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Mast Lengths and their above deck heights for HMB Endeavour


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While researching the mast lengths for my HMB Endeavour build I came across an online copy of David Steel's The Elements and Practice of Rigging and Seamanship 1794. Here is the link:

 

http://www.hnsa.org/resources/manuals-documents/age-of-sail/the-elements-and-practice-of-rigging-and-seamanship/page-1/

 

I am finding this to be a great resource even though it is a later compilation from different sources (there are other formulas which varied between shipyard and country during that time) because it has helped answered the tough questions I was having regarding the mast lengths and their respective heights above deck and outboard, which are important to know for the model builder. But to work this out I first needed to know where each mast is stepped. Currently no plan has been found showing the mast steps and below deck stanchion bracings. I finally found the answer in the opening chapter of David Steel's Mast Making Vol.1 which clearly indicates that the fore and main mast's are stepped on the keelson while the mizzen mast is stepped (or more correctly can be) on the lower deck. From this discussion we have located other sources which independently support stepping mizzen masts in the lower deck. The stepping of mizzen standing masts in the lower deck is also supported in William Mountaine 1761 'The Seaman's Vada-mecum and defensive war by sea', and other NMM ship plans prior the 1764 construction of Bark Endeavour.

 

Working back from the 1771 Woolwich Yard mast measurements I found one set of Steel's formula to give me a very close match to these measurements as there are several formulas to choose from but only one set that appears to fit. Remembering that in 1764 ship building was still an evolving art which varied between country's and ship yards while Steel's work didn't come out until 1794, 30 years later. Given this time lag I think it is reasonable for there to be some lee way in interpretation and use of these formulas.

 

With this in mind here is my math:

 

Main Mast (whole length): Wooldwich Yard 69',4".

Formula: L = Length, B = Breadth, L+B/2

To get this to work I've assumed L to be the measurement from stem to stern instead of the gun deck which Steel uses. The gun deck could could have become the standard in 1794 but might not have been in 1764.

 

L @ 109' (approx) + B @ 29',2" divided by 2 = 69' (very close to Woolwich @ 69',4"). Stepped on the keelson @ 20',6" below the quarterdeck. 69',4" - 20',6" = 48',8" height above quarterdeck partners.

 

Foremast: 8/9 of mainmast = 61',6". Woolwich Yard 65',4". Woolwich measurements are in yards @ 21yards, 28inches which would bring the foremast to almost the same height above the waterline as the mainmast and giving it a height of 47',4" above it's partners on the forecastle. (I have since revised this and the foremast looks to be close to within normal ranges at 65'4" compared to the main mast making it's cap around 2.5 feet below that of the main mast cap).

 

Mizzen mast: 3/4 of mainmast = 51',11". Woolwich Yard 50',5". Stepped in the lower deck @ 12',6" below the quarterdeck gives a height of 38' above it's quarterdeck partners making it's cap around 8' below the main mast cap (within so called 'normal ranges')

 

Bowsprit: (whole length) 3/7 of mainmast = 29',8". Woolwich Yard 34'. This does not match until we work out the outboard length which is 3/4 of 29',8" = 22',4". Considering where the bowsprit is stepped in the fore topsail sheet bits then @ 34' it achieves this outboard length of 22',4".

 

The contemporary evidence critically examined in this discussion reasonably and logically supports that the 1771 Woolwich Yard measurements are accurate to within reason. The critical missing peace of the puzzle was that the mizzen might have been stepped in the lower deck and not the keelson as suggest by some late 20th century research. I almost missed this myself until I later searched for it as I realized with out this information I couldn't make sense of the Woolwich yard measurements because stepping the mizzen on the keelson at that length just wasn't meeting up with the angle of the mizzen chainplates from the as fitted draught of 1768. And would make the Mizzen cap 18' feet lower than the Main cap which just isn't the case in contemporary drawings and paintings attributed to Sydney Parkinson from Cook's voyage and nor is it within a so called 'normal range'. Where as stepping the 50'5" Mizzen in the lower deck brings it's cap up by 10' to within this normal range.

 

I apologize for any inaccuracies.

Edited by dashicat
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The mizen mast was stepped on the keelson until late in the 18th century. I suspect Endeavour was stepped in this earlier style. It is irritating that contemporary draughts all omit showing any mast steps!

Thanks Druxey can you provide references for this? If this is the case then how do you explain the evidence of the mizzen chainplate angle on the as fitted draught of 1768 coupled with Steel's reference that the mizzen is stepped in the lower deck which then matchs Steel's formula to the Woolwich mast lengths with the exception of the foremast as I've already outlined and explained?

