Lofting

THE MOULD LOFT

This will feature Lofting, its use and some of the history behind the "Black Art" of the Loftsman. 

It was all started a long time ago with a wise old owl in the hayloft of the barn (only joking)

One Loft was the original Ramage & Ferguson Mould Loft and the other Loft was the one originally used by first S & H. Morton and then by Hawthorns & co when they took over the S & H. Morton yard in 1912.

(From the Loftsman collection)

The "Black Art" of the Loftsman, is even to experienced boat builders and to those who would love to build there own, something which tends to confuse and for some a skill to be avoided at all cost. Only due to the fact that it is so little understood and somewhat mystified.

So what is a Loftsman, and what is Lofting, or as I like to refer it "The Geometry of Shipbuilding". So many people have asked me that and when you start to tell them, they just get a glazed look about them, most haven't got a clue and that includes a lot in modern day shipbuilding as well.

The term Loftsman is still found in some shipyards and of course in the aircraft industry, and in the automotive industry it was referred to as a layout draughtsman.

To quote someone from somewhere,

"The shape of a ship's hull, whether it is slim and graceful or full and bulky, is the very essence of its character. This form determines the power required to drive it; it reflects directly the ship's speed; it determines the quantity of payload and the comfort and habitability within the ship; more important, it largely establishes the limits of safety and stability as well as the motion of the ship among waves."

Could not have put it better myself!

In our times nowadays the work of the Loftsman in a shipyard is carried out by no less than four different departments, being that the lines and the surface are done on computer aided design (CAD) you have the surface designer, and then all the plates and steel are produced by the CADCAM dept, the nesting of the plates is carried out by CNC guys using software that completes all the nesting for them automatically, then the Dimensional Control department look after the build accuracy of the ship and then they also have planning/quality departments who now do a lot of what the shipyard Loftsman did as part of his every day work.

It really is amazing to think that it now needs the combined efforts of four different departments to produce what the Mould Loft used to produce all as part of the job, always said that loftsmen were under valued and of course under paid!!!!!!!.

So I guess that's progress for you. Every shipyard had of course slightly different ways of doing things, but the aim was the same for them all.

But it really is the most interesting of jobs for anyone who can, get there head around the basic building block of a ship or boat and in my humble opinion it was and still is the most important and skilled work in the shipbuilding process. (But then I would say that) If you know some or at least the principles of Lofting then any type of design work should come to you with relative ease, the only difficult part is learning all the different computer systems they have today to do the work of the Loftsman.

Should you wish to learn more about how to Loft or require a training course on the subject then please contact Ron@theloftsman.com
Above can be seen the huge Mould Loft floor at the old Harland & Wolff Shipyard. All the ships built their were laid down first on this floor by the Loftsmen including RMS Titanic and her sister ship RMS Olympic.

But dont just take my word for it, as descibed in his book Ironfighters, Outfitters and Bowler Hatters, the Author G. O'Hara tells pretty well how and what loftsmen did as part of the shipbuilding process in the yards of the Clyde from around 1950 to mid 1970's and (Reproduced in its entirety with the kind permission of the author.)

"Loftsmen balk at their collective synonymity with the 'black squad'. Detached and isolated between the drawing office and the shop floor in that what they do and what they made wasn't part of a ship, they nevertheless are an essential and intergral part of the traditional shipbuilding process. Loftsmen are responsible for taking the dimensions, scantlings, and details from drawings and plans,. Translating this information into templates, battens, ordinates, cutting sketches, profiles, margins and other data, whereby steel plates and sections can be identified, cut, shaped, prepared, rolled, formed, flanged and 'set-out' into the primary elements required for ship construction, including the incorporation of additional surplus for weld shrinkage, overbending and cutting allowances.

The summation of skills required for this painstaking job encompass a high threshold of interest, a three-dimensional 'seeing eye', virtually total comprehension of the subsequent fabrication, erection and launching operations, plus diligent dexterity in the art of measurement. All in all a fair spectrum of capability! Not surprisingly these high levels of aptitude were identified as the prime job specification elements required by respective yard managers, chief draughtsmen, fabrication and berth managers, for prospective loftsmen. This senior caucus took a high level of interest in the appointment of the head loftsman with more than a passing interest in the performance of his underlings. If the loftsman didn't get it right first time, then the downstream trades of platers, welders, caulkers and shipwrights would be involved in either considerable costly time consuming re-work, or scrapping of incorrect fabrications.

