Calculating mast size (and possibly location)

sketty

sketty

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Hello, I'm curious about how, as a scratch builder especially, you can know the size for your masts.

I've heard of a formula for calculating the height (possibly diameter too) of masts based on taking the beam of a vessel and doing some calculations but I don't think I've saved it. Is anyone aware of such a thing? The ships I plan on building from scratch are mostly 17th century english ships, so I'm not sure if the formula would even fit, as I remember it being used for 17th century dutch builds.

Any help is appreciated.
 
Before I forget, as mentioned in the name of this post, I'm fairly certain I heard of a formula for locating the masts aboard a ship (that is; full-rigged, 3 masted). So info about this would be similarly helpful.
 
sketty said:
I've heard of a formula for calculating the height (possibly diameter too) of masts based on taking the beam of a vessel and doing some calculations but I don't think I've saved it.
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For English ships it depends on the era. James Lees gives formulas for various eras from 1625-1860. Some are a little complex, others straight forward. Some deal with keel length and beam others with gundeck length and beam. All dimensions for masts, yards, standing rigging and running rigging begin are based on the length of the main mast. To get the main mast length from 1627 it's the beam X 2.4---- From 1670 add together the length of the keel, breadth of the ship and depth of the ship then divide by 1.66. If the beam is more than 27 feet deduct the excess from 27 from the total. If the beam is less than 27 feet add the shortage. For example if the beam is 32 feet add 5 feet to the total.----- From 1711 to 1719 to get the length of the main mast add the length of the lower gun deck and the extreme breadth and divide by 2. ---- The formula changes again in 1719, 1745 and 1773.

Once you have the length of the main mast you can calculate the lengths of the other lower and upper masts as well proportionate dimensions of the diameters of the masts at the partners.

Allan
 
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Hi Allan, that's exactly what I was looking for. Thanks a lot for the help, it'll be very helpful for my scratch builds.

Y.T. , that's not exactly what I was looking for though I believe I can still get use out of it - even if it's just for the fun of learning it - so thank you, too.
 
"AllanKP69," above, is too modest. I hope he won't be upset that I blew his cover. In fact, Allan is the author of the "Bible" on this subject: Scantlings of The Royal Navy 1719-1805: Comparisons of 1719, 1745 Establishments, Ship Builders Repository and Steel’s Elements and Practice by Allan Yedlinsky, Published by SeaWatchBooks, LLC. 2014. ISBN-13: 978-0-9837532-9-2

See: https://seawatchbooks.com/products/...el-s-elements-and-practice-by-allan-yedlinsky

Over 200 pages of the book are tables of British Naval ship scantlings and dimensions, including:

A.) 1719 and 1745 Establishments and the 1750 modifications to the 1745 Establishment.
B.) 1788 Shipbuilder's Repository and Steel's Elements and Practices of Naval Architecture scantlings for ships from 110 guns down to 10 gun brigantine. Merchant vessel scantlings were not included because there just was not enough room.
C.) Boat scantlings from Steel
D.) Anchor scantlings from Steel
E.) Drawings showing many of the items listed in the scantlings.

The work is presented in a lay flat binding so that when opened, 28” of spreadsheet formated information is in front of the reader.

**********************************************************************************************************************************************************
From the publisher's review:

This specially formatted book (14”x8 ½”) is divided into 2 sections. The first shows all of the scantlings from the 1719, 1745 and 1750 amended figures in an easy to use spread sheet format.

The second section compares Steel and Ship Builders Repository in the same format. Additionally, the author provides notes and comments for each section. The work is presented in a lay flat binding so that when opened, 28” of information is in front of the reader.

