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A question about beveling frames


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I finally have the Leavitt plans for the Charles Davis Lexington ( so-called ) armed brig, and am puzzled by his frame station layout and his frame plans. See photos.

 

The frames are to be made up with futtocks in the usual manner. What puzzles me is that as you can see, he clearly shows the frames centered on the station lines. I was taught that the frame positions forward of the midship section should be placed forward of the frame station, and aft of the midship station the frames should be placed aft of the frame station, all to allow for the bevels.

 

Then I look at the frame plans, and have not a clue as to why, in certain frames, there are futtocks that project beyond the fair curve of the frame face. Also, there are black shaded areas, some on the outside, some on the inside, but never both. Am I to deduce these are the bevels? Are not the frames beveled inside and outside? What are the multiple of lines showed on each frame? I was expecting something not so rigorous, and being a newbie could use some guidance from the forum. Thanks. 

Lexington frame stations.jpg

Lexington frames.jpg

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Good Morning Gerard;

 

The frames are centred on the station lines because this is the joint line between two separate frames which make a sandwich, with the joints in each slice of the sandwich being staggered.

 

The shaded area would seem to be the edge of that part of the frame which lies on one side of the joint line, and the un-shaded area is the edge of the other half of the frame.

 

For example, in frame 5, the shaded portion each side is a single, un-jointed piece of timber, whereas the un-shaded part of the frame is in two pieces each side, and lies behind the shaded part. The joint line is shown dashed because it is hidden. Both halves of the sandwich have an almost equal amount of bevel. It also appears that one half of the sandwich stops at a lower height than the other, presumably around deck beam level.

 

All the best,

 

Mark P

Previously built models (long ago, aged 18-25ish) POB construction. 32 gun frigate, scratch-built sailing model, Underhill plans.

2 masted topsail schooner, Underhill plans.

 

Started at around that time, but unfinished: 74 gun ship 'Bellona' NMM plans. POB 

 

On the drawing board: POF model of Royal Caroline 1749, part-planked with interior details. My own plans, based on Admiralty draughts and archival research.

 

Always on the go: Research into Royal Navy sailing warship design, construction and use, from Tudor times to 1790. 

 

Member of NRG, SNR, NRS, SMS

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Good Morning Gerard;

 

If you mean the projections at the bottom, the heel, this is due to the frames not being square to the line of the keel, but canted forward, so the heel has to be angled to fit against the side of the keel.

 

If you mean the projections at the sides, this is simply because one half of the frame, the aft portion, one half of the frame sandwich, is much wider than the forward part of the frame, the other part of the sandwich. This is due to the taper of the ship towards the bow. Canting the frames negates some of the taper, but not all of it.

 

All the best,

 

Mark P

Previously built models (long ago, aged 18-25ish) POB construction. 32 gun frigate, scratch-built sailing model, Underhill plans.

2 masted topsail schooner, Underhill plans.

 

Started at around that time, but unfinished: 74 gun ship 'Bellona' NMM plans. POB 

 

On the drawing board: POF model of Royal Caroline 1749, part-planked with interior details. My own plans, based on Admiralty draughts and archival research.

 

Always on the go: Research into Royal Navy sailing warship design, construction and use, from Tudor times to 1790. 

 

Member of NRG, SNR, NRS, SMS

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  • 2 weeks later...

Mark, thanks again, yet still I am as thick as a brick. The projections I was referring to were the ones on the inside or outside of the frames indicating the deck beam level. Charles Davis, in his book The Built Up Ship Model, talks about built-up framing from pages 21-24. The photo herein is from page 21, and clearly shows the projections, but that is because he drew the frame in perspective, no? 

 

In other words, am I to assume that the futtocks are all the same molded size for what I will call layer 1 and layer 2 ( both layers, of course, comprising the frame itself ), or am I to cut the futtocks out so that one layer is wider than the other to account for bevel? 

