The Loftsman
Leith Shipyards

A history of the Ships built at the Henry Robb Shipyard in Leith, Scotland. Also a testimony to the men who built the Ships and to all who sailed in them.
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Ship and Shipbuilding Terms

This is where we shall introduce you to some of the terms used in building a ship, from "Baw Hair" to Starboard, and many, many more as we go along most from a time long before any of this so called political correct-ness. When a spade was a spade and a shovel was a shovel, no more no less.

Every Naval architect or shipbuilder should be familiar with the technical names denoting ship lines, surfaces, and dimensions. Familiarity with these terms is essential in reading blue prints (Ship Drawings) and in building and installing parts of a ship if you dont know what things on a ship are called then how the heck can you build a good ship. If you dont know where you are on a ship then you are just lost.

"I think it's F%*ked!" - Meaning (The required process has not been followed)

"Baw Hair" - To mean the thickness of a "Pubic Hair".

"Starboard" - From an old Viking word where the had a steering oar known as a Styrbord.

"He disna have a Scooby" - meaning "that chap has not got a clue what he is speaking about". (Scooby Doo-Clue)

The "Black Squad" the collective name for all the steel working trades that built the ship

"Iron Fighters" a calloqual west of Scotland Clyde shipbuilding term for the above named "Black Squad"


There is a lot of confusion caused by all the different terms and measurements used in ships so here we will try and give a simple guide to some of the main ship measurements.

Beam - The width of the ship

Complement - The full number of people required to operate a ship. Includes officers and crewmembers; does not include passengers. For warships, the number of people assigned to a ship in peacetime may be considerably less than her full complement.

Cube - The cargo carrying capacity of a ship, measured in cubic feet. There are two common types:

Bale Cube (or Bale Capacity)- The space available for cargo measured in cubic feet to the inside of the cargo battens, on the frames, and to the underside of the beams. It is a measurement of capacity for cargo in bales, on pallets, etc., where the cargo does not conform to the shape of the ship.

Grain Cube (or Grain Capacity)- The maximum space available for cargo measured in cubic feet, the measurement being taken to the inside of the shell plating of the ship or to the outside of the frames and to the top of the beam or underside of the deck plating. It is a measurement of capacity for cargo like grain, where the cargo flows to conform to the shape of the ship.

Displacement - A measurement of the weight of the vessel, usually used for warships. (Merchant ships are usually measured based on the volume of cargo space; see tonnage). Displacement is expressed either in long tons of 2,240 pounds or metric tonnes of 1,000 kg. Since the two units are very close in size (2,240 pounds = 1,016 kg and 1,000 kg = 2,205 pounds), it is common not to distinguish between them. To preserve secrecy, nations sometimes misstate a warship's displacement.

Displacement, Light - The weight of the ship excluding cargo, fuel, ballast, stores, passengers, and crew, but with water in the boilers to steaming level.

Displacement, Loaded - The weight of the ship including cargo, passengers, fuel, water, stores, dunnage and such other items necessary for use on a voyage, which brings the vessel down to her load draft.

Deadweight Tons (DWT) - The difference between displacement, light and displacement, loaded. A measure of the ship's total carrying capacity.

Cargo Deadweight Tons - The weight remaining after deducting fuel, water, stores, dunnage and such other items necessary for use on a voyage from the deadweight of the vessel.

Draft, Loaded - The depth of water necessary to float a vessel fully loaded.

Moulded Line – Is where all design measurments start from and are measured to.

Length - The distance between the forwardmost and aftermost parts of the ship.

Length Overall (L.O.A.) - The maximum length of the ship

Length at Waterline (L.W.L.) - The ship's length measured at the waterline

Shaft Horsepower (SHP) - The amount of mechanical power delivered by the engine to a propeller shaft. One horsepower is equivalent to 746 watts in the SI system of units.

Ton - The unit of measure often used in specifying the size of a ship. There are three completely unrelated definitions for the word. One of them refers to weight, while the others refer to volume.

Measurement Ton or Ship Ton Calculated as 40 cubic feet of cargo space. (Abbreviated M/T). See Bale Cubic - example, a vessel having capacity of 10,000 M/T has a bale cubic of 400,000 cubic ft.

Register Ton - A measurement of cargo carrying capacity in cubic feet. One register ton is equivalent to 100 cubic feet of cargo space.

