Harold Hahn method

[allanyed]

Tim,

Sorry to continue with spending money and researching suggestions, but.............

You can learn a lot about "the method" in The Ships of the American Revolution and their models by Harold M. Hahn. ($13 for a used copy at Abe books) 

For a somewhat complete explanation from start to finish of "the method" , maybe consider continuing your search and check out the Beavers Prize build log here at MSW.   

 

Allan

[Gregory]

There is some comprehensive information about Hahn and his models here:

 

Harold Hahn - The man and his models

[RegAuthority]

Intense, highly educational and showing me how much I have yet to learn.  
 

Thank you all for sharing all this information and links, am actively devouring it to understand the discussion.  

[Justin P.]

3 hours ago, allanyed said:

maybe consider continuing your search and check out the Beavers Prize build log here at MSW

For anybody who (like me) immediately went looking for it: 

 

[Roger Pellett]

As requested, a brief description of the Hahn Method:

 

This method was an outgrowth of Charles Davis’s Built Up Ship Model Book and is based on an assumption, not valid for all real ships.  The assumption was that real wooden ships were built with two layer (sistered) frames, regularly spaced, known as “room and space.”

 

Hahn also had access to a full sized table saw (8in) and plenty of lumber.  As a professional model maker, he continued to use his method even after switching to more expensive Boxwood.  He was not limited to buying precut sheet stock from others.

 

The Method:

 

1.  On the sheer view of the lines drawing draw a straight datum line above the highest point of the vessel’s sheer.  The datum should be perpendicular to the vertical stations on the sheer view.  Project this same datum, at the same height above the top of the body plan.

 

2.  On the body plan extend the top of each station (section) vertically until it intersects with the datum.  These vertical extensions will be parallel to the body plan centerline.

 

3.  Loft and vertically extend per 2, additional body plan sections as needed to satisfy room and space.

 

4.  Plot the point where each body plan section extension from 2 and 3 meets the datum on a plan view.  Pass a curve through these points.  Glue the drawing to a flat board and cut out the shape bounded by the curve.  You will use the area outside of the curve.

 

5.  Eyeball the body plan sections and draw standard oversized patterns for the the frames represented for the lofted body plan sections in 2 and  3.  These patterns allow the rough frames to be made from  straight pieces of framing material with mitered joints between sections.  Each rough framing section is constructed in two layers glued face to face.  The mitered butt joints in the top layer should be staggered from those on the bottom layer.

 

6.  Rubber cement a copy of each lofted frame onto the rough framing section.  Cut out the finished frame.

 

7.  Use the board with the cut out plan view to build a jig to hold the cut out frame sections in the upright position with the frame extensions flush with the bottom of the jig.

 

8.  Glue the frames into the jig.  You will be building the model upside down.

 

9.  Add keel, stem, stern, etc.  Fair framing, and stabilize hull structure with planking.

 

10.  Cut hull structure from jig along sheer line.

 

 

As Jaager has posted,  an investment in NRG’s Shop Notes is well worth the $35 cost and includes a complete description by Hahn of his method along with drawings to build a model.  He has done all of the lofting for you.

 

Besides, you support NRG and the forum.

 

Roger

 

 

 

 

 

 

 

[mtaylor]

16 hours ago, Tim Holt said:

I think some of us would like to see a clear definition and examples of this method.  I'm getting some hints from the comments, but examples (pictures and build logs) speak louder than words sometimes.

 

Tim,

I have the Hahn Licorne in my signature. Note that it wasn't finished but will give you an idea on how it's done.   Also, you can search using the site search with the key work "Hahn" and choose options to limit it to the title of build logs.

 

And has been said before, one does not have to use his method of making the frames.  There are other ways, such as laying out the timbers needed to make the frames, cutting them out, and assembling. 

 

Hahn's book, "Ships of the American Revolution" details his methods and also why he made the choices of the models in the book.  Last I checked it's still reasonably priced and a good investment as he details in the last chapter doing not only the method but also the complete build of Alfred.