            A blue collar profession who were part of the shipwright department, loftsmen fared better than their fellow ironfighters with almost white collar working environment. This 'perk' was not reflected in their collective adoption of office working apperal of collar and tie. Modesty, underwritten by conformity, resulted in nondescript sartorial anonymity. The donning of the traditional ubiquitous Clydeside garb of boilersuit underneath a working jacket, usually on top of a collarless shirt virtually hidden by a woollen faded tartan scarf. There remaining visible attire was topped by a worn-out, sweat-stained bunnet, with heavy duty boots as the habitual footwear.

            The wide range of functions carried out by loftsmen, extended from the mundane setting out of the simplest superstructure feature, to the brain-racking traumas of comprehending a stern frame with twin screw propeller boss, bulbous bow, or a long sheered upper deck with flared fo'c'sle.

The loft carried an inordinate responsibility for the good name of the company. Traditional Clyde shipbuilders were aware of this burden from the inception of the industry. The warmest, quietest, driest, brightest, most spacious building in every yard was uaually the loft. This was necessary for essential temperature and humidity control, thus ensuring that the timber floor, incorporating the scrieve board on which the hull and deck lines were drawn full size, as well as all the wooden templates and battens, were kept dry and did not rot, warp, shrink or expand due to temperature differentiation. Any solace bestowed on the industrious occupants was a grudged benefit, often grudgingly regurgitated by polemical shipyard managers when annual wage negotiations took place!

 

 Notwithstanding the new skill plateau that was quickly reached by all the steelwork trades, as a result of the wholesale adaptation of welded prefabrication methods, the responsibility for faultless geometry still remained with the loftsmen; whereas the empirical erstwhile method adopted for steel shipbuilding had been single frame----single plate erection sequence----utilising a greater combination of the individual skills of shipwrights, platers and loftsmen.

This method was a throwback from the times of wooden shipbuilding, when the keel was set out straight and true on the declivity slipways. Transverse ribs were erected at right angles to this keel using ropes and guy wires to retain them in tempory position, until the planks that formed the hull were attached longitudinally to these frames. Steel hulls duly replaced those made of wood. Timber frames were substituted  with rolled sections, called either zed-angles or bulb angles, which were riveted to the shell or hull plating of the vessel.

            This ancestral, laborious method of ship construction allowed the loftsmen the luxury of setting and fairing the steel frames in conjunction with the skills of the shipwrighs and platers. The more difficult task of fitting the steel plates, which were on over 50% of a ships hull, three dimensional shaped profiles, was initially undertaken by using the ships framing as a carcass to provide a solid full-size template for accurate measurement, thus preventing undercutting of the plates dimensions. This additional skilled operation gave birth to the new steel work trade of plater.

            The onset of prefabrication with its hoped for reductions in cost and duration, removed the comfort of the loft being able to lift and verify difficult ship-shape profiles from the building berth. After dimensional scrutiny this information was passed to the plater to form the developed profile of such plates in the plating shop.

This new method effectively killed-off the need for shipwrights and in so doing elevated the standing in terms of technical competence and practical application of the loftsmen. Fabrication shops were added to every shipyard that now used welded methods of ship construction. Each shipyard had its own quirk to assist unit building techniques. These varied from the wholesale building of ship sections, usually upside down utilising the flatness of the deck, hold or tank-top plating which provided a sound working datum, to staggered splicing of shell or bulkhead plating that used the continuity of frames to provide sunsequent location aids for the next adjoining section. This subtle transition of shipbuilding technology was bourne totally on the competence of loftsmen assisted by the practical dexterity of platers, whose collective skills could fashion two-dimensional drawings into real fabrications.

            The high quality of prefabricated ship sections, repetitively produced with consummate ease by loftsmen along the Clyde, inured shipyard management into another niche of self-induced complacency.

This traditional and adaptable method of steelwork development works very well, has worked very well... and will continue to work satisfactorily. A trite maxim that endorsed post-war thinking on most facets of ship construction (as proclaimed by ironfighters and outfitters)... but this edict was being expounded by managements.

Messer-Sicomat A.G. of Greisham, West Germany, revolutionised post-war shipbuilding and all other metal fabrication industries in the same dynamic all conquering style, as the Lincoln Welding Co of the U.S.A. had achieved with electric arc welding earlier this century. The introduction of 'one-tenth scale' profile burning of virtually every plate component, reduced the traditional workload of the template loft overnight. Where the loftsman  was previously reliant on his ability to measure correctly, he now had to acquire a draughting dexterity of flawless accuracy that would enable him to make one-tenth full size sketches on special transparent plastic sheets. These sketches would be optically traced by a 'magic-eye' connected to multiple-head burning nozzles, mounted on a cross-rail above a table containing the plates, which would be profile burned to exact size and shape in a fraction of the time previously taken, using laborious tape and chalk line marking off followed by hand burning.