Weight Ton - Calculated as a long ton (2,240 pounds) (abbreviated W/T)

Tonnage - A measurement of the cargo-carrying capacity of merchant vessels. It depends on, not on weight, but on the volume available for carrying cargo. The basic units of measure are the Register Ton, equivalent to 100 cubic feet, and the Measurement Ton, equivalent to 40 cubic feet. The calculation of tonnage is complicated by many technical factors.

Gross Tons - The entire internal cubic capacity of the ship expressed in tons of 100 cubic feet to the ton, except certain spaces with are exempted such as: peak and other tanks for water ballast, open forecastle bridge and poop, access of hatchways, certain light and air spaces, domes of skylights, condenser, anchor gear, steering gear, wheel house, galley and cabin for passengers.

Net Tons - Obtained from the gross tonnage by deducting crew and navigating spaces and allowances for propulsion machinery.


"Soft Nose"- The upper strakes of plate that formed the bow of the ship, from the solid stem bar to the main deck.

"Breast Hook" - The brackets that held the shape of the soft nose.

"O.Gee." - The line of the shaped plate that formed the 3D line from the main deck to the forcastle deck at the ship side. 

"Window Lickers" - The less well skilled tradesmen.

"Strong Back" - A heavy plate used as a fairing aid to keep plates straight and fair and to asist in the alignment before and during welding.

"Beam Knee" - A bracket holding the transverse deck beam to the vertical frames at the side of the hull.


"Howff" – The inner sanctum within some shipyards, usually trade specific so the shipwrights in there various groups would have “Howfs” scattered around the shipyard and the platers would have there own “Howfs” and welders and so on.

A hideaway where groups of men can gather to get changed and have a cup of tea or other, they also had mealtimes in the “Howf” which could at the time be no more than a small shed or discarded container, but it was jealously guarded and there was a strict entry system to those Howfs. Some of the “Howfs” had the serious card games going on while some “Howfs” were no more than “Gang Huts” and of course some of the men did not use "Howfs" but would spend most of the time close to where they did most of there work.

Foremen and bosses for instance would not go near them, instead they would send someone to have a look to find whoever, and in later years some of the foremen got brave and would poke a head in while chasing the men out to work.




A scene from a typical "Howf" at the Leith Shipyards of Henry Robb in this photograph sent in by one of the Shipwrights Barry Booth. Titled "The Swt Labes-Superb Guys"

"Shipyard Shuffle" – A way of walking from job to job in the yard carried out expertly by some men, a walk where you kind of dragged your feet along slowly.

This walk was of course never carried out at the end of a shift when the same “shuffle” would turn into a sprint which would leave some professional walkers in their wake.

"Dog" – A means of holding down steel plate, more and more dogs that are required the more distortion found in a plate usually due to poor welding sequence, and a sign of re-work needed and hence many more man hours to do a job that has not been dimensionally controlled.

"Rod Burner" A somewhat effectionate term for a welder (yea right) this was a term used for many welders when stick arc welding was the predominant form of the welding process in a shipyard, and while there were and are many very good welders in the shipyards, the other side of the coin was the "Rod Burner" enough said.

Wage Thief or collectivly known as Wage Thieves

A persom who goes into a shipyard (or other industry as there are many around)

and demands that he be paid for doing next to no work at all, very prevelant amongst lower management types and supervisors who know next to nothing about shipbuilding therefore cannot be expected to be able to do much work relating to said process.

Along with the above "Rod Burner" who would also fall into this catagory, people who go into a shipyard with the sole purpose of just lifting a wage at the end of the week/month, no real knowledge of the job and could not care less if the work was carried out well or if it was just another botched job to be hidden somewhere.


"Strake" – The name given to shell plates which were lettered from the keel up to the main deck so that Strake “A” would be the first shell plate adjacent to the keel and so on until you got to the “Bilge Strake” then the lettering would continue upwards.

"Knuckle" Where a plate changes angle or direction (create effectively a fold in a plate) a good way of reducing the amount of welding which is required, this method of plate work also reduces distortion when carried out properly.

"Bridge"A means of temporary connecting two plates together to be faired and welded.

 Datum Lines:- The use of Datum lines in shipbuilding is of
primary importance should you wish to build accurately and reduce re-work to a
minimum, believe it or not I have worked in some yards where they have not used
them for whatever reason and wondered why they could not build ships very well.
I hasten to add that the not using datum's changed once I got into the yard in
question, Mickey Mouse shipbuilders I shall call them. The positioning of said
datum's is also very important and should not just be positioned anywhere they
have to be positioned where they can be seen and not mixed up or taken
incorrectly along with any other markings for measurement purposes.