[Dziadeczek]

20 hours ago, Jaager said:

Your hull looks spectacular.   Since the term  has no exact meaning, you might as well call it Admiralty style.  Are you going to use full planking above the wale?

 

THANKS.  😀   Yes, I did it.  (The pic I attached is now, sort of, old...)

The more current state of affairs is here (entry # 60) + recently I attached all 5 anchors as well.

 

[Essayons]

On 11/2/2021 at 3:41 PM, mtaylor said:

Tim,

I have the Hahn Licorne in my signature. Note that it wasn't finished but will give you an idea on how it's done.   Also, you can search using the site search with the key work "Hahn" and choose options to limit it to the title of build logs.

 

And has been said before, one does not have to use his method of making the frames.  There are other ways, such as laying out the timbers needed to make the frames, cutting them out, and assembling. 

 

Hahn's book, "Ships of the American Revolution" details his methods and also why he made the choices of the models in the book.  Last I checked it's still reasonably priced and a good investment as he details in the last chapter doing not only the method but also the complete build of Alfred.

Yes Mark! That was my initial question on Hahn's framing method, the upside down method, but mixed with conventional frame method of cutting out each futtock and assembling them.. I think it will take some study to build the jig pattern. If it were a RN subject where the upper futtocks varied in thickness(sided) and relative position to each other frame(use the HMS Euryalus 1803) for example. On the other hand, I have the Ancre book/plans for the Hermoine. Their drawings show a constant room and space of ~24"/12" all the way up to the upper futtocks, so making a Hahn-syle jig could be very feasible. 

Randy

[Jaager]

4 hours ago, Essayons said:

If it were a RN subject where the upper futtocks varied in thickness(sided) and relative position to each other frame(use the HMS Euryalus 1803) for example. On the other hand, I have the Ancre book/plans for the Hermoine.

As far as RN framing is concerned,  you could always "eat the mushrooms!" and use one of many stylized framing alternatives.  To my eye the actual RN framing  has almost zero artistic merit.  It was purely functional, based on necessity, was not intended to be seen and looks it.

 

The French and North Americans tended to frame using all bends and a minimal number of cant frames if any. 

 

Be very careful with Hermoine.  Especially if you use the individual bend/frame patterns in the monograph.  The author of that monograph often folds in problems in his lines and lofting work.   Fixed with a little or a lot of work - depending on the ship - Hermoine = minor   St. Philippe = major.   There are more attractive French frigates in the ANCRE inventory. 

[Gregory]

Just to add another twist to " Admiralty " ( Navy Board ) style.

 

I recall seeing a number of these at the NMM:

 

 

 

 

The text in part:

 

Quote

scale: 1:48. Georgian full hull model, with elements of Navy board style, of a sixth rate 12 gun sloop (circa 1720). The open frames have been painted onto a carved pine carcass hull below the waterline.

 

I don't recall ever seeing a build here, where the spaces between frames were painted onto a solid hull.

 

 

 

Edited November 9, 2021 by Gregory

[Roger Pellett]

Cold that have been the mass market Admiralty model?  The Eighteenth Century equivalent of the priceless models now offered on EBay?😁

[Jaager]

There is a model of Centurion 1732 at the NMM that is also a solid hull that was painted as though it was Navy Board.  

It seems to me that the peak of actual Navy Board was ~1670.  The builders of the +/_ 1740  simulated Navy Board would likely have been 2 or 3 generations after the actual built up style was de rigueur.   The actual shops that built them were long gone?   The actual way to do it lost?   The sponsor was not willing to pay for the additional cost for the built up version?   The suppliers or supplies of the wood stock needed no longer existed?

 

In their Hay Day the framing style of Navy Board models probably reflected an artistic version of then then dominant (or a past and going out of style) of the actual framing of the ships they represented.   By the mid 18th century,  it was replaced by "modern" and "scientific" framing style of bends and filling frames ( with many variations on the theme ) that more or less continued until it was replaced by iron frames. 

Perhaps enough time had passed using the new framing for there to be allowed to develop a sense of nostalgia for the old and long defeated framing style?