            These machines, including tables, burning-heads operating console and magic-eye were not cheap! They cost tens of thousands of pounds in the late 1950's, but if they had cost millions they would still have paid for themselves in a relatively short space of time. This nascent technology was accepted unilaterally by management, drawing office, planning office, template loft and most of the platers and burners whose erstwhile jobs this new machine replaced. The process was so high-tech and successful in its day, that virtually every shipyard worker (including welders) whose shipyard invested in these machines boasted to there mates about what these Sicomats could do. Here was an example of management investing....and ironfighters responding....if only the Germans hadn't invented the machine first (sic)

            The natural progression from profile burning was the wholesale use of jigs and fixtures, to assist the set up and fabrication of prefabricated ship units. Used extensively in virtually every UK manufacturing industry except shipbuilding, this technological advantage was never really applied on the Clyde until more than half the industry had vanished! Traditional shipyard managements weaned on a cocktail of semi-aristocratic arrogance, infused with autocratic self belief, propounded 'If we didn't think of that idea first...its not a good idea!' Such quasi-philosophical technical myopia would have been moderately funny...if they were referring to the inclusion of a' la carte menus in the shipyard canteen... (if the yard had a canteen).

Unfortunately, selective comprehension of methods and practises deployed in foreign shipyards was exactly the attitude emergent Japanese and European shipyards needed to assert their ever-increasing commercial advantages. The author goes on to tell a great history of shipbuilding and its demise on the Clyde in Scotland. (It is a must read for anyone with an interest in shipbuilding)

So just what is the history of Lofting? A question that I suppose is lost in the mists of time, and we can only guess that it must have been known to any shipbuilder of long gone times as to build a wooden ship the designer must have had a knowledge of lofting. So it has to go back to the ancient PHOENICIANS times or before 3,000 BC, because to plank a frame the wood first needs to be developed in other words the plank required needs to have a developed shape to it, otherwise they would have to nail some kind of wooden strip to the ships frames and try and pair away at the wood to get it near to shape, and I do not think they would have tried to built a ship this way, more like the great minds of the day would have solved the problem by geometry.

If there really was an "Ark" then Noah would have needed a Loftsman. Ships up to around the 16th century were built on a trial and error basis and if one worked well then others just the same would be built. The shipwright of old would have this knowledge and would have been very reluctant to change once the advent of geometry and maths were added to the science of shipbuilding around this time.

 

The oldest reference I can find dates back to some of the construction books relating to naval ships built in the 15th & 16th century, in the days when only one man would have the knowledge to lay down the lines of a ship.

A classic old Ships Body plan, very well drawn although date unknown.

Although as time went on and vessels became more complex it was the job of the Loftsman to lift all the shapes and template then for the myriad of shaped planks required in wooden shipbuilding.

Moving further on in time to the start of iron and steel ships there was only one way to start the build of a ship and that was to loft the lines and layout the ships shape. This was done by the Loftsmen lifting the templates from the frames of the ship, as the build commenced, a somewhat time consuming process not to mention very skilful as well.

The lifting of templates or moulds as they were known was an art in itself although all this would change due in a large extent to progress made by our American cousins with the advent of the building of the massive New York Shipbuilding Company.

Ground was broken for New York Ship on July 3, 1899. Contracts for preliminary work and equipment for the yard were let within a month. On June 15, 1900, in the sixth month of the new century and the twelfth month of the new yard, the contract for New York Ship's first vessel was signed. On November 29, 1900, the keel was laid.

There were five basic objectives followed in the designing and laying out of the new shipyard. Mr. Morse's advanced ideas were the basis of the planned shipbuilding procedure which he contributed to the industry throughout the world. They were largely the result of his extensive structural steel fabrication experience prior to entering the shipbuilding field.

First, the application of the mold loft template system for the fabrication of hull steel--a pioneer undertaking for shipbuilding at that time but now standard practice in the industry.

Second, provisions for prefabrication of relatively large structural assemblies and continuous routing of material from receipt through fabrication shops and on out to the shipways, a method widely publicized as a new development during World War II.

Third, an unusually complete overhead crane system for handling prefabricated structural assemblies up to 100 tons weight.

Fourth, a coordinated series of shops with five large building ways, and an outfitting basin completely roofed over and served with overhead bridge cranes.

Fifth, installation of propelling machinery and other heavy weights before launching, by providing 100-ton crane capacity over all the building ways.

Of these five objectives, the first--the application of the template system--was perhaps the most revolutionary. In the half century that has elapsed since its introduction by New York Ship this system has come to be standard practice, but in 1900 it was looked upon with grave misgivings.