 

Also Steel does give another set of formulas and in it the mizzen mast length is 6/7 the length of the mainmast = 59',2". The keelson measures 22' below the guarterdeck at the mizzen. So 59',2" - 22 = 37',5" for the mizzen height above the quarterdeck if stepped in the keelson following this formula.

 

Therefore I think this supports my previous calculations for the mizzen above deck height of 38' and the theory that the Endeavour mizzen as fitted 1768 using the Woolwich length was stepped in the lower deck.

Edited by dashicat
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I think Robin's point is that it would be a significant rebuild to the vessel to reinforce the deck to support the mizzen rather than stepping it to the keelson. 

 

I would use the results from Steel with a measure of caution - while it is a good starting point, it was not prescriptive (that is, did not describe how it must be done).  You may want to take a look at Lees, James. 1984. The Masting and Rigging of English Ships of War, 1625-1860. He offers a variety of mesures for different periods, including a table from the 1754 Establishment for various rates.  An additional check may be made of the early Universal Dictionary by Falconer.

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Cheers Wayne. I'm just trying to point out a connection to the Woolwich mast lengths and a formula which supports their measurements and which by chance happens to be Steel's. If you can replicate these figures using another source then be please do.

 

Regarding the stepping of the mizzen mast I am not assuming it was restepped from the hold to the lower deck, but have given reasons for it to be already stepped in the lower deck at the time of the navy's refit. As you point out why go to all that bother when you can use the 6/7 rule and use a replacement mast at 59',2" which still gives approx 38' above the quarterdeck which I did the math for in posts #1 and #3.

 

All I'm interested in answering here are the heights of the masts above their respective decks as my Caldercraft kit scale is inconsistent and needs constant checking. The only reliable source as to these measurents of Endeavour's masts and yards are from the Woolwich Yard. So part of my research into anything would be re miss if I didn't check the Woolwich yard figures where they don't match conventional belief. The results of which I've posted here to share.

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The interesting thing about Steel is that he was neither a mariner nor a ship builder, but rather a lawyer (who once worked in the Admiralty and was fairly well connected) and a book publisher!  It has been a topic of speculation over many years as to who actually wrote some of the materials Steel published.  It was obvious where his Navy Lists came from, but the information on rigging and seamanship, not to mention his Naval Architecture, have been confounding historians for many a year.

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Here is another point to ponder - the following are from The Elements and Practice of Rigging And Seamanship, 1794, by David Steel (online at http://www.hnsa.org/resources/manuals-documents/age-of-sail/the-elements-and-practice-of-rigging-and-seamanship/ )

 

First, a table of masts for Naval vessels of similar tunnage

 

post-18-0-09579500-1464049978_thumb.jpg

 

Now a table for merchant vessels of like tunnage.

 

post-18-0-11798300-1464050008.jpg

 

 

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How do Dash I read you have got your sell all distrest again this time masts and stuff.

 

The Marqwiss of Granbe ,the Marqwis of Rockingham ie Resolution and Adventure were as you must know built at thomas fishberns yard Whitby, both theas ship only a short time after Endevoure both ship had mizin mast stept on keelson, Stell did not have much to dowith merchant ships hope this helpsrobin

Thanks Wayne. I've already seen these and although there is some variation they are very close to the Woolwich measurements with the exception of the foremast which I've I've attempted to answer. Knowing the ratio between the standing mast caps would be a help. But to work this out you would need to know their heights above the water line or know at what height on the keelson each is stepped as I have attempted to do here with the Woolwich measurements.

 

Robin (or anyone who is willing and able) it would help if you could find out the differences between the standing (lower) mast caps for each of the above ships you have mentioned? For example in my figures the main mast is 4',7" taller than the foremost to the water line and 10' taller than the mizzen to the water line. I could be wrong but I would expect to see a relationship of this ratio to other ships of Endeavour's tonnage.

 

Cheers Dashi

Edited by dashicat
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I'm sure that there were exceptions in 1768, Dashicat. However, if you look at contemporary plans, generally you will only see mizen steps on the lower deck from the mid-1780's onward. Check out ships' plans images on the Royal Museums Greenwich web site.

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I'm sure that there were exceptions in 1768, Dashicat. However, if you look at contemporary plans, generally you will only see mizen steps on the lower deck from the mid-1780's onward. Check out ships' plans images on the Royal Museums Greenwich web site.