Edited November 9, 2021 by Jaager

[Gregory]

Here is a search for models with key words " Navy Board "

 

Most of them are pre 1700.

 

Centurion 1732 shows up..

 

 

[J Merton]

On 10/27/2021 at 6:27 PM, mtaylor said:

There's been several builds using the Hahn method.  As for the scantlings... I don't think so.  For the most part, those of us who did a  Hahn build used his plans with minor mods as needed. 

 

I really don't see a problem doing one using the scantlings and the Hahn method.    His method was introduced to help make things "easier" for model builders, not to dictate style.

How does the term 'scantlings' apply to the Hahn method. The internet is rather vague on this term. Thanks

[mtaylor]

His method is based on doing your drawings for the framing.  Then you glue up some blanks, attach the framing plans and cut.  It also involves making the build board and extending the framing top ends out to fit into the build board.  

 

Have a look at my Licorne build as it was done using the Hahn method. The link is in my signature.  Also, I did find this video:  

 

 

[Roger Pellett]

Hahn’ double sistered regularly spaced frames are a gift from Charles Davis who worked building large wooden vessels during the shipping shortage caused by U Boat losses in WWI.  In his book, The Built Up. Ship Model Davis wrote that “This is how real ships were built.”

 

Fast Forward 100 years, and the standard has become Fully Framed POF models using exact Admiralty Framing practices, although the authors of books on this subject do not echo Davis’s claim of universality.

 

Construction of real wooden ships with the Davis/Hahn framing or the more complicated Admiralty framing required full sized patterns copied from full sized lines on a mold loft floor.  The lofting in turn required a digital tabulation of dimensions taken from a scale drawing or half model.

 

In fact, the picture is much wider.  Thousands of wooden sailing ships were built under primitive conditions by artisans not schooled in preparing Admiralty style draughts.  They relied on shorthand techniques to shape keel, stempost, sternpost, and a few widely spaced frames.  Whole molding was one of these techniques.  Once these few frames had been erected, planking could begin.  Filler frames would be added along with planking.  Sometimes segments of these filler frames would only be fastened to the planking, not to the keel or to adjoining frame segments.  See Charles W. Morgan 1845 or Lake Champlain 1758 British Sloop Boscowan.  I personally doubt if the framing of Colonial Schooners looked anything like Hahn’s models.

 

Colonial shipwrights could frame up a hull in remarkably little time.  Arnold’s 1776 Lake Champlain Row Galleys were each built in less than a month’s time, almost certainly from molds brought North by shipwrights who had built similar craft to defend the Eastern Seaboard.  There was no time for careful lofting.  Despite this, the plans commissioned and sold by the NRG for the 1776 Row Galley Washington show regularly spaced double sistered Davis/Hahn frames.  Some things don’t change.

 

Building the model right side up or Hahn Style upside down does not prevent the builder from realistic framing practices.

 

Roger

 

 

[mtaylor]

Well, Hahn admitted that his framing is "stylized" and gave a few reasons... simpler to construct, the opening between frames gave the hint of what the framing looked like and also allowed his cutaway areas to be built easily.   He also admitted to it being very wasteful of wood.

[Gaetan Bordeleau]

Roebuck from the plans of H. Hahn

 

With the help of his book Ships of American revolution, I jumped in the scratch built models.

I remember when I did it more than 30 years ago, It was very scary for me to enter in this category, there are so much details in the construction of a ship.

Harold Hahn even if he did simplified the details was a very good builder and carver too.

 

[Tim Holt]

3 hours ago, mtaylor said:

did find this video

 

Thanks for the video Mark - quite nice to watch.  Helps me with the "so what is the Hahn method?" question.

Edited January 9, 2022 by Tim Holt

[allanyed]

J Merton

First, welcome to MSW!!! 