This system permitted the continuous fabrication of steel from mould loft development of plans which did away with the previous practice of "lifting" templates from work in place before the shop could function. Through accurate mould loft development of templates from plans, the shops are enabled to go ahead with their work for any part of the ship upon receipt of material with the assurance that when a particular part is wanted by the ship erectors, it will fit its appointed place. This of course created a massive shift in the work of the Loftsman and lead to huge savings in time although some very complex shapes would still have to be lifted from the frames on the building berth although even this would change in time.

It was because of New York Ship's experience with these advanced practices that the yard was asked to supervise the designers who laid out and planned the Hog Island yard. New York Ship produced the original templates for the vast fleet of ships built at Hog Island in World War I and assisted in the development of templates for other vessels assembled elsewhere.

In the traditional world of shipbuilding where change happens very slowly this was a real advancement.

Mould Loft at Doxfords-Sunderland

The Mould Loft was built above the plate and furnace shops to begin with, and yes the furnaces would be right below the Loft with all the connotations on health and safety that having a few large open fires directly underneath where men would be working on a specially laid out wooden floor which you could play a football match on.

Every thing about the set up would be pretty special when you look back on things from the timber used in the floor to the fact that the 2" wide x 5" high, wooden strips would be laid out diagonally so that the joins would not be running parallel with any line drawn onto the floor

Old scene from a mould Loft (date unknown) but the templates still looked the same. (photo credit unknown)

The photo above is from an old American Shipyard and they could be making templates for an old Paddle Steamer.
The two Loftsmen here are looking at what could be a template for the forward end of a deck.

As you can imagine the floor of the loft would become a pretty busy place with lines all over the floor, and anyone stupid enough to walk across the floor without permission would be greeted with the usual shout which would go something like "Hey you get off the F**kin lines" or the more subtle "Cant you F*8king read" as the signs around the loft floor left no one in doubt to keep off the floor.

It makes me chuckle a bit when I see pictures of guys working on the loft floor and a lot of them show the loftsmen kneeling on the floor, this I can assure you was never done in the Loft at Henry Robb, as you were told in no uncertain terms that Loftsmen in Leith did not kneel on the floor instead we developed a sort of squat that was a bit like taking a shite, but you were in that position all day, and surprisingly it was reasonably comfortable once you got used to the position, don't know how good it was for the posture or the knees, but that's the way it was.

These Loftsmen got the same advice to keep off your knees.

This is the Mould Loft at Blyth’s Shipyard as seen above.

 Some info and history on how close the Loft and the Drawing office was, not just in distance but in how critical each was to the shipbuilding process, a fact not lost on the drawing office and management in there continual attempts to assimilate the Loft into being a part of the drawing office, repeated attempts were made to get hold of the "Brains with the Practical" to join the "brains" so to speak.

An event that in the end was inevitable with the advent of the computer in shipbuilding.

From a short history on the Blackwall Yard on the River Thames London from the early 1900's

Beginning in the offices of the ship-draughtsmen, where working-drawings were prepared, generally on a scale of a quarter of an inch to one foot. As Dodd was able to pass from these offices directly into the mould loft, the two must have been contiguous. The mould loft was where the drawings were turned into full-size templates or 'moulds' of American deal for the shipwrights to work from. It was a large first-floor room 'about a hundred feet long and forty or fifty wide . . . and lighted by about twenty windows, ten on each side', with a flat, smooth and clean floor on which 'the draughtsman chalks a large number of lines, derived from the working drawings, but enlarged to the full dimensions of the vessel'. Dodd comments 'it is evident, at a first glance, that the chalked floor is a kind of sanctum, a place not to be defiled by the tread of dirty shoes'.

Dodd must have been a visitor to the yard, and the above are some of his observations at the time.

Up until the 1950' and 1960 the ships lines would be run out full size on the loft floor, then with the advent of 1/10th scale lofting this would be done on very long tables and was considered to be a bit more accurate than drawing out lines full size on the floor of the loft, even with the 1/10th scale lofting all the template making of the structural steelwork still had to be laid out full size on the floor and of course full size scrieve boards were still done to enable the ships frames to be formed to the required shape, the laying out and fairing along with the marking up of the scrieve board was an art in itself. The frame lines of the body plan would be laid down once the lofted and faired offsets had been lifted from the completed body plan, and written up in the finished offset book, this offset book would be sent over to the drawing office so they could start to produce working drawings. A half-block model would also be produced prior to this from the same scantling offsets that the loft would start there lines with, at this time from which a shell expansion drawing could be created.

Body Plan of HMS Victory, showing the moulded line to the inside of planking.

