Nate's PANDORA in 3D

[druxey]

Whew! Quite the exchange of ideas and views, to which I can add but little. All I can say is that there are several contemporary models in frame that should also be seriously considered.

[Pirate adam]

On 12/1/2025 at 6:41 PM, 3DShipWright said:

If I may ask, what discrepancies are you referring to?

Nate,

 

The first thing that I came across was the number of transoms.  The Anatomy of the Ship book shows 5 transoms.  My shear plan of Crocodile shows 4 transoms.  All of the other Porcupine class ship drawings I have seen also show 4 transoms.  This is consistent with my interpretation of the tables in Shipbuilders Repository.  The other point was the big difference between the various disposition of frames drawings I could find for ships in the class. The disposition of frames drawings for the Porcupine class do clearly show the diminishing timbers.  I made the assumption based on the disposition of frame drawings that the frame bends had air spaces separated by chocks vs the Anatomy of the Ship book which shows the bends as adjoining frames.

 

I will add this is a very interesting discussion.  I don't have much to add in terms of debate.  I am surely not an expert in naval architecture.  It is clear we both started with a different set of assumptions going in which results in a different result in the end.  As I said in my original post the fact is no one knows for sure.  The most important thing is your 3d model is awesome, and I really enjoy every post.

 

Adam

[3DShipWright]

@Pirate adam

Thanks Adam,

I too agree that the transoms in the AoTS book are somewhat incorrect, albeit for a different reason than the one you provided, which I shall address first:

On 12/2/2025 at 8:32 PM, Pirate adam said:

The first thing that I came across was the number of transoms.  The Anatomy of the Ship book shows 5 transoms.  My shear plan of Crocodile shows 4 transoms.  All of the other Porcupine class ship drawings I have seen also show 4 transoms.  This is consistent with my interpretation of the tables in Shipbuilders Repository.

 

First, let me state that you are correct - a 24-gun ship has four transoms. Sixth-rates and below have no transoms below the Deck Transom, meaning the Deck Transom rests directly upon the fashion piece and any filling cant frames. Above the Deck Transom there are one or more Filling Transoms (I'll come back to this in a moment) and finally, the Wing Transom.

 

However, depending upon the class of ship and the Deck Transom's relative position to the Gun Deck - which refers to the lower deck in Pandora's and Crocodile's case despite there being no guns - the Deck Transom may need to be split.

 

(The image below is of the HMS Eurydice of 1781. HMS Eurydice was cited in the AoTS book as the source material for Pandora's framing profile.)

 

BTW - In case you're wondering why the admiralty plans depict the wing and filling transoms pointing at different angles, it's because the draftsman is trying to depict the sweep of the transoms outward as they curve to follow the crossfall of the deck (shown with how the Wing Transom was drawn), as well as what the centerline of the transoms look like (shown with how the Filling Transoms were drawn), or both (shown with how the Deck Transom was drawn, which is why it is drawn as a wedge shape).

 

In summary, there are four transoms, but because the gun/lower deck bisects the deck transom, there are technically five transom pieces. Bear in mind this is merely my interpretation, but it seems to fit with all available data.

 

 

Lastly, as said, I did have a few problems with how they did the transoms for Pandora. I'll be back in another post soon to share that part and get your thoughts.

 

Best,

-N.

[Kenchington]

28 minutes ago, 3DShipWright said:

why the admiralty plans depict the wing and filling transoms pointing at different angles

I would put it rather differently: The upper and lower surfaces of the intermediate ("filling") transoms would be parallel to the baseline (i.e. the keel). In contrast, the upper face of the deck transom has to match the camber and sheer of the deck, while the wing transom has to curve in harmony with all of the stern structure erected above it. The draught represents those shapes in orthogonal view.

 

More generally, I think we need to bear four different things in mind.

 

First are the general concepts of ship structures in use at a particular time and place, for hulls of a particular size and intended purpose. Understanding those needs study of textbooks, draughts and models, matched by a lot of thought.

 

Next up are the specifics of a particular ship, as intended when her draught was laid down. If that draught or a model survives, well and good. If not, we have to fall back on interpretation from the general concepts (which can often guide interpretation of specific evidence too).

 

Third, there is the ship as she was when launched. Steel plate and sections can be ordered to specifications, but trees come in the shapes and sizes that individuals have grown. When a shipwright picked through the  pieces on hand and found a crook ideally shaped for a particular floor but a bit wider in siding than the draught called for, the excess wasn't usually trimmed off with an adze and wasted. Rather, that floor would be fitted a bit wider than intended, allowing a thinner and more economical piece somewhere else -- maybe the adjoining futtock of the next floor. Doubtless, the deviations from intentions were less in the royal dockyards than in outlying yards building fishing craft. But the draughts could not be exactly followed without a lot of waste of good (expensive) timber.

 

Finally, there is the hull as it was at some later point in time, with all of the damage and repair that had gone on in the interim. That is not usually of much concern to model builders but it does matter very much when archaeologists examine wreck remains -- which feeds back to model building in cases (like Pandora) where the information available is partly drawn from archaeology.

 

And so we come back to the choices of the model builder: Go for idealized generalities, a tidy representation of specific intentions or a realistic representation of messy reality? There is no one right choice!

 

Trevor

[Waldemar]

 

4 hours ago, Kenchington said:

More generally, I think we need to bear four different things in mind [...].

 

A nice summary, or as a scholar would say, a synthesis of the issue...