Cheers Druxey. What you are now agreeing to is that there were exceptions which I have confirmed following your suggestion. Below are some links.

 

To clarify: Why I am assuming or even proposing that the standing mizzen mast was deck stepped as opposed to keel stepped is based primarily on the Woolwich measurements. The mast diameters given by Woolwich. The 3/4 of main mast rule compared with the 6/7 of main mast rule for standing mizzens which give respective approx lengths of 50 and 60 feet and which if the first were lower deck stepped and the second keel stepped have the mizzen cap at approx the same height. The Rigging of Ships: in the Days of the Spritsail Topmast, 1600-1720 page 17 which states that the mizzen was either stepped in the lower deck or the keel and supports my suggestion that there were differing ratios for comparing the respective heights of standing masts on a ship. Keel stepping a 50 foot mizzen wouldn't even come close to any of those ratios so this isn't a reasonable option unless Woolwich has made a mistake as some theories suggest and which I don't have a problem with either if the evidence supports this. The charts that have been provided by Wayne which support a standing mizzen of around 60 feet of comparable vessels (which I would assume to be keel stepped otherwise the spindly mizzen would be as tall as its thicker main mast) and the Cruizer draughts of 1752 which clearly show a deck stepped mizzen.

 

 

 

 

Gallion with mizzen stepped in Orlop deck. https://www.google.co.nz/imgres?imgurl=https%3A%2F%2Fs-media-cache-

 

ak0.pinimg.com%2F736x%2F93%2Fa6%2F42%2F93a6420ea5bfdd3f40eed980e3cdee8b.jpg&imgrefurl=https%3A%2F

 

%2Fwww.pinterest.com%2Fpin%2F279082508131417396%2F&docid=j-yuD_1a6gE3uM&tbnid=96F6k4BW9Mf4oM

 

%3A&w=736&h=603&bih=675&biw=1280&ved=0ahUKEwj2iJbB3PHMAhXCYaYKHdJRCDQ4ZBAzCEwoRzBH&iact=mrc&uact=8

 

 

The Rigging of Ships: in the Days of the Spritsail Topmast, 1600-1720. Page 17

 

 

Cruizer (1752) [alternative spelling: Cruiser] http://collections.rmg.co.uk/collections/objects/84759.html

 

 

 

Robin you are agreeing with Druxey's second statement which is fine. As for gender related remarks, they are not relevant or welcome and if not careful could be easily taken the wrong way and cause offence. Let's leave it at that eh!

Edited by dashicat
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Hi Dashi

I want to weigh in on the argument. To me the main piece of evidence for a taller mizzen is the shrouds and channels. Here is a picture of my AL Endeavour with the shorter mizzen and normal width mizzen channels and the shrouds foul against the quarterdeck rail. The other photo is of the Endeavour I am currently building with the taller mizzen mast and normal channels, the shrouds sit out from the rail like they do for the fore and main mast. To me my Endeavour with a taller mizzen just looks right.

Whilst we are at it, I believe that my AL Endeavour has the correct length bowsprit, the fore stays are at a slightly steeper angle than the main stays like you see on many contemporary models, but not as steep as the fore stays on the replica vessel and as depicted in the AOTS

post-819-0-64701500-1464084298.jpg

post-819-0-06711900-1464084380.jpg

post-819-0-06647300-1464084418.jpg

Edited by shipaholic
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Thank you Steve. Seeing those photos is very helpful and supports the evidence for the taller mizzen. Can you confirm my finding of using the as fitted 1768 draught mizzen chainplate angles to get an approx mast height?

Edited by dashicat
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Hi Dashi

 

I have three draughts of the Endeavour, this one is the "as fitted" one with the longer mizzen chain plates, superimposed over enlarged copies of the AOTS mast drawings. This draught is the one I am using for my build. The other two draughts have shorter mizzen chain plates. Very confusing. If you look at the main chain plates there are huge differences in the angles of the chains. If you extrapolate the "as fitted" draught the main mast would be much taller than proposed in the AOTS, the case is the same on the Earl of Pembroke draught. I can only assume that the Earl of Pembroke's lower masts were taller than the refitted Endeavour's

 

Cheers

Steve

post-819-0-59890200-1464087728.jpg

post-819-0-80604700-1464088394_thumb.jpg

post-819-0-79792300-1464088410_thumb.jpg

post-819-0-08639000-1464088425_thumb.jpg

Edited by shipaholic
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Steve thank you for sharing these draughts. Your top drawing confirms the taller mizzen using the chainplate angles very nicely Steve. Do you have the draught 3814c Robin is mentioning, or come across it showing the mast steps? Yes very confusing and it seems we are working off the same plans marked as fitted. I think my kit is using the intermediate plans with the earlier channels etc.