The loft would work in different ways depending on which shipyard and there use of lofting, the Leith Shipyards of Henry Robb would take the scantling lines from the naval architect and they would then run and fair the lines through the three views used to reach a fair surface, using the stations provided by the naval architect usually about 12 stations were used, from each station the frames would be drawn out and faired, and using horizontals called "Waterlines" and verticals called "Buttocks" through each view until a perfectly fair ships form was achieved.

 

With the three views used to achieve the fair form would be the Sheer (profile/ side) view and the half breadth view (plan) working between these two views would produce the beginnings of the body plan which was the view looking aft (Port) from the forward end back to the mid-ship section and on the other side and upside down would be the aft view looking forward to the mid-ship section. So in effect one view would be laid on top of the other view to cut down on the amount of space required.

A simplified lines plan with just the scantling sections (in French) shown is seen above, this would then have all the ships frame lines drawn in and faired between all three views. You started off with the frame stations supplied by the Naval Architect, usually 10 frame stations and it was then the job of the Loftsman to fair all the ships frames, their would be many more ships frames than frame stations, depending on the length of the ship.

Above we see the Mould Loft from the Hawthorn Leslie Shipyard and the Loftsmen and helpers are out in force for this photograph, looks like even the foreman is out on the floor (with bowler hat)
Note - Lots of light and space with many templates on-top of the Loft Floor. (Photo copyright unknown)



A view showing only the Aft body, this one is of an old wooden steamship and uses diagonals to fair the sections as well.

 So through care skill and patience the completed body plan would be produced and it would be as fair as the Loftsmen could make it, I say this as every Loftsman would produce a body plan that would be minutely different from the next one, as most of the work required the Loftsman's interpretation of just how fair the lines were.

And a model for tank testing could now be made, for the naval architect to confirm all his original calculations.

The body plan would be faired using the buttock and waterlines along with the frame lines from the other two views. It would sometimes be necessary to introduce some diagonals as well where a line was proving troublesome to fair.

When finished the scrieve (screave) board would then be dismantled and very carefully and accurately re-assembled in the plate bending shop, where the plater's would then be able to bend the ships frames to the required corresponding shape, another very skilled and not to say dangerous job.

There would now be completed and faired profile and half-breadth views along with a finished body plan and the huge job of developing the shell could now be done, in effect the Loft had designed the finished hull surface and now it would all be developed flat so that the plates could be marked and burnt out to the required accurate shape, this was perhaps the most specialised job in the Loft. Every seam and butt was expanded out with a few other secrets of shell expansion thrown in to create the shell expansion plates ready for the "magic eye" burning machine to follow.

All other steelwork was developed out as well from the smallest "beam knees" to the funnel and all nested into part drawings on mylar to draw out the inked parts on, this drawing work was of the highest standards of quality and accuracy as it was all done one tenth scale, it was a job that required the skills of an expert jigsaw puzzle solver to nest (Fit) all the parts into the standard size plates without leaving too much waste on the plate, even the corners had to be the same thickness of line width to allow the burning head to follow without jumping from the intended lines drawn, the line widths were also critical to the process and could not be above 0.7 of a millimetre.

This job of course can be done today by using computer software specially developed just to nest parts with the push of a few buttons (not really as it still takes some skill) although nothing like the skills that we as Loftsmen took for granted as just being another part of the high skill set required to be a Loftsman.

When the lofting was done full size the expanded shell plates would be templated and all the hundreds of templates would be marked up and delivered to the plate shop for manufacture. At the Leith Shipyards of Henry Robb most if not all of the ships built had a lot of shape in them, not for the Leith shipyards the great big slab sided vessels which would make the job so much easier, no the ships built in Leith were one off and pretty specialised ships with complicated and complex shapes with double curvature and compounded angles to take into account.

The steelwork for the hull would all be broken down to manageable sized units of around 20 tons, although of course in a riveted ship each shell plate would be marked for all the rivet holes as well. The contribution of Loftsman to the building of warships by the modular build method during World War II is touched on in this website elsewhere and it is incredible that so few men could have such a large impact on the end result of such a complex process as building a ship. The subject is covered in greater deatail in one of my books in the series They Once Were Shipbuilders, Leith Shipyards at War.

Meanwhile all the rest of the steel work that made up the finished hull and super-structure would be templated and/or lined off on dressed wooden battens for the platers and shipwrights to then mark off from, this meant that because most of the work had already been checked and marked off by the Loft there was less room for error in the marking process. The marked battens had all the relevant "ships datum's" and all other steel parts on them, a job that shipbuilders of today could do with remembering and this all in all made the plater (or shipfitters as our American shipbuilders call them) and the shipwrights job that little bit easier.

