulley rope size make sense to you?

Oh, and a secondary question I just thought of: Are all such pendants considering Standing rigging, as in most cases the pendant ropes do not go through blocks, and therefore should be black/brown rather than tan? Most, but not all, of Olha's examples are black.

 

[Jack Sparrow]

What spreadsheet are you using, if you don't mind me asking. The one I have does have some rules of thumbs for pendant rope diameter.

 

[Signet]

What spreadsheet are you using, if you don't mind me asking. The one I have does have some rules of thumbs for pendant rope diameter.

First of all, thanks for being the only one to respond to this.

I'm sure I have the same spreadsheet. Yes, it has one size for Pendants (for each sail's running rigging, basically). But I don't think ALL the pendants attached to a sail or its mountings would be the same size, would they? For my model, for example, the Main Course Braces are 0.67mm in diameter, the Sheets 0.71mm and the Clew Lines 0.36mm, and all those have blocks on pendants, but the Pendant size is listed as 0.48. That might be fine for the Clew lines, but it's substantially smaller than the Braces and Sheets, so IMHO that size could never work for them. I have no idea which pendants they are referring to being that size.

My point is that unless the pendants attached to other lines (especially Braces and Sheets, due to their larger size) are at least as strong as the total strength of both Brace or Sheet ropes, then the riggers are wasting their resources by having Braces and Sheets too strong. And they are the longer, i.e. more expensive, portions. It would just make sense to have the pendants attached to the block to be a larger, stronger rope. Again, IMHO.

But I'm new at this, so I certainly could be wrong.

 

[Jack Sparrow]

I am not sure that the physics you used is what the builders used. For example, the rules of thumb below show that the fore and main pendant tackles use the shroud diameter for their circumferences.
Why? I would have thought they would be larger circumference than the shrouds.

 

[Signet]

I'm pretty sure nothing was larger than the Shrouds, except the some of the Stays. My spreadsheet lists the Tackle Pendants as the same size as the Shrouds, which agrees with the above, although my model doesn't seem to have any Main or Fore Tackle Pendants, just Backstays to the topmast.

 

[-Waldemar-]

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Quite a pertinent question. And thankfully a simple answer. It is about the strength of the individual ropes, or in practice their cross-sectional area.

For obtaining/calculating diameters: for a 2-piece tackle, the multiplier or divisor is the square root(2), for a 3-piece tackle – the square root(3), for a 4-piece tackle – the square root(4), and so on.

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[Jack Sparrow]

I'm pretty sure nothing was larger than the Shrouds, except the some of the Stays. My spreadsheet lists the Tackle Pendants as the same size as the Shrouds, which agrees with the above, although my model doesn't seem to have any Main or Fore Tackle Pendants, just Backstays to the topmast.

WIth regards to the main and fore tackle pendants, I think this is related to the period of when the ship was built. But I may be wrong.

 

[Signet]

WIth regards to the main and fore tackle pendants, I think this is related to the period of when the ship was built. But I may be wrong.

I agree. Also, the caption above seems to indicate it is unusual for it to be shown in that way. The purpose of the Tackle Pendant, I believe, is to pull the mast back while tightening the shrouds.

 

[Jack Sparrow]

I agree. Also, the caption above seems to indicate it is unusual for it to be shown in that way. The purpose of the Tackle Pendant, I believe, is to pull the mast back while tightening the shrouds.

that sounds perfectly logical to me.

 

[Signet]

.​

Quite a pertinent question. And thankfully a simple answer. It is about the strength of the individual ropes, or in practice their cross-sectional area.

For obtaining/calculating diameters: for a 2-piece tackle, the multiplier or divisor is the square root(2), for a 3-piece tackle – the square root(3), for a 4-piece tackle – the square root(4), and so on.

.​

I agree completely with your logic, as it is how I feel and stated initially. Although that answer is based on physics and strength, and not necessarily the history or facts of what was done. For example, with Shrouds, the Shroud Lanyards are usually half the diameter of the associated shroud, even though there are 6 lanyard ropes and 1 shroud. Square root of 6 would indicated 40% size for the lanyards, while it would be 50% for 4 lines.

 

[-Waldemar-]

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All this is true. Actually, rigging in the old days is not an exact science and such a general rule should be taken more as a guideline. Other factors are the quality of the ropes, their availability, the different strength of ropes impregnated more or less, the susceptibility to wear or the increased safety reserve in specific applications, etc. Finally, experience and the subjectivity of riggers' judgement, hence so many different historical recipes for rigging thicknesses of the same items. All of this can and should be taken into account, but even so, one will never achieve consistency with all surviving rigging tables or known customs.

