Framing of the Gunports on 18th Century English Ships

[robcg]

Hello Everyone,

 

I'm hoping to get some advice regarding the gunport framing for an early 18th century English ship. 

 

Most deck plans that I've seen show the gunports perfectly perpendicular to the main axis of the ship, even afore and abaft, where the hull curves inwards towards the centerline.

 

Sheer plans, however, often show the foremost ports shortened in the fore and aft direction, as if they were set normal to the curvature of the hull, not perpendicular to the center axis.  Furthermore, having the ports angled in this manner would seem to work best with the cant frames in the fore and aft sections of the ship.

 

Does anyone have any info or reference to show whether the gunports were all set perpendicular to the center axis, or if they followed the curve of the hull in the fore and aft cant-framed sections?

 

Thanks,

 

Rob

[mtaylor]

Generally, on English ships, the gunport sides matched the frames (thus vertical) and the sills matched the sheer of the deck.   The catch is:  but not always. 

 

It might help if we knew which ship?

[NMBROOK]

This is a very good question Rob.Looking at Goodwin's book and pics of the builders model of Egmont(one of the few Navy board models with accurate framing),I am inclined to say that they follow the axis of the cant frames.Do remember though that the ports will appear shorter in the sheer plan as this is a side view,the hull is curving away from you.

 

Kind Regards

 

Nigel

[trippwj]

I haven't seen any contemporary documents that say other than square in shape aligned with the shape of the hull.

[testazyk]

Not sure what the exact formula is but Longridge says "Let us make the gun port lids first.  Most of them are square but a few of them at the bows have a slight tilt." 

 

I realize that is no help but it implies that some allowance was made for the curvature of the hull.

[HIPEXEC]

My plans said there're all the same regardless of position.

[testazyk]

Yes, Rich, I did some looking around and can't find anything that supports different shapes.  Maybe by tilt Longridge meant allowance for sheer?

[robcg]

I think Longridge is, indeed, speaking of the tilt imparted by the sheer of the deck.

 

Wayne, if you've got something which indicates that the ports are to be "aligned with the shape of the hull", that would probably be what I'm looking for.  It matches Nigel's explanation of ports following the axis of the cant frames, which seems to me to make the most sense.  If you can let me know where you got that info, I'd appreciate it.

 

Rob

[trippwj]

Good morning, Rob.  Let me do some digging - I know that the documents I looked at all refer to square ports (a single dimension given for the size inside the port fore & aft and a single dimension up & down).  The plans also show them following the external hull shape with a square opening.  The port size is different for each size gun but still listed as square (sources include Humphreys, Rees, Sutherland and a couple of others). 

 

Here are a few older pictures of the Connie (1858, 1874 and 1905) where you can see the square ports follow the expernal hull shape.

 

1858

 

 

1874

 

 

1905 as a barracks ship.

 

[robcg]

Thanks Wayne, I greatly appreciate your help!  I've attached some photos of the plans that have caused this problem for me...

 

 

The first is from Plate II of Steel, and shows the second gunport on the gundeck is clearly framed by cant frames.

 

 

The second photo is from Plate 5, and shows that the port is cut perfectly perpendicular to the center axis of the ship, cutting through the cant frames instead of lying on the same axis with them. 

 

This seemed odd to me, and has been causing me some grief as I try to finish a disposition of frame plan for a ship of the 1719 Establishment.  If Sutherland wrote something on the topic, I completely missed it.  Clearly I'll have to go over my notes again!

 

Cheers,

 

Rob

[trippwj]

Top of the morning, Rob.  Interesting observation - although Steel is quite some distance (time wise) removed from the 1719 Establishment.