The Loft would produce hundreds of drawings of the steelwork required to build the ship along with perhaps thousands of templates and battens, and at the same time take control of the dimensional accuracy of the erection of the units in the plate shop and on the inclined slipways, referred to as the "berths", with a ratio of (in Leith at least) one Loftsman to around 150 to 200 other shipyard workers you can start to see that it was a pretty specialised job.

Portsmouth Mould Loft-1891

 This is a photo of the Mould Loft at the Portsmouth naval shipyard, and the Loftsman is not "drunk" and about to fall over, but fairing a line. You can also see that the Loft was surrounded by glass in the sides and the roof to give as much natural light as possible, great in the winter but it could be a real sweat shop in the summer once the sun rose and started heating up the place.

The photograph above shows the mould Loft from the famous John Brown yard on Clyde-side where some of the most famous ships ever built were laid down and lofted.


This was a large loft and it had to be to enable the lofting of ships such as the QE2 and the previous Queen Mary and her sister Queen Elizabeth along with many other huge vessels. This was a staged photograph taken during World War Two and it must have been taken on a day off for the yard, as they were building many of the largest warships at the time for the Royal Navy.


Photograph is from the Imperial War Museum Collection

The photograph above is another staged photograph done by Cecil Beaton, during WW2, this is from the Imperial War Museum collection. The two Loftsmen are working on the mould loft floor checking measurements with a long template in front of them.

The photograph was taken during World War Two, a time when every shipyard in the British Isles was working to full capacity.

Loftmen fairing a ships frame lines, or running the lines as it was called in Leith.

 The photograph above shows a staged picture of two Loftsmen fairing a batten for the camera in this Imperial War Museum photograph.


A bad back was almost guaranteed whilst running body lines full size for the scrieve (Some spell it screave) board.


You can clearly see the scrieved frame lines of this ship as they wrap a batten around the shape.

Mould Loft-Harland-Wolff

Interesting photograph shown above of the Mould Loft at the Harland & Wolff Shipyard where they built many fine ships, note the lines on the Loft floor showing part of a body plan full size, and lots of light on each side of the Loft, and yes this is also where the Titanic’s lines where laid down along with so many other famous ships during there long history.

 

The scrieve board seen here is made up of many long plank strips all joined and pinned together so that once completed they would all be lifted and taken down to be placed beside the frame benders so they could work from the board to shape all the ships frames. You may also note that there were few hiding places; this was not a place for skiving.

A Sheer (profile) view of the majestic liner “Canberra” will we ever see such ships again?

A ship was always drawn to a set convention that showed the three primary views, the sheer or profile was always drawn looking to port from the starboard side. The Body plan always showed the port side looking forward to aft, with the plan view always showing the port side. As above in sheer or plan view the vessel always has her bows facing to the right-hand side.

A scene from the Mould Loft, with couple of Loftsmen moving a finished template in this Cecil Beaton photograph taken during World War Two.

This is from an unnamed Tyneside shipyard, but could be any Mould Loft with the finished template ready with all rivet holes drilled out in the template ready for the Plater to mark out directly on the plate.

It is the same for wooden boats, but the big difference with lofting for non-steel vessels is you do not have the mind-numbing challenges of shell plate expansion & development. Another difference between lofting a wooden boat as opposed to a larger commercial type vessel, is the Moulded surface, in a steel ship the moulded line or surface is the inside of the hull (or shell) whereas a wooden vessel will usually be lofted to the outside of the planking, so the moulded surface is to the outside with the thickness of the timber inboard, the opposite is usually the case with steel. I say usually as I have known unusual cases where the moulded surface is taken to the outside of the steel hull, but this is not the norm.

A typical Mould Loft at work and not staged for the photographer, templates being worked on with a lot of activity happening, much more like the real thing.

All of which brings me on nicely to a neat Blog that was written a few years ago by Steve Zimmerman of Zimmerman Marine as shown unabridged below –

I am happy to say that I now have permission to use the following from Steve who has kindly told me to go-ahead and use his words. I do love it when other Loftsmen put down in words how learning the “Black art” influenced them so much.

The Lost Art of 'Lofting,' as Learned from the Master

Updated:

Apr 21, 2017

Original:

Dec 3, 2013

In the late 1970’s I began my boatbuilding apprenticeship in Maine with one of the great American boat builders, Paul Luke. I earned my way into the boatbuilding crew after surviving their best attempt to drive me away by assigning me to drill and tap thousands of wing nuts in the machine shop, but that is another story.

Paul Luke

My favourite part of the entire process took place at the beginning of a project, on the loft floor. In those days you began building a boat by converting the blueprints into a life size drawing of the boat. We were building sixty plus foot boats and that meant an area 12’ wide and 80’ long. Not just any area, but a white freshly painted floor known as the loft floor.

