What to do with ledge spacing

[Don Case]

I'm putting the ledges in the midship platform. The space between beams is 1.25". Steel wants 1/4" between ledges so that means 4 ledges.  I'm assuming that asunder means between ledges and not between centers. If I do that the ledge that comes up to the knee hits it at a very long angle. In a situation like this should I just leave out the ledge? It would mean that a portion of the space would be more than 1/4" but it would only be for maybe half the length of the ledge. I've looked around at various builds and it looks like some do just that but it's really hard to tell distances on pictures.

Maybe the knees should have been skinnier.

 

[Don Case]

Maybe this would be better?

[Mark P]

Good Evening Don;

 

Can you confirm your source for the dimension of your carlings. They should be considerably larger in section than the ledges. They look far too flimsy to me. I understand that this is a hold platform, and so may be different, but please check before you make much more. 

 

Some platforms only have beams, to allow the removal of the deck planks to access the hold below. 

 

All the best,

 

Mark P

[allanyed]

Don,

I agree with Mark, the carlings look under sized when compared to the ledges.   If you are using scantlings from Steel, the carlings would be 6 inches broad and the ledges 3.5 inches broad and no less than 9 nor more than 12 inches asunder (yes you are correct that this is the space between them, not C. to C.)  For a lot of detail on how these go in pages 258 and 259 of TFFM volume I shows the solutions that you need.  As well, Goodwin has an excellent drawing of this situation on page 72 in The Construction and Fitting of the English Man of War, including breast riders in place of ledges where necessary.   Goodwin points out on page 74 that the while measurements of the ledges was stipulated (Establishments and contracts I presume) they sometimes varied according to their position.   They are not always the same shape or breadth in the outboard tier.   

Allan

Edited July 4, 2021 by allanyed

[Jaager]

Two parts of this that I recall from my mental database:

The two ledges between deck beams do not butt at 90 degrees. There is a scarph.

The hanging knees do sit below the deck beams. They scarph at the side of the beam.  They are at one side or the other.  Bolts and trunnels hold better and the downward stress is spread over the whole.

I could be remembering this wrong.

 

The original definition of the verb "to scarph"  describes two timbers meeting side by side.   It evolved  and as a noun, it came to describe an in line end to end joinery.

This seems to fit:  verb = side grain to side grain.  noun  end grain to end grain.

[Don Case]

I wondered about the dimensions too, carlings looked way to small. I got them from folio 17 for SOW.  Carlings 4"x3" and ledges 3"x2".The midship platform scantlings appear to be on folio 16, at least the beams are, but I couldn't find carlings and ledges there. I turned the page and found carlings and ledges in the the aft and foreward platform sections. I assumed that if they weren't mentioned earlier that this must be them. As I have said before, I find navigating Steel rather difficult at times.

Funny thing is I had made the decision that I had finished all the parts below the lower deck and glued them all in. The next day I noticed that the platform had no carlings or ledges. Dumbass. So I pried it out and started installing them. Now I find that may not have been necessary. So maybe I can just rip them all out.

Thanks for all the responces

[Don Case]

49 minutes ago, Jaager said:

Two parts of this that I recall from my mental database:

The two ledges between deck beams do not butt at 90 degrees. There is a scarph.

The hanging knees do sit below the deck beams. They scarph at the side of the beam.  They are at one side or the other.  Bolts and trunnels hold better and the downward stress is spread over the whole.

I could be remembering this wrong.

 

The original definition of the verb "to scarph"  describes two timbers meeting side by side.   It evolved  and as a noun, it came to describe an in line end to end joinery.

This seems to fit:  verb = side grain to side grain.  noun  end grain to end grain.

Did you mean the two 'knees' between deck beams? If so the lack of a scarf was just laziness on my part as it will be planked.

 

If I'm following you about the hanging knees, Alan and I had a discussion about this. Apparently these are not 'knees', they are hanging standards so they go under the beam.

[allanyed]

Don,

I double checked folio XL in the Sim Comfort edition of Steel and for the platforms for a sloop of war the scantlings are indeed given for carlings that are four inches broad and ledges that are 3 inches broad.   Keep in mind, Steel was 16 years after Discovery was launched, so may not be apropos.  Then again lacking other contemporary information this is probably reasonable information to use.   Check out contracts on similar sized vessels and they give dimensions of ledges and carlings as well.

 

By the same token if you study a few contracts you will see that they do not conform to Steel in some cases.  One example is the 16 gun sloop of war Echo, 1782.

The following is the description of the platforms and lower deck from the contract of Echo:

PLATFORMS     ......................  beams sided 6½  inches and moulded 5½

                                       to be kneed if directed,  to be provided with Carlings and Ledges same as the Lower Deck.................

 

LOWER DECK CARLINGS AND LEDGES      ....................the Carlings to be 7 inches broad, and 6½ inches deep................................ The ledges to be of Oak 4 inches broad, and 3½ inches deep, to be spaced not more the 12 inches, nor less than 9 inches asunder.