In the preface to the 1755 edition of Sutherland’s Ship-Builder’s Assistant, the anonymous editor offers the following:

The advantages flowing from Shipping, are so great and conspicuous, especially to the Inhabitants of these Kingdoms, that it would be superfluous to advance Argument in Favour of the Art of SHIP-BUILDING, or MARINE ARCHITECTURE, and therefore whatever has the least tendency to its Advancement, certainly merits Encouragement. It should also be remembered that every Improvement made in an Art of such Importance to Society, adds a farther Security to the Power, Strength, and Interest of these Kingdoms.

Allan Yedlinsky provides the model ship builder, as well as the naval historian, with a valuable contribution to the art in his Scantlings of The Royal Navy 1719-1805. The builder of a model ship, not unlike the builder of the full-size ancestor, requires a great deal of information to build a model which accurately represents the desired vessel. While the basic dimensions of length, beam and number of guns is important, these alone fail to provide sufficient information to describe the intricacies of the vessel. To fully describe the desired result necessitates the use of a 3-dimensional description of not just the summary dimensions, but the sizes (or scantlings) for a myriad of smaller bits and pieces.

In Scantlings, Yedlinsky brings together the detailed information from the primary sources of the era used to guide the building of His Majesty’s ships of war during the 18th and early 19th centuries. While other books have been published on the topic (such as Goodwin’s The construction and fitting of the English man of war, 1650-1850), none have to date pulled the detailed scantlings together in one easy to use set of tables. In Scantlings, we have for the first time all of the gritty details from the early Establishments, which were intended to standardize the construction of British war ships (actually, with humble apologies to Captain Barbossa, in practice they became “…more what you'd call "guidelines" than actual rules.”) The detailed tables of scantlings are both extensive and legible, set in a spacing and font which is easy to see without visual aids. The inclusion of the un-official (but more generally known) information from the Shipbuilders Respository and Steel’s Elements and Practice of Naval Architecture serve to extend the period covered through the Napoleonic wars and nearly to the advent of steam.

No endeavor this ambitious could be expected to include every potential source of information. Yedlinsky has selected a set of valuable reference documents that are not only comprehensive in their own right, but perhaps more important, when consolidated in such a manner they offer an interesting insight into 100 years of evolution in shipbuilding. When used with care, heeding the advice offered by Yedlinsky, these scantlings can aid the model maker in filling in the gaps between plans, paintings, logs and other contemporary sources to build an historically accurate model.

As noted in the preface from Sutherland , It should also be remembered that every Improvement made in an Art of such Importance to Society, adds a farther Security to the Power, Strength, and Interest of these Kingdoms.

Yedlinsky has quite effectively consolidated some of the most important information concerning the improvement in the art of shipbuilding into this very useful volume. Whether a novice or a journeyman, if you are intending to build a British man-of-war from the 1700’s into the early 1800’s, this volume deserves a place on your bookshelf, along with your other most frequently used reference books.
*******************************************************************************************************************************************************
Many may already have a reprint copy of Steel's and other primary reference works, or have access to them on the web, but Allan's reorganization of the material into readable form makes the "price of admission" well worth it. The print in the originals is often so small as to be virtually unreadable and their archaic type faces and spelling create further confusion and uncertainty. Allan's compendium presents the tables in easily readable useable form for modelers. With a copy of this manual in your library, you'll never again be asking the proper size of any part of a British Admiralty vessel of the period 1719 to 1805 and, by extrapolation, should be able to estimate the often slightly lighter scantlings for merchant ships of the same period as well as naval practice through about 1850. The many period illustrations, again in a readable size, will be found invaluable by any modeler building Admiralty vessels of the designated periods.

This volume is a valuable resource for any builder of Admiralty period model kits. It is an essential resource for any scratch builder of them.
 