In an otherwise dingy shop, the loft floor had its unique charm. First, it was above the shop, separate, and dedicated to this one purpose. Drawing in pencil on this floor required light, and one entire wall had windows, with a view out into Linekin Bay. From this lofty view we could gaze out over the water, or look down into the shop below.

The loftsman, Earle Dodge, was a no nonsense set in his ways master, even dictating which pencils I should use (Venus Velvet, 2.5). In his lone concession to anything other than pure concentration on our work, Earle allowed himself one diversion. Each day when the whistle blew at four o’clock, Earle would take his Venus Velvet and make a mark on the wall where a window frame cast its shadow, and then the date.

Sure enough, each day the mark moved slightly as the earth’s angle to the sun changed.

I found the lofting process fascinating. The process went something like this: layout a grid on the white painted floor, reproduce the lines on the blueprint at full size on the floor, find and correct any humps and bumps that were not visible at the blueprint scale, and then generate a set of patterns to be used to create the frames that would form the structure and shape of the boat. Sounds easy right?

The drawing process begins from a list of numbers known as a “table of offsets.” Hidden with the numbers are graceful sweeping lines that define the boat’s shape.

Lofting can be a challenging mind-bender. The designer creates the shape of the boat with three different views. Imagine your coffee mug. If you sliced it horizontally into many pieces, the bottom of the cup would appear as a solid disk. The areas above it would appear as rings. Depending on the shape of the cup, the rings at the bottom might be larger than the rings at the top. Now imagine slicing it vertically. These slices would all look very similar, except for the handle. The designing process slices the boat in three different ways, and these slices are all reproduced full size. Adding to the fun, in the interest of efficiency, all of these pencil lines are superimposed on each other. It can be mind boggling.

The lofting process refines all of the numbers and lines and distils them down to a “body plan.” The right side of the drawing looks aft from the bow, while the left side views from the stern looking forward. The boat has been sliced across into sections. A pattern is made of each section and the patterns are used to create moulds or frames which establish the shape of the hull.

At the end of the process, the lines are all reconciled into what is known as a body plan, and from the body plan the patterns are made for the frames and construction begins. It all seemed rather magical to me and now, with the benefit of time, I have some understanding. Any time that we imagine something in our minds and then create it in the physical world, there is some magic (and hard work usually), to that process.

 

The creative spark that flashes, seemingly on its own, leads to an idea, expands to a vision or plan, and then becomes a physical reality. I have found that to be true whether building a bird house, a boat, or a business, and when it happens the feeling is so gratifying.

Sadly, the lofting process has gone the way of penmanship and handwritten letters. Computer programs generate the dimensions, and five axis, computer controlled routers carve out three-dimensional moulds.

 

I treasure my memories of days spent high above the shop drawing graceful pencil lines on the freshly painted white floor, with sunlight and a breeze coming in from water.

At the pattern phase, we begin to see the boat shaping into something.

Started in 1981, Zimmerman Marine specializes in all aspects of boat service, including “everything from minor repairs to major refits.” Zimmerman Marine has service facilities in Maryland, Virginia,  North Carolina and South Carolina. The company also builds semi-custom cruising boats and offers its own line of downeast-style cruisers. www.zimmermanmarine.com

 

By

Steve Zimmerman of Zimmerman Marine

Below is a render of a recent new build by Zimmerman Marine

Many thanks once again to Steve for the story above, as he says great memories.

CAD Lofting

Computer Aided Draughting 

With the advent of the computer, lofting was right in the fore-front of CAD (Along with the fashion industry) and while this is not the place to go into it, when you look at the majority of ships today you will see that they have very few nice shapes to them.

This, in my opinion, is, of course, a saving in time, therefore, money as it is easy to develop a nice flat shape and you don't need the same type of skill set to do, but the end result is somewhat poorer shall we say and leave it at that.

In general commercial shipbuilding rarely will you see a beautiful raked bridge front angled on all sides with curvature all the way up, or a nice raked funnel all of which took into account the fact that a curved shape that was "fair" created less wind resistance and hence less fuel to burn to get to your destination.

We are more likely to see what looks like a box structure plonked on the aft end of a boxy-looking hull as this is more economical to build and should make the shipowner more money in the short term.

CAD Ship Lines

A typical view of a CAD model, this one shows part of a container ship's lines.

It has to be said that the American Shipbuilders (see New York Shipbuilding Company) contributed a lot to the progress of and the use of Lofting, at the turn of the 19th century.

They were leaders with the use of templates being made to ensure that the full-size part was correct and in issuing full-size templates to the plate shops the risk of a plate not fitting and therefore expensive re-work was vastly reduced.