 

Robin could you put up a link to this draught or post it so we can all see it?

 

Druxey which formula would you like to use?

Edited by dashicat
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Hi Dash

 

I have a draught marked 3814 which is the "as fitted" one

I have a 3814a which is the second one in the above post

The one marked 3814b is the Earl of Pembroke with proposed changes - first one in the previous post

I dont have 3814c - it is the one that many believe to be a much later reproduction

None of the draughts indicate where the mizzen mast was stepped

 

Cheers

Steve

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Cheers Steve. I can't make out any mast steps. Just a series of asterisks marking an imagined line of the mizzen which are non technical so don't really mean a lot.

I also remember reading that draughting linen wasn't used until much later so it's generally not considered an original draught. The AOTS book has the masts stepped on the keelson but also suggests the mizzen could have been stepped on the lower deck.

Thanks Robin.

Edited by dashicat
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Well, for a mizen of 14" diameter, the length should be 60' 0" (naval) or 61' 0" (merchant), according to Steel who is, admittedly a little later than Endeavour. But that give you the 10' 0" differential in length you had mentioned.

Thank you Druxey for taking the time to check my figures and independently confirming the standing height of the mizzen above decks to be around the height of 38'.

 

The foremast: The Woolwich dimensions of the standing foremast are 21 yards and 26 inches or 64',2" with a diameter of 19-3/4". If I have done the math right then this would bring it's top to almost the same level as the main mast which I don't think is correct. If I use the formula of 8/9 of the main mast then it drops it by about 1 yard or 3 feet which is the height I think it should be relative to the main and mizzen standing parts. At this level it also brings the main top mast stays and fore stays into a straighter line running down to the bowsprit. 

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Hi Dash and Robin

 

I have just had a close look at my draughts, both 3814a and 3814b have the asterisks and ticks as you described Robin and show the mizzen stepped in the keelson. But there aren't any visible for the mizzen mast on draught 3814, just for the main and fore masts

 

Cheers

Steve

post-819-0-65375500-1464163115.jpg

post-819-0-82532000-1464163133_thumb.jpg

post-819-0-92465600-1464163160_thumb.jpg

Edited by shipaholic
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Thank you Steve for your perseverance and great detective work. It's really faint and I can hardly make out a mark for the mizzen. In light of this new information this changes my argument regarding the stepping of the mizzen mast and those asterix's, so with my sincerest apologies to Robin I retract my responses to it. In turn I now thank you Robin for bringing this to our attention for critical review.

 

Post script: Just re read Steves post and missed something important in my haste so need to edit and add this. Please correct me if I've got this wrong, but Steve is there still the question of why it isn't marked for the mizzen to the keelson in the 'as fitted' plan 3814 as you point out? Which if so still leaves some room for doubt as to where the mizzen is stepped. Maybe we will never know or wait and see what information they can recover from the wreck?

 

My question regarding the foremast length still remains open to examination.

Edited by dashicat
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Interesting conundrum on the foremast.  Here is the table of masts and yards from ZAZ6594, described as

 

Scale: 96. Plan showing the quarterdeck, upper deck, forecastle, fore & aft falls (a type of platforms), lower deck, and fore & aft platforms for Endeavour (1768), after being re-fitted at Woolwich Dockyard. Signed by William Gray [Master Shipwright, Woolwich Dockyard, 1767-1773].

 

post-18-0-36236000-1464173217.jpg

 

This same plan sheet shows the deck arrangements

 

post-18-0-60379400-1464173253_thumb.jpg

 

(both images may be found at ‘National Maritime Museum, Greenwich, London’, http://collections.rmg.co.uk/collections/objects/86385.html

 

 

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Thank you Wayne for posting this very clear draught. Yes these are the Woolwich measurements that I am reffering to and the deck plan I am working off of for my build. I'd appreciate it if others could double check my math along the way because I can overlook things and make mistakes.

 

Cheers

Edited by dashicat
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Looking at that close-up of the draught, surely there would be reinforcing carlings and pillars under a mizzen stepped on the lower deck? There is no trace of any that I can see.

Thats a fair point Druxey, but to the best of my knowledge the main and foremast steps aren't drawn either so I don't know if we can use that logic. But yes it is still a fair point thanks.

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