Datum lines used along with a modern Total Station linked
into a 3D measurement system such as Spazial Analyzer is a very good way of
ensuring accurate build along with a vast reduction in rework if used by
skilled men with shipbuilding experience. Another reason for using experienced
shipbuilders who know what the hell they are doing. It has become a pet hate of
mine the amount of cowboy shipbuilders around today who don't even understand
the "Basic Principles" of shipbuilding knowledge.

Almost as bad as allowing inexperience people to position
unit butts on the shell but that's another story.

Stealer Plate:- Used to take the place of a shell strake when getting close to the bow the "Stealer" will form one plate when not to use a "Stealer" would result in two shell strakes with too much "Bow" in them and also being too narrow the further forward the plate went.

 Dilutee:- Another word for diluted craftsman meaning someone who has not completed a recognised
shipbuilding apprenticeship or worse someone who has done one of them 1 or 2
year diluted courses then manages to secure a position an a shipyard.
Unfortunately for the industry nowadays some shipyards are full of them

Not someone recognised as a shipbuilder no matter how many
years they may have spent in shipyards.


Oxter Plate:- is a plate having double curvature, immediately below the transom floor
and running into the fore side of the stern post. This plate may often require shaping after
furnace heating it is usually of an "S" shape with curvature forward to aft and
a double curvature from bottom to top.


Frame Station:- Not to be confused with Frame Lines, the Frame Stations are set out by the Naval Architect when doing the original design of the vessel and they are equal spaced between the forward perpendicular and the after perpendicular so in a 100 metres ship you could have 10 Frame Stations which are used to create and lift the Scantling Offsets.

The Loftsman would then use the Scantling Offsets as a starting point to fairing the shell and hull creating the finished ships lines which were faired to the actual ships Frame Spacing which on a 100 metre ship would be perhaps every 600 mm with further frames going forward of the forward perpendicular and more going aft of the after perpendicular to create perhaps around 180 frames which would form the shape of the ship forward and aft and be shown as the Body Plan.

This would then form the finished "Faired Offsets" completly different from the limited information shown on a set of scantling offsets.

On smaller vessels or boats the Frame Stations are sometimes used in place of the Frame Spacing.

It is not really confusing and if you would like to know more about the subject of Lofting or Basic Shipbuilding Knowledge then look out for my soon to be announced courses which will be offered to anyone who has an interest and would like to further there understanding of Lofting and or Basic Shipbuilding Knowledge.

If you wish to find out more about this then please contact the website.  

Freeboard (Moulded) The difference between the moulded depth and the moulded draft. (It is the height of the side of the vessel which is above the water when she floats at her load water line)


DeadriseThe rise of bottom. It is the difference in height between the base line and the point where the straight line through the bottom flat surface intersects the vertical line through the side of the moulded surface at its widest point transversly


Coffin Plate:- the plate joining two side plates over the keel of a vessel at the stern which in plan view creates a shape similar to a coffin lid.

Counter stern:- a stern in which the hull above the waterline extends aft of the sternpost. Other terms, TRANSOM STERN, ELLIPTICAL STERN or ROUND STERN according to shape in the plan view.

Draught:- Distance from the bottom of the keel to the waterline. North Americans may spell and pronounce as "Draft".


Flam:- The falling outwards from the keel "convex" shape of the bow plates or flare out of the shell as the shape changes from an outer shape to an inner shape moving forward.


Dogging:- No not the term that has been somewhat hijacked to describe another even older human activity than shipbuilding.
This refers to the process of "Dogging" down a plate, a smaller plate with a shape cut out larger than the frame or beam that is to be dogged down is used, welded over the frame or beam, and the distance between the smaller cut-out plate and the beam or frame has a wedge driven in between to force or drive the frame down to meet the plate or shell that the frame is to be placed, there must be a perfect fit with no light showing through for the beam or frame to be welded to its mating part.


Pad Eye:- Not a posh Irishman but an aid to lifting steel, a welded triangular steel pad, radii at the top,  with a hole cut into it to accept a hook or wire strop. Depending on the weight being lifted determined the required thickness of the Pad Eye, or Lifting pad/Lug as also known.  This was of course before so called engineers made a career out of defining just how a lifting lug or pad eye should be designed.


To be continued.

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