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[Jack Sparrow]

At the level of a model, would I call a 0.6 diameter rope or a 0.7 mm diameter rope 1 mm?

 

[WojtasS]

At the level of a model, would I call a 0.6 diameter rope or a 0.7 mm diameter rope 1 mm?

I wouldn't do that. 1mm rope i 1mm. You could do this with 0,6mm and 0,7mm, yes. The differnece between 0,6 and 1 mm is too big. When I was bulding a sailing ship model in 1/200 that difference was visible with bare eye when compered one the other

 

[Jack Sparrow]

I wouldn't do that. 1mm rope i 1mm. You could do this with 0,6mm and 0,7mm, yes. The differnece between 0,6 and 1 mm is too big. When I was bulding a sailing ship model in 1/200 that difference was visible with bare eye when compered one the other

ok. thanks for the information.

 

[Steef66]

Maybe this spreadsheet could help you it is based on old rigging books and are pretty correct to use. The only thing you have to do is knowing the diameter of your mainmast at the base.
The second file is for your blocks. You don't have to use 50 different types of blocks, just your standard blocks that come near the measurement in the sheet.
For example a rope of 0,5 mm. you use a 5 mm. block and for a 0,6 mm. block you use also a 5 mm block

 

[Signet]

At the level of a model, would I call a 0.6 diameter rope or a 0.7 mm diameter rope 1 mm?

What I am doing with my model, before ordering ropes (or blocks, for that matter), is using the tables, spreadsheets and whatever information I can find, determine the EXACT size of the required ropes (and blocks). Once I have a total, I can possibly do some small changes. If I don't have much 0.7mm rope, but a lot of 0.6mm rope, I'll just use all 0.6mm, because you'll never see the difference. OTOH, if I have to get at least 6 yards or so (a full rope skein as sold), I might as well get the exact 0.7mm in addition to the 0.6mm.

A larger model, with a lot of rigging, will often end up with enough for a skein of rope of each size required.

 

[Jack Sparrow]

my difficulty is in quality control. I have started making my own ropes, and I am finding it quite challenging, but fun.

 

[Signet]

Maybe this spreadsheet could help you it is based on old rigging books and are pretty correct to use. The only thing you have to do is knowing the diameter of your mainmast at the base.
The second file is for your blocks. You don't have to use 50 different types of blocks, just your standard blocks that come near the measurement in the sheet.
For example a rope of 0,5 mm. you use a 5 mm. block and for a 0,6 mm. block you use also a 5 mm block

Great information. I like the Mondfeld spreadsheet, as each era has its own sheet, making it easier to read. I'll have to check if the values are the same as I have, but they probably are. The block spreadsheet is very good, giving dimensions for everything, which is good. It uses a different block size to rope size ratio than HiSModel and some other information I've seen though: HiS states block size is 12.5 times rope size, where as the spreadsheet indicates block sizes of 9.35 times rope size.

I don't know why the author of the block size spreadsheet calculated rope size as:
BlockSize = (Dia/10+Dia))*(17/16)*8 --- where Dia = Rope Diameter
when
BlockSize = Dia * 9.35
gives exactly the same value.

But it works too.

 

[Jack Sparrow]

Great information. I like the Mondfeld spreadsheet, as each era has its own sheet, making it easier to read. I'll have to check if the values are the same as I have, but they probably are. The block spreadsheet is very good, giving dimensions for everything, which is good. It uses a different block size to rope size ratio than HiSModel and some other information I've seen though: HiS states block size is 12.5 times rope size, where as the spreadsheet indicates block sizes of 9.35 times rope size.

I don't know why the author of the block size spreadsheet calculated rope size as:
BlockSize = (Dia/10+Dia))*(17/16)*8 --- where Dia = Rope Diameter
when
BlockSize = Dia * 9.35
gives exactly the same value.

But it works too.

yes good point.

 

[Signet]

I did a quick check on the 16th/17th century sizes on the Mondfeld spreadsheet, and found that all size percentages were the same as the HiS spreadsheet, as well as Mondfeld's publication. The HiS spreadsheet calculates the Main Stay diameter as the Mast diameter divided times 0.166, and the Mondfeld spreadsheet calculates it as Mast diameter divided by 6, which is more correct, but that is only a 0.4% error (the HiS sizes are technically 0.4% too large), which is negligible.