? Cable Compressor

[barkeater]

This is a view of the upper deck or gun deck Unite 1796 refit. The paired rounded structures aft and forward of the main mast looking at the side view (not uploaded) are chain pumps and elm pumps respectively adjacent to the main mast. My question is what is the unpaired octagonal structure. This is not shown on the lateral as the pumps are. It is also indicated on the lower deck in the floor plan but also not the lateral view. It could be for the cable compressor however this was usually situated on the undersurface of the main hatch. The quarterdeck shows paired scuttles above it and the shot locker would be adjacent to it on the orlop deck. Could it be a pass through for shot up through the lower and upper decks? I doubt it but I just can't figure it out with a degree of certainty as to what it represents on the plans. Ideas?

[popeye2sea]

Could it be an octagonal shaped deck prism to allow light through to the lower deck?

 

Regards,

[Morgan]

Certainly for British service as Surprise L’Unite was fitted with 4 chain pumps, 2 pair either side of the mainmast, the other feature is an Elm Tree or Brake pump.  The book ‘The Frigate Surprise’ by Brian Lavery and Geoff Hunt show this in drawings provided by Karl Heinz Marquardt (they actually have 2 Elm Tree Pumps), you can also see it in the photo below which is from Caldercrafts long awaited prototype photos for the Surprise.

 

The drawings you are using don’t show all details, so you can’t rely on something not being there, there is a large degree of variability in Admiralty draughts in what they do and don’t show.

 

Gary

 

 

Edited February 4, 2021 by Morgan

[barkeater]

The 38 gun Unite 1796 refit which I'm building was not the Surprise. She was taken as the L'Unite' and renamed Unite' after the refit. She was briefly commanded by Nelson in 1801. The plans clearly show that the pumps fore and aft the mainmast are of distinctly different types with the forward pumps being elm pumps and those aft chain pumps. I'm still lefty with the unpaired structure. It would be odd to have an unpaired chain pump or elm pump. Also the picture above of the Surprise shows carronades and on the gun deck. The Unite' carried 12 pounders on her gun deck. She did carry 4 32 pound carronades but this was on the forecastle.

[dafi]

My understanding too is that the single one  is the elm tree pump. Often they were fashioned in this octagonal shape, with the hole in the middle. They served as fresh water pumps for multiple purposes.

 

If I can distinguish properly, one of the plans show the Unite with the 4 french pumps that were single wooden tubes with a metal joint in the middle. 

 ZAZ3181 https://collections.rmg.co.uk/collections/objects/82972.html

 

The decks plan fits to this 

ZAZ3183 https://collections.rmg.co.uk/collections/objects/82974.html

 

The deck plan is in this sense strange, as this pump would be to near the bit. Also the fore and aft hols are shown different.

ZAZ3184 https://collections.rmg.co.uk/collections/objects/82975.html

 

This side elevation shows a different pump than usual and a curved pillar. Could this be a hint. I can´t distinguish the front one due to the resolution:

ZAZ3182 https://collections.rmg.co.uk/collections/objects/82973.html

XXXDAn

 

 

Edited February 5, 2021 by dafi

[barkeater]

Thank you for all your replies. The paired pumps on the side view "as refit" are different for and aft compared to one another and are different from the drawings "as taken". The "as taken" pumps are identical to one another. The unpaired  one is seen only on the "as fit" deck plans. Instead of a chain pump or elm tree pump for draining the well, I think it is a hand pump for deck cleaning fed from a cistern. The following is from Lavery in "Arming and Fitting of English Ships of War 1600-1815"

 

" A new system of supplying water for washing decks was introduced in 1770. The dockyards were ordered to 'fix a cistern in the well on board all three- and two=decked ships building, repairing and refitting" 

The cistern was fed with clean sea water from both sides of the vessel via copper pipe ensuring water to draw from if the ship was under sail and heeling over. The time frame fits as does the unpaired configuration. I'm going with it. Thanks again to all.