 

Do look at the ledges and breast riders in Goodwin's and Antscherl's books.  Some look nothing like the majority of ledges which are rectangular in shape when seen from above and there are no places where any ledges lie in such a way that they  would appear to be nearly side by side with the athwartships arms of the lodging knees.   

 

Hope this helps.

 

Allan

Edited July 5, 2021 by allanyed

[allanyed]

Don,

I double checked folio XL in the Sim Comfort book on Steel and for the platforms for a sloop of war the scantlings are indeed given for carlings that are four inches broad and ledges that are 3 inches broad.   Keep in mind, Steel was 16 years after Discovery was launched, so may not be apropos.  Then again lacking other contemporary information this is probably reasonable information to use.   Check out contracts on similar sized vessels and they give dimensions of ledges and carlings as well.

 

By the same token if you study a few contracts you will see that they do not conform to Steel in some cases.  One example is the 16 gun sloop of war Echo, 1782.

The following is an example of  the description of a platform and lower deck from the contract of Echo:

AFT PLATFORM     ......................  beams sided 6½  inches and moulded 5½

                                       to be kneed if directed,  to be provided with Carlings and Ledges same as the Lower Deck.................

 

LOWER DECK CARLINGS AND LEDGES      ....................the Carlings to be 7 inches broad, and 6½ inches deep................................ The ledges to be of Oak 4 inches broad, and 3½ inches deep, to be spaced not more the 12 inches, nor less than 9 inches asunder.

 

Do look at the ledges and breast riders in Goodwin's and Antscherl's books.  Some look nothing like the majority of ledges which are rectangular in shape when seen from above and there are no places where any ledges lie in such a way that they  would appear to be attached nearly side by side with the athwartships arms of the lodging knees.   

 

Hope this helps.

 

Allan

Edited July 5, 2021 by allanyed

[Don Case]

The hard thing is that a SOW doesn't show anything for a midship platform so I assumed that they didn't have one. On folio 19 a midship platform is only shown for frigates. So I just used the smallest for the beams if I remember right. The carling/ledge scantlings I got(the 4 and 3 inch ones) I'm assuming are for the aft and forward platforms. These are a lot narrower than the midship platform so I would expect the scantlings to be smaller. it is going to be planked and no one will ever see them so it's a moot point really. It's just for my own interest.

 

I can't spend the farm on books so I guess I'll just build it as I think it should be and then correct it when you guys tell me it's wrong.😃

Thanks

[allanyed]

Good morning Don,  

Maybe ask Santa, Christmas is not too far away.   Used copies of Goodwin can be had for $40 on Amazon these days.  BTW, what is SOW?  I am familiar with The Shipbuilder's Repository, Steel's Elements and Practice  of Naval Architecture and Scantlings of the Royal Navy, but not SOW.      

Allan

[Don Case]

Sloop of war, I just got tired of typing🙂

 

I was just re-reading this thread and you give some scantlings for the "Echo". If I'm reading it right and you use the lower deck carlings and ledges you end up with the carlings being bigger than the beams. That doesn't make any sense to me.

Is there any place on line that I can look at any contracts. I tried the NMM and I can see where they have them but being 20-24 pages they don't show any part of them.

[allanyed]

The National Archives in Kew.    There are copies of contracts in a number of books as well, including Goodwin et al, but again, there is a cost involved.  Unfortunately, not everything we need to use in our never ending research is free.     Wish that was not the case, but..........

Allan

[allanyed]

Just ran across a deck drawing for a 1745 Establishment ship that is incredibly detailed, much more than most contemporary drawings in that it shows every ledge as well as carlings and beams and much more.  It is for a 60 gun ship, but the information is likely applicable to other sizes in that era.    Caruana showed it in Volume II of English Sa Ordinance and credited RMG.  I went to the RMG collections and found the drawing there so it is available in low resolution for free, but I am thinking I may have to go for a high res copy for future use.   

https://collections.rmg.co.uk/collections/objects/81698.html     Caruana notes that this may be the Weymouth on which Murray Mungo served as a carpenter. 

 

I saw that you are checking in here at MSW Don, so I hope you see this and that it helps you.

 

Cheers

 

Allan

Edited August 11, 2021 by allanyed

[Mark P]

Good Evening Allan;

 

Thanks for posting this, I have not seen one with such detail before either. There are some quite detailed draughts of Dorsetshire of 1757, and Hampton Court of 1709, which show all the beams, knees and carlings, as well as much deck detail; but they don't show ledges. So many thanks for pointing this out.

 

All the best,

 

Mark P

[Mark P]

Good Evening Allan;

 

Following on from your lead, I have searched through the RMG collections, and there are two similar sheets of plans for the St George of 1740 (although the plans have the date 1742) She was a three decker, and I believe that there is a model of her in either the Kriegstein or Annapolis collections.

 

All the best,

 

Mark P

[druxey]

I love the double beam arm arrangement at the main mast on that draught!

[allanyed]

Mark,

Found it,  THANKS.  

Three decker,,,,,  hmmmmm, not sure I want to tackle that kind of project at any scale.  Then again.......  Ah well,  if I was 40 years younger with more time left than has gone by, maybe......