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Query for Knowledge: Elm (Tree) Pumps?


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Hi All,

 

I've been wondering about Elm Pumps.   Usually sitting right next to the chain pumps (who's function IS clear to me), I'm not understanding what they are pumping.  Just another way to pump the bilge?  Or something else?   Why are they called Elm, and sometimes Elm Tree pumps, and which is correct?  Are they made from Elm trees?  :)

 

 

Rick

                        

Current Build: MS Mayflower II

Completed: MS USF EssexMS USS Constitution Cross SectionMS 18th Century Armed Longboat  

 

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Hi Rick,

 

Elm Tree Pumps, also known as the common or