Sided in the bearing of the Ship

[Don Case]

I'm looking at  Steel's and under floor timbers the dimension is "sided in the bearing of the ship".  What is "bearing" referring to? Thanks

Edited February 11, 2021 by Don Case
clarity

[Jaager]

Using 3D CG orientation:

Body Plan   the baseline as X   the vertical as Y

Profile Plan  the vertical as Y   the length as Z

"bearing of the ship"  would be the Z

 

This is how wide the floor timbers are when viewed from the side.  It is also the "sided dimension".

It is mostly an English characteristic that each subsequent futtock (F) has a sided dimension that is less than the one below it.

Floor >/= F1 > F2 > F3 > F4 > Top  This is dependent on the time period. 

In France and North America  Floor = F1 = F2 = F3 = F4 ~/> Top  is common enough to be treated as standard.

 

Another dimension is the moulded.  

I treat "cutting down" as being at the outer edge of the keelson.

Head of the floor is outer end.  Heel of F1 is the end closest to the keel.  In Steel I think it is head of F1 / F2 / F3 / F4 / etc.

 F1 overlap of F2 tells you how much beyond the Floor F1 goes.  F2 overlap of F3 tells you low long F2 is when you add F1 overlap.

 

The length of F1 depends.  In France and NA a Half Floor was commonly used.  It was one half (or a bit less) the length of the Floor.  This makes F1 shorter, more manageable, and removes a source of weakness at the midline.  The English used a HF, or a smaller Cross Piece, or a giant Cross Chock.  Almost never did F1 port butt 100% heel to heel with F1 starboard.    

 

Edited February 11, 2021 by Jaager

[Mark P]

 

Good Evening Don;

 

The literal meaning of the 'bearing of the ship' is as follows, and comes from the good old days when ships were careened regularly to have their bottoms 'breamed', which is burnt, scraped and re-sealed with whatever composition was needed/available. 

 

When ships were careened, they were tilted over sideways on a hard piece of the shore. The part of the ship's hull which was in contact with the ground, and 'bore' the weight of the ship was the turn of the bilge. This part of the hull was indeed, as Jaager says, where the floor timbers ended, with an upward curve. So the sided dimension at the bearing is the fore and aft thickness of the outer ends of the floor timbers.

 

The 'bearing' of the ship ends where the floor timbers cease to have a flat component to their central geometry, and start to become more 'V' shaped, both fore and aft. 

 

All the best,

 

Mark P

[Don Case]

Thank you. What about the depth of the floor timbers? The drawings in Longridge show the floor timbers as being thicker than they are wide but I can't find a dimension that would reflect that.

[Don Case]

I was looking in the Oxford glossary and it is saying(I think) that the "moulded" dimension is the dimension that a pattern or "mould" would indicate. So if you make a pattern of a frame it can only show two dimensions, length and depth. Does that sound right?

I still can't find it in the scantlings sheet. 

[druxey]

Moulded dimension (or the moulding way) is measured across the face of a curved timber. Sided dimension is its thickness. Usually the latter is constant in dimension.

[Jaager]

If you are going to do much of this  it would serve you well to get a copy of Yedlinsky -- it is easier to read  as well as covering the 18th century for the RN. 

 

For a sloop 18 gun   11"  minimum "below the cutting down in Midships"  "and forward and aft to increase with the rising"

the siding is also 11"    Floor at head 7.5"  

fine print in Steele    -

 

Victory is a first rate  - a whole nuther animal as far as scantlings   Longridge is about Victory. 

The physical characteristics of wood as a material for the construction of hulls has an upper limit beyond which a hull cannot sustain the stresses.

A first rate is at the cutting edge of that limit.  A sloop is not. 

What with the ridiculously heavy weapons being carried perilously close to being above the metacenter and the length making Z axis integrity difficult - thick  was needed - as well as extras - like riders.  A sloop would not be a scaled down first rate.

 

[Don Case]

Yedlinski is too expensive for me. It would be about $70Can with freight and exchange. I was looking in Steel at the "fine print", italics in mine, and I had more or less convinced myself that that must be the depth but Longridge's pictures confused me a bit. I'll keep that in mind. I'm finding that Steel's glossary and the Oxford glossary help a lot. I'll try not to be a nuisance🙂

[Don Case]

23 minutes ago, druxey said:

Moulded dimension (or the moulding way) is measured across the face of a curved timber. Sided dimension is its thickness. Usually the latter is constant in dimension.

That would go with my way of thinking but I like your definition better🙂 Thanks

[Mark P]

Good Evening Don;

 

I assume from your reference to Steel that you are looking at a ship from the Royal Navy in the later 18th century. 