 

It seems to me that if the frames were simply futtocks of all the same size for each layer, and placed so that the forward frames were positioned forward of the stations and the aft frames placed aft of the stations, life would be simpler. Aaargh. Davis talks about this, how " the shape of the frame...is the middle of the frame, the seam where the two pieces come together ".  He then talks about how one layer is cut on a standing bevel, and the other on an under bevel. Sure, OK, but. Again, aargh. How can the seam line be aligned with the station line of the hull, when the standing bevel layer would need to be larger to accommodate the bevel? 

 

I hate the feeling that I am not as smart as I thought I was. 

Davis frame.jpg

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OK,  some definitions - 

a FRAME -  floor + 2nd futtock + 4th futtock/top/half top (depending)  

also a FRAME  1st futtock + 3rd futtock + top/half top

a BEND   is both of the frames when joined together as a unit  -  the overlap at each butt makes the unit a strong one.

 

French and North Americans  generally framed using all bends.   The English ( or at least their navy ) often used a wider spacing of bends and had free standing frames (filling frames) in the gap between.

(Butt joints are weak and in a model a free standing frame tends to be fragile.  This makes RN framing a bit of a PITA for POF.)

 

The Body plan is the stations in a stack.   The stations define the mid line of the bend at its location.  All stations define the mid line of a bend.  But, not all bends have a defined mid line on the plan.  It varies with the ship and where along the profile the station is.  It might be every 4th or every 3rd or every other.  I have USN corvettes with 8 bends between stations in the mid ship zone.

 

The confusion you seem to have with bevels and station lines may be because you are thinking the stations are useful for standard POF methods.   They are not.  Except as a check on your curve plotting and as a short cut on every other to every 4th bend, they are useless.  Each bend must be lofted.  If you glue up the stock for each bend 1st,  only the fore and aft shape for each bend  (Hahn).   If you assemble the isolated frame timbers into a bend,  the mid line of each bend also needs lofting.   There are maybe 40 bends in a Cruizer,  so it is 80 or 120 lines that need plotting to loft the framing.

 

The plans for Lexington are actually those of an RN Cruizer brig.  A different era and a different country, 

 

When Davis writes about under bevels, I am not sure that he understood why it was significant.  It was a significant factor in the way ships were framed before 1860.  But Davis was schooled in the methods that were used around 1900 and  at that time much more was done in the mold loft than was done in the earlier era.

 

If you want to see a method where the station lines are important - vital even - check out my log for La Renommee.  I have not presented how to do the lofting or do true POF yet - (how to use easy release bonding and temporary fillers for the spaces, but you may be able to intuit how).

 

One other thing, the floors that Davis is presenting are very short.  The ABS specifies that floors should be 60% of the beam.  What Davis is showing is closer to the length of a half floor which would be in the frame with the 1st futtocks.  Rather than butt at the keel,  the 1st futtocks would butt the half floor.   This was more common in French and North American ships,  but the RN often used a short version termed a butt chock over the keel. 

 

NRG member 45 years

 

Current:  

HMS Centurion 1732 - 60-gun 4th rate - Navall Timber framing

HMS Beagle 1831 refiit  10-gun brig with a small mizzen - Navall (ish) Timber framing

The U.S. Ex. Ex. 1838-1842
Flying Fish 1838  pilot schooner -  framed - ready for stern timbers
Porpose II  1836  brigantine/brig - framed - ready for hawse and stern timbers
Vincennes  1825  Sloop-of-War  -  timbers assembled, need shaping
Peacock  1828  Sloop-of -War  -  timbers ready for assembly
Sea Gull  1838  pilot schooner -  timbers ready for assembly
Relief  1835  ship - timbers ready for assembly

Other

Portsmouth  1843  Sloop-of-War  -  timbers ready for assembly
Le Commerce de Marseilles  1788   118 cannons - framed

La Renommee 1744 Frigate - framed - ready for hawse and stern timbers

 

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I learn something new almost every time I come here. I have never heard the term' bend ' used at all regarding frames in any of the books I have read, so thank you Jaager. I will check out your build log for La Renommee.

 

Meanwhile, Leavitt DID loft all 37 bends so I don't have to, and I show some of them in my first post. 

