Drafting Frames

[tmj]

If the 'Body Plan' offers the exterior geometry of the stations, how does one go about acquiring the 'interior' geometry for those stations? I know that this is a really basic thing for you experienced folks, but I'm stumped!  

[Mark P]

Good Evening tmj;

 

Assuming that you are speaking of Royal Navy ships, or similar, even for experienced folk it is not really basic, unfortunately. With some exception, the inner line of the timbers at each station is a gradual taper from the thickest dimension over the keel, to the thinnest at the capping rail of the ship's side. To draw the timbers successfully, it is necessary to know the thicknesses and the points at which they were measured. This knowledge can be gained only from study, of either contemporary or modern books, or the sources on which they are based. 

 

Allan Yedlinsky's book 'Scantlings of the Royal Navy', gives a good start in this field, but it will not be a quick learning process. You will need either a level of dedication bordering on the masochistic, or a very determined interest in mastering the particulars. However, once grasped, the principles will remain with you, and the only additions are the particular dimensions for each size or type of ship. It is a rewarding study. 

 

Did I say anything about the additionally necessary knowledge of the 'horizontal' timbers which tie all these stations together; which also have their own idiosyncrasies and behaviour: keel, keelson, clamps, wales, spirketting, to name the principal ones. 🙂 

 

All the best,

 

Mark P

Edited November 23, 2023 by Mark P

[tmj]

Thanks Mark. Unfortunately, the ship in question is the Continental Frigate 'Hancock' (captured) aka the 'Iris'. There doesn't seem to be much data out there, for this vessel, other than RMG's plans.   

[druxey]

Scantlings will be a good guide for any ship of the same size and period. Allan's book is an invaluable source for measurements.

[Jaager]

The Continental shipbuilders were English shipbuilders until they decided not to be.  They used the same books and same Establishments.

The properties of wood is a constant.  The ratio of the size of the timbering to the size of the ship is not a national value.  The species of wood used can be.  There are tables that have different sizes for timbers depending of the species of wood used.  Try not to obsess  about being exact.  Close enough is good enough.  It was wood.  They did not have sophisticated electronic rulers. 

I use Yedlinsky .   Find the ship's class and look up the scantlings.

I find that the Admiralty plans for captured ships are often fairly useless for determining R&S.  The stations are often arbitrary in location and distance.

Some of them are at variable locations.

With as designed plans,  The tables give floor thickness.  The lettering and numbering of the stations reflect the number of frames between each station.

The difference is the width of the space.

As for the moulded dimension,  tables from this era give minimal data for in and out.   You have to look closely.  Use what data there is and use an artist's eye to get the shape.  

I translate cutting down to be the thickness (deep) at the outer edge of the keel/keelson.

When I used a drawing board,  I used a compass to draw a half circle with the origin in the frame line.  A line that hits these arcs at a tangent is the moulded dimension.  Tedious at best.   Painter is easier.  Now I have a file with the range of frame moulded values - each value is a yellow filled circle that is the diameter - a faint black circumference helps -  on its own layer. 

Just kiss the frame line and connect the tangents on the inside.  I use as many as I need to get a line that looks good. Layers are easy to duplicate.  It is quick after some practice.

 

 

 

[allanyed]

11 hours ago, Jaager said:

The Continental shipbuilders were English shipbuilders until they decided not to be. 

That is the best line I have ever heard regarding our shipbuilding forefathers.

Allan

Edited November 24, 2023 by allanyed