HMS Bellona 1760 by SJSoane - Scale 1:64 - English 74-gun - as designed

[SJSoane]

Now for some analysis of geometry and construction. 

 

Fifteen years ago, I built the stern frame based on my observation of the first Bellona model, and the Admiralty drawings. I did not understand what I was building at the time, I just followed what I saw. And now I understand as I get into the details.

 

In the model, you can see a couple of strange things. first, the tops of counter timbers with the dovetail joints stand proud of the horizontal transom tying them together. This leaves a gap of about 2". I now realize that these gaps provide a space for the bank of sash windows to slide up into. It means that the windows can be opened at the bottom by about 9"; not a lot, but better than no opening!

 

Second, the side counter timbers, effectively the end of the hull frame, project out from the bottom of the balcony upwards. that is, the bank of windows are recessed back relative to the balcony, creating a shadow line between the upper and lower parts of the stern. There is no functional reason I can see here; it is a visual trick to emphasize the sweeping serpentine curve of the balcony from one side of the composition to the other.

That creates some complication in how this is constructed. The green line shows the aft most edge of the side counter timbers, or hull. There is one moulding along the tops of the window bank, just under the balcony, in red below. Another moulding runs along the base of the balcony, in orange below.

 

 

when the balcony swings out from the stern, the two mouldings split from each other:

 

The next item I did not fully appreciate until I started constructing the stern is how its design needs to reconcile  two geometries working against each other; the upper sweep of the sheer, and the flatter sweep up of the decks (red lines below). The conflict shows a little where the gun ports cut into the sheer in odd places.

But at the stern they really need to be resolved. One of the most important, I discovered, is that the moulding at the tops of the windows must align with the sheer of the deck at its upper edge (orange line below), since it sits flush under the deck itself; but its lower edge must conform to the sheer of the hull (dotted red line below), since it turns the corner and runs along the side of the quarter galleries that align with the hull's sheer.

 

And then one more thing about the stern. In 2014, ten years ago, I posted a question about the stern geometry (posting #173). I noticed a discrepancy in the drawings relative to the roundup of the quarterdeck. If I continued the deck aft with its normal roundup, it was a couple of inches lower than the deck as it was shown coming out into the balcony. There was a lot of discussion around posting 173 as to whether this was a mistake in the drawing, or something else. I finally found in Steel that the quarterdeck does indeed increase its roundup as it approaches the stern balcony, to give a lighter, more springy feeling to the visual lines of the stern. So the drawing is correct, and this needs to be accounted for:

 

 

So, construction next!

 

Mark

 

Edited March 2 by SJSoane