It sounds like you are referring only to the scantlings of the frames.  These would be different for the Hahn method compared to a fully framed vessel.   For British ships, scantlings cover pretty much every piece of a ship, not just the various parts of each of the frames.  These dimensions changed over various periods of time and of course vary for different size vessels.    A full set of scantlings can be found for the 1719, 1745, and 1750  Establishments, the Shipbuilder's Repository (1788) and Steel's Elements and Practices of Naval Architecture (1805).  To the best of my knowledge, a complete set of scantlings is not available on the internet.    If your ship was British and built in a private yard, there may be a contract available that also gives scantlings for the various pieces of the ship.   If you are talking about an American vessel, the scantlings for an appropriatie period should be relatively close to the British.    

 

I PM'd you one folio from Scantlings of the Royal Navy  

 

Allan

 

 

[druxey]

Here is an example of the open 'Navy Board' style of framing. Note that the model was built right side up, with no wasted extended toptimbers.

[allanyed]

Druxey

Your photos bring up a very important point regarding the huge waste of wood  when using the so called Hahn method.    I built one model with this method many years ago and the cost of material for the framing was triple that of the method that you show and double that for a fully framed model.  With the Hahn method,  gluing overly sized pieces into sandwiches then cutting out the frames is expensive and considering the cost of quality wood today, the savings of using more traditional framing methods is significant.   
Allan 

[Roger Pellett]

Harold Hahn developed his method in the 1970’s.  At that time there was also a series of articles running in the Nautical Research Journal about harvesting and using native hardwoods.  Hahn used maple for his first models including the Schooners for his shipyard diorama.  Real Boxwood was also available commercially from specialty lumber dealers.

 

Those of us who got involved in harvesting our own wood found that we could easily cut and mill enough wood for several lifetimes of model building.

 

I believe that when Hahn first developed his system wood waste was not a concern.  Once he switched to Boxwood, he made the comment about wasting material.

 

Roger

[Charles Green]

With Hahn's method of framing, there is a lot of wood trimmed away but it should not be categorized as "waste".  There will be plenty of opportunities to use the pieces further on in the build. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Gaetan Bordeleau]

Whether using Hahn method  or any other method, framing, because of all the curves involved,  will always generate a lot of waste..

I filled 2 of these with a standard method.

Edited January 10, 2022 by Gaetan Bordeleau

[mtaylor]

If I were to do another Hahn plan model, I seriously think that I would cut out the individual pieces for each frame and then put them together.  Even "common" woods are getting a bit pricey.

[druxey]

In fairness to Hahn,  he used this for small-scale models, not large 1:48 scale ones. The wastage was significantly less.

[mtaylor]

4 hours ago, druxey said:

In fairness to Hahn,  he used this for small-scale models, not large 1:48 scale ones. The wastage was significantly less.

That's very true. Thanks for pointing that out.

[Jaager]

10 hours ago, Charles Green said:

There will be plenty of opportunities to use the pieces further on in the build

Except that the waste is two layer "plywood" with some of the layers at 30-45 degrees to each other.  This is difficult to use for anything else.  It could be soaked in IsoOH to separate the layers I guess - but the scrap is irregular in shape and probably not worth in savings what it would take the rescue it.

 

I did not consider the waste per  scale aspect when I framed Kate Cory @1:48, back in 1973.  It is obvious, now that @druxey has pointed it out.  At the time, I would have used the Hahn method anyway.  The alternatives were very complicated.  I used Black Walnut and it was inexpensive and easy to get. 

 

 

The waste of 1:48 is 4 times Hahn @ 1:96

@Gaetan Bordeleau @ 1:24 has 4 times the waste of 1:48   as well as starting with thickness of framing  stock that is 2x 1:48 and 4x Hahn

 

When Hahn introduced his method, it was easier than the methods used then.   The upside down aspect is a choice.  It works just as well if not rotated 180 degrees.   The plywood jig that holds the extension of the tops is easier to mount and is less likely to bow or twist when secured to the baseboard.  The jig wants extensive and precise bracing when hanging in the air.

 

[Juddson]

I don’t mean to add to the confusion, but I am confused by the references above to whether one framing method or style versus another includes 20% or more or less “spacing” between the frames.  This would seem to suggest that the number or width of the frames used in the models were a matter of style rather than a reflection of what the plans called (Which I understood to be actual reflections of the original framing of the ship itself).  Am I confused, naive or both?