 

Looking at Sutherland is always an adventure!  Have you seen the 1993 article in The Northern Mariner by Tevor Kenchington - The Structures of English Wooden Ships: William Sutherland's Ship, circa 1710?  http://www.cnrs-scrn.org/northern_mariner/indices/index_vol_3_e.html

 

It is a very interesting read as he moves through reconstructing the ship based on Sutherland and contrasting with contemporary ships and later practice.  For example, see the figure below from his paper:

 

 

I need to do some digging through some of my transcriptions of Humphreys notes, but there was one circular concerning altering the frames in the way of some of the gunports on the frigates.  Will see if I can find that and post it when I get a moment.

 

So, having said all that, I really am not sure how to take the framing as drawn by Steel.  On the one hand, it would seem to indicate that at least a couple of ports were cut on the bias to the frames - which would indicate potential weakening of the frame.  It would also then appear to indicate the desired angle for the gun as being directed less forward (the orientation of the port opening) - keeping the gun nicely aligned with the rest. 

 

On the other hand, looking at Rees' Plates II and  III (I believe they are the same as Steel's), it doesn't appear that the frame timber is reduced in the way of the port.  Very strange!

 

Let me see if I can find the information from Humphreys and will post it later today.

 

Thanks for asking these questions - it is an interesting exercise not only in design but also geometry!!!!!

 

[allanyed]

Rob,

If you find a framing disposition plan earlier than about 1760 please let us know.  I have been researching like crazy circa 1719-1745 and have found none.  The only thing remotely close is the fully framed model from 1715-1717 that shows all square frames on one side, and use of cant frames on the other side.

 

Franklin has a lot of photos of this model in his book and the NMM site has several. http://collections.rmg.co.uk/collections/objects/66366.html

 

Allan

[trippwj]

Allan -

 

Have you seen these from Sutherland (1711) - The ship-builders assistant : or, some essays towards compleating the art of marine architecture

 

online at http://echo.mpiwg-berlin.mpg.de/ECHOdocuView?mode=imagepath&url=/permanent/library/AE4UUGBR/pageimg

 

 

 

 

 

Not sure if they are as detailed as others, but they are an early view of some of the framing.

[allanyed]

Thank you very much Wayne, I had not seen those and appreciate you posting.  Alas, I am looking for drawings with cant framing in the disposition drawing and a bit more detail..  The drawings I am used to seeing show offsets and canting of the various futtocks around gun ports, sweep ports, etc.  Sutherland is pretty basic, not unlike the majority of framing on the contemporary dockyard models. I wonder if  the Sutherland drawing is supposed to be more suggestive than actual.  Some of the gun ports do not meet the framing on both sides and others show half the siding of a frame cut away to allow the gun port in place. 

 

Two examples of dispostion drawings from the National Maritime Museum Collections website are attached, a 74 from 1763, and a 50, the drawing of which is from 1776.  Sorry to be so picky.  I really do appreciate your taking the time to post your response. 

 

Allan

[robcg]

Allan,

I'd agree that Sutherland's plates are more like suggestive illustrations than technical draughts, and should be used with caution.  Sutherland's text (pg.35,38,39) makes very clear that the frames should be used at, or near, the sides of the ports and that the principal frames must never be cut by the ports - in direct contrast to the illustration.  There are a few other examples of his text and his plates being somewhat contradictory, with the plates being the less reliable.  It may be of interest to you that Sutherland's text (pg.35) explicitly mentions the use of cant frames in the bow, but he never mentions cant frames in the aft section of the hull. Plate 38, above, is drawn accordingly.  Perhaps cant frames in ship's bows were introduced prior to 1711, and followed by the inclusion of aft cant frames sometime between 1711 and the construction of SLR0405 in 1715ish?

 

Wayne,

Thanks so much for your post.  I had not seen the Northern Mariner article, and now I've got some weekend reading ahead of me.  You're correct that Steel is a bit removed from the 1719 Establishment!  Since Sutherland is not always as detailed as I'd like him to be, I've been forced to occasionally interpolate from Steel, Mungo Murray, or Anthony Deane.  I greatly appreciate your help on this issue!

 

Cheers,

Rob