A message that some of today’s shipbuilders would do well to heed in this day of just forcing everything to work to a budget, never mind the quality, they don’t seem to see that with the more time spent getting it right first time the less overall cost and better job is produced. You can always get the lazer beam onto the job now, so there should be no re-work, right!

Along with the need for templates for the developed shell plates complete with all the rivet holes marked, the need arose for the provision of bevels as the ships frames lie at 90degrees to the ships centre line, this means that on a frame made from angle section the flange of the angle plate needs to sit flush on the shell and to do this the flange of the angle section had to be formed to the bevel of the frame.

Other problems solved by the Loft involved the complex areas of the bow where the anchor recess was placed and the run of the hawse pipe through the recess, this would usually be laid out on the floor at a working scale which would entail the construction of a quarter size mock-up.

This would be assembled in the Loft complete with a scaled wooden anchor to ensure that the anchor worked when housed into the recess and the anchor did not damage the shell on raising and lowering. Once the mock-up was made this would be shown to the incumbent Lloyds surveyor for his satisfaction that there would be no problems with the design and workings when manufactured and in the bow of the ship.

More mock up's would be made of things like stern rollers and complex funnel shapes along with bulbous bows. With the mock-ups generally being made from yellow pine, a wood that is very good to work with and clean too.

Every shipyard had it's Loftsmen and most Lofts worked roughly the same way until it came to the complex problem of shell plate development, some yards used the Triangulation method as they did at Leith while some yards used the Square Line method, both were just as complex and both resulted in the shell plate development and expansion required.

One yard which used the Square Line method and produced some of the finest looking ships was the shipyard of Charles Connell in Scotstoun, on the River Clyde.

This was a much larger shipyard than Henry Robb at Leith and as such required the use of more Loftsmen, one of the old Connells Loftsmen has kindly sent in a photograph of the Loftsmen from June 1954.

The Loftsmen of the Charles Connell Shipyard, Scotstoun,
Glasgow taken in June 1953

Sent into the website by George Lamb and shown here by
permission.

(The names are left to right;)

Back row; Harry Hamilton, George Lamb , John McManus,(assistant
foreman) John Conner, John Dalziel,

Mid. row; Willie Stephen, Jackie ?, Willie McKay,

Front row; David Cowan, Peter Weir, Allan Heron, John
McKay

There was also the lad who took the photograph, Ronnie McLaughlin

Interestingly enough the shipyard of Charles Connell were also well known for producing some very fine ships and they in fact built
around 17 ships from 1917 to 1967 for a very famous Leith Shipping Line namely
the Ben Line who's many fine-looking ships got to be called the "Leith Yachts"
by the men who sailed with Ben Line such was there look.

MV BENVRACKIE built by Connells 1958

A typical Ben Line "Leith Yacht" from 1958 built by Connells

The photograph is from a fine website run by Bjorn Larsson

The days of the tenth scale or full-size Lofting may now be gone, although most Naval Architects if they could would certainly try and run ships lines at a reasonable scale as the eye is the ultimate check when it comes to fairness of form.

There is no computer that I am aware of that can differentiate just what a fair line is, just as no two Loftsmen would ever agree on any one fair line, running lines was a one-man job. I think it would be safe to say that any Naval Architect or Designer would benefit from knowing Lofting, really knowing the art of Lofting could only make the designer on the computer better at his or her job, to leave all to the software is asking for trouble especially when it comes to putting the panels and plates together.

See my pages on Lofting & Design Services.

So CAD it is and no doubt about some of the software programs they do make things so much easier and with some such as nesting software takes a lot of the thinking, some may even say drudgery out of this sometimes complex challenge.

How to get the most out of an expensive plate of shipbuilding grade steel has always presented a challenge, now some of the nesting software does this in minutes when it would take us days. That is not to say that all the parts are correct of course, that is up to whoever has designed the parts in the first place, with more knowledge about Lofting they could not fail to be better at their job.

Many designers of today are not even sure what a Loftsman was/is and the ones that do have but a vague idea of what they think it involved. it is hoped that if you have reached this far then you will indeed have a better idea of what Lofting is.

Plt-nesting-1.jpg

You can see a typical nested plate above, this used to be done using an ink pen on Myler, now the software churns it out very quickly.

A typical template is shown below-for perhaps a bulkhead or such now superseded by nesting software, as shown above.

TO BE CONTINUED, KEEP CHECKING BACK FOR MORE ON LOFTING, WHAT IT IS & THE HISTORY BEHIND LOFTING.

  • Facebook
  • Instagram

© 2020 by R.O.Neish

Designed & Developed by Lucid Media