 

Most tables of scantlings, or contracts, give a dimension for floor timbers 'on the keel', which is measuring upwards from the top of the keel. Depending upon the period in question, this will actually be measured upwards from the top of the hog, or rising wood, which is a length of timber laid on top of the keel to make it easier to form the 'deadrise'. This latter is the gently sloping part of the ship's bottom, starting immediately on each side of the keel, which is sometimes a straight line, but often a shallow curve, sometimes combined with a straight line. The amount of deadrise is normally specified in a contract, and is measured from the top of rabbet for the garboard plank in the keel, to the underside of the floor timber where it crosses the keel (or hog if fitted) Although models usually have floor timbers made in one horizontal piece, with the bottom tapering downwards towards the keel, in full-size practice it was normal for the floor timber to have its top and bottom parallel for most of its length, and to fit a triangular 'chock' under the floor timber on each side, which ran into the side of the rising wood. 

 

The whole subject of structure is rather complex, and has its own specific vocabulary. To make it more complicated, the method of building the structure changed regularly; for example what was applicable in 1700 will be radically different by 1750. There are a few books around which will help to understand this, but none of them really cover the subject in its fullest extent, unfortunately. 

 

There were a series of articles by David White in Model Shipwright, around issues 45 -60, which covered this subject in the fullest manner of which I am aware. Unfortunately, this was never completed in its entirety. If you really want to know the subject in depth, it will take some serious study, and require a fair bit of digging for sources. If you want to understand what is best from a modelling point of view, then the series of excellent 'Swan' practicums by David Antscherl will give a wonderful grounding in the subject. Unfortunately, their level of quality is not cheap to purchase, and this may be not possible at present for you. Volume I would do the job of understanding the hull structure for you, if you can stretch to it. They do occasionally show up here second hand. The structure shown in this is relevant to the larger part of the later 18th century.

 

All the best,

 

Mark P

Edited February 12, 2021 by Mark P

[Don Case]

Thank you Mark. Gradually the vocabulary is coming. Deadrise sounded familiar but it wasn't until the second read that it popped into my head. I just read about chocks this afternoon. 

A question about something related to deadrise is what I would call "rocker". Fore and aft "deadrise". If indeed one of these ships had any rocker would they get it with deadwood(hog, rising wood) that tapered toward the center.

[Mark P]

Good Evening Don;

 

To the best of my knowledge, the keel was laid straight, and the hog was laid on top with an equal height for its own full length. I have not seen anything to indicate otherwise. Which is not to say that it was not done, but I am not aware of it. The heavy timbers of the various wales, with their exaggeratedly curved 'sheer' were intended to counteract the tendency of the ship's ends to droop, and I doubt that building a small amount of curve along the keel would achieve much; bearing in mind that ships were also subject to the opposite stress, with the centre of the hull sagging downwards when passing over the trough between two large waves, so that there is good reason to avoid building in a pre-formed 'sag'. Incidentally, deadwood is not the same as rising wood; at least not as it is generally accepted/used. Rising wood (hog) is located under the straight floors, stretching fore and aft from midships. Deadwood starts where the rising wood ends, and is used at the extremities, bow and stern. The deadwood is built up in layers to form a base for the half-timbers and 'V' shaped, made floors (also called hooks) However, you will come across deadwood and rising wood used interchangeably in some modern works, and even some contemporary documents, so the definition is not completely clear-cut. 

 

Also, chock covers a multitude of uses, sizes and shapes. For example, there are chocks which are completely parallel-sided; polygonal chocks to join the futtocks; and triangle-based chocks in the floor timbers and transoms, amongst others.

 

More to think about!

 

All the best,

 

Mark P

[Dr PR]

Don,

 

Curvature along the center line length of the ship at the deck level is called "sheer." Typically the bow is higher than midships, and sometimes the stern is higher than midships.

 

The curve at the deck from side to side is called "camber."

 

A ship's keel was straight when the ship was new, but the bow and stern tended to sag with time, especially on wooden ships. This is because the lift from flotation is proportional to the cross section (side to side) area of the hull. The narrow bow and stern did not have as much lift as the wider midships section. This curvature with drooping bow and stern is called "hogging."

 

If the bow and stern bend upward relative to midships it is called "sagging." Long ships experience some hogging and sagging as they ride over large waves and into the trough between waves.

 

[allanyed]

Don, To confuse things even more, the curve of the deck beams in the scantlings of The Elements of Naval Architecture (Steel), the Shipbuilder's Repository, individual contracts, and the Establishments  is called rounding, round up or is said "to round "  rather than camber which I believe are pretty much the same thing.  I have not seen any of these contemporary sources use the word camber , so if you are looking for the value look for round or rounding.  These sources give the rounding for each deck which varied from deck to deck as well as rate to rate.

 

Allan

[Don Case]

Thanks guys. When I was designing ang building IOM's we would put "rocker" in a boat for more maneuverability. It was much the same a sag but deliberate. I just assumed that they may do the same thing.

 

My Oxford glossary lumps the three (deadwood, rising wood and hog) together but does have the arrows pointing to different spots🙂