 

Still unanswered for me is why the Leavitt bend/frame/futtocks are not drawn in fair curves i.e. why the projection at the deck beam level. At this point I have half a mind to simply make bends fair, place them at all 37 stations the way I was taught in boat school, bevel away accordingly, and let the devil take the hindmost.  I hate to admit defeat, though. 

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Gerard,

 

Not having the Leavitt plans,  I will interpret what I see in your pix.

It is all bends.

The space is equal to the width of a frame. i.e. 2/3 room  1/3 space.  This is very common for Antebellum American ships but not so much for the end of the Colonial period.  As far as I know, not much is known about about smaller vessels, but for frigates on up, it was almost all room.  The space was about 1 inch.  This was a 10-20 year span - things evolved post Revolution.  Perhaps the folks at TA&M will find something someday.

 

The bends -  #5

The gap at the keel is unique to me. No floors, it is as though it is intended that there be deadwood above the keel along the entire length and half bends butt against it.  Not the strongest method that I have seen.

The outside line is outer face of frame closest to the mid ship station (the dead flat - because there is no bevel on it).

It goes up to the underside of the rail.

The next line is the bevel of that frame and the mid ship face of the next bend.

BUT, that frame ends at the deck level.

The black line is the bevel of aft side frame.  ( I am guessing that the convention of letters for fore bends and numbers for aft bends is being followed.)

It is black to make it easier to follow.

The next 3 lines are the inside shapes of the molded dimension.  The aft frame ends at the deck level.

I think it is intended that there be a single stanchion (top) at every bend.

 

You may trust Leavitt,  but in your place I would scan the frame patterns,  open them in a drawing program ( Painter for me),  adjust for the scanner scaling aberration,  scale to my preferred scale,  select the right side and horizontally flip it and use that for the left side. (instead of trusting that Leavitt was able to draw the let side to be identical to the right.)  But I would also mate the two sides at the center line and define the floor and make whole bends.

 

I am not sure about Continental brig sized vessels, but most warships seem to have planking covering the inside of the tops. (A feeble attempt at amour?)

With POF, I am enamored with curves and framing of the swimming body.  The area above the main wale/LWL not so much.  It looks more like house carpenter framing - mundane and boring. It only needs to be functional and is almost never elegant.  I cover it with planking.  Because I cover it and it makes for a stronger hull, I make my framing above the LWL solid - including the spaces.

 

NRG member 45 years

 

Current:  

HMS Centurion 1732 - 60-gun 4th rate - Navall Timber framing

HMS Beagle 1831 refiit  10-gun brig with a small mizzen - Navall (ish) Timber framing

The U.S. Ex. Ex. 1838-1842
Flying Fish 1838  pilot schooner -  framed - ready for stern timbers
Porpose II  1836  brigantine/brig - framed - ready for hawse and stern timbers
Vincennes  1825  Sloop-of-War  -  timbers assembled, need shaping
Peacock  1828  Sloop-of -War  -  timbers ready for assembly
Sea Gull  1838  pilot schooner -  timbers ready for assembly
Relief  1835  ship - timbers ready for assembly

Other

Portsmouth  1843  Sloop-of-War  -  timbers ready for assembly
Le Commerce de Marseilles  1788   118 cannons - framed

La Renommee 1744 Frigate - framed - ready for hawse and stern timbers

 

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  • 1 year later...

Charles Davis got his wooden shipbuilding experience in shipyards building ships during the World War I shipping crisis.  These ships were built with regularly spaced double sistered frames (two layers).  He copied this practice when he drew his ship model plans.

 

Dispite statements in his book about building models just like the real thing, his framing does not represent late Eighteenth Century Royal Navy Framing practice and his brig does not represent what Lexington probably looked like.

 

I once had a hard copy edition of Davis’s book.  If I remember correctly the book included a set of his plans in a pocket.

 

Roger

Edited by Roger Pellett
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The cant frames are depicted as though laying on a flat surface.  If depicted as though in position (canted) on the deadwood, the projections you refer to would line up fair and the beveled surface at the bottom of each half-frame would appear as a line. 

 

I have two editions of Davis' book.  Neither has a pocket for plans.  As far as I know, Davis never produced a set of full-size plans for the Lexington.

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