Bob Cleek said:
The print in the originals is often so small as to be virtually unreadable and their archaic type faces and spelling create further confusion and uncertainty.
Click to expand...
Thanks Bob, I do appreciate your comments very much. The reason I did the project was not so much the fact that many things were hard to find and read, it was more that the price for a copy of The Elements and Practice of Naval Architecture, The Shipbuilder's Repository (anon) and high resolution copies of the Establishments from RMG would be close to US$1,500 which few people want to spend. I got lucky and purchased Steel and The SR from NRG for less than $200 when they sold off their library. The books of course contain a LOT more information than scantlings but it seems the most common use for those that had them was to get the scantlings. I wish there was some sort of compendium for this kind of information prior to the Establishments but I have yet to find this. So, for now I have to rely on contracts if they can be found and the drawings I would use. Even if a project is for a vessel within the dates covered by the book it is still a good idea to try to find contemporary contracts and as-built drawings to confirm or correct dimensions on any given ship.

Thanks again for your truly kind post Bob.

Allan
 
sketty said:
Hi Allan, that's exactly what I was looking for. Thanks a lot for the help, it'll be very helpful for my scratch builds.
Click to expand...
Glad to help Sketty. The length of the masts is only the beginning. I strongly recommend getting a copy of Lee's Masting and Rigging of English Ships of War as the ratios are there for calculating all mast, spar, and rigging dimensions. He even gives ratios from the rigging sizes to block sizes as well as types of blocks and other hardware used in rigging. Both scratch and kit builders have benefited greatly from this book.

Allan
 
AllanKP69 said:
For English ships it depends on the era. James Lees gives formulas for various eras from 1625-1860. Some are a little complex, others straight forward. Some deal with keel length and beam others with gundeck length and beam. All dimensions for masts, yards, standing rigging and running rigging begin are based on the length of the main mast. To get the main mast length from 1627 it's the beam X 2.4---- From 1670 add together the length of the keel, breadth of the ship and depth of the ship then divide by 1.66. If the beam is more than 27 feet deduct the excess from 27 from the total. If the beam is less than 27 feet add the shortage. For example if the beam is 32 feet add 5 feet to the total.----- From 1711 to 1719 to get the length of the main mast add the length of the lower gun deck and the extreme breadth and divide by 2. ---- The formula changes again in 1719, 1745 and 1773.

Once you have the length of the main mast you can calculate the lengths of the other lower and upper masts as well proportionate dimensions of the diameters of the masts at the partners.

Allan
Click to expand...
Hi Allan
What science were these measurements based upon ? I assume that the formulas were not derived from (?) have hydrodynamic tests, or wind-tunnels...Were they derived from practical experience with measuring a "good sailer", comparison with other (French) ships, or from experimentation?
 
Alex R said:
What science were these measurements based upon ?
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Sorry Alex, I have no idea. It is my understanding Lees developed his formulas, which are now very well accepted, based on contemporary sources including masting and proportionate tables, manuscripts, drawings, and other sources. Unlike hull scantlings, there are few, if any, heavily detailed spread sheets such as those from the 1719-1750 Establishments, The Shipbuilder's Repository (anon) or David Steel's Elements and Practice of Naval Architecture. Steel did prepare a detailed 1794 treatise, with drawings for masting, rigging, and seamanship in the late 18th century as well, but it is not very useful for mid 18th century or earlier time periods. Anderson wrote his book, The Rigging of Ships in the Days of the Spritsail Topmast 1600-1720 after much research into works such as the writings of Keltridge and the Treatise on Rigging written about 1625 and printed the first time in 1925 by The Society for Nautical Research. And the list goes on.
Allan
 
Hi Alex;

The proportions were based on long experience of what worked. There are various sources for calculating mast lengths, going back at least as far as Mathew Baker. Diameters are rarely given, though, and it would seem that either the method of calculating diameters was well-known, or that people had their own formulae.

The Treatise on rigging which Allan mentions is very useful, but unfortunately it only describes the main mast and mizen. It makes no mention of the rigging of the foremast or bowsprit.

Ratty
 
Bilge Ratt said:
The Treatise on rigging which Allan mentions is very useful, but unfortunately it only describes the main mast and mizen. It makes no mention of the rigging of the foremast or bowsprit.
Click to expand...
Hi Ratty
The Steel treatise gives information for the lengths and diameters of the sprit, foremast, main mast, and mizen on page 39. Keep in mind this is for circa 1794 so useless for the 17th century, Sketty's area of interest. As to rigging, Steel gives details on where every line goes for all the masts and yards starting on about page 194 to 237. He does not give the circumferences of the lines in the copy I have, but maybe some member knows if Steel provided these as well. For the 17th century from 1625, all the dimensions, including circumference of the lines, the best source I can find is Lees' book.
Allan

The following is from the San Francisco Maritime National Park copy
THE FOLLOWING PROPORTIONS FOR THE HEIGHTH OF MASTS ARE THOSE BY WHICH SHIPS AT PRESENT ARE MASTED IN THE ROYAL NAVY.​
The length of the lower deck and extreme breadth being added together, the half is the length of the main-mast.
The length of the lower deck of a 74 gun ship is 176 feet. Breadth extreme 48 feet 8 inches; added together, they make 224 feet 8 inches; the half, or 112 feet 4 inches, is the length of the main-mast; which being determined, the other masts, yards, &c. bear the following proportions.
​
Fore-mast, 8/9 of the main-mast.
Mizen-mast, 6/7 of the main-mast.
In Sloops, the mizen-mast, 3/4 of the main-mast.
Main-topmast, 3/5 of the main-mast.
Fore-topmast, 8/9 of the main-topmast.
Mizen-topmast, 3/4 of the main-top-mast		Sloops mizen-topmast, 5/7 of the main-topmast.
Topgallant-mast, 1/2 the length of the topmast.
Bowsprits of 80 guns and upwards, 7/11 of the main-masts.
Bowsprits of 74 gun ships and under, 3/5 of their main-masts.

​
The diameters in proportion to the length, in the royal navy, are as follow: viz.
The main and foremasts of ships of 100 to 64 guns inclusive, are one inch in diameter at the partners to every yard in length. Ships of 50 to 32 guns inclusive, 9/10 of an inch to every yard in length. And ships of 28 guns and under, 7/8 a of an inch to every yard in the length.
The main-mast of brigs to be one inch to every yard in length, and the foremast 9/10 of the diameter of the main-mast.
Masts of cutters to be 3/4 of an inch in diameter to every yard in length.
The mizen-masts of ships of 100 to 64 guns, inclusive, 3/5 of the diameter of the main-mast; 50 gun ships and under, 2/3 of the diameter of the main-mast.
Diameter of the main and fore topmasts, one inch to every yard in the length of the fore topmast.
Diameter of the mizen-topmast, 7/10 of the diameter of the main-topmast.
Diameter of the topgallant-masts, one inch to every yard in their lengths.
Diameter of the royal-masts, 2/3 of the diameter of their topgallant-masts.
Bow sprits of ships of 100 to 64 guns, inclusive, two inches less than the diameter of the main-mast. In 50 gun ships and under, the same diameter as the main-mast.
In the merchant-service the proportion of masts and yards are variable; therefore Tables of Dimensions for vessels of different tonnages are subjoined.
 
Hi Allan;

My apologies; I think that maybe I was not quite clear enough; the treatise I was referring to, which you mention, was the last one, the one which Anderson published; this is close in time to the period which Sketty is looking for; but unfortunately, it is not complete in its coverage. I have seen the original of this, and although there might once have been additional pages covering the missing areas, I am not sure; it is not obvious that any pages are missing. Lees' book is certainly the best published reference source for the second quarter of the 17th century, but how far back he can be taken is not something which I have yet looked into.

There are several lists of mast sizes from the late Elizabethan early Jacobean period; but these do not always include the yards, and never the diameter. Sir Henry Manwayring's dictionary gives some guidance on the proportions to use, but as he wrote around 1625 (Smith's Sea Grammar is a shameless plagiarisation of Manwayring's work) the proportions are probably those used by Lees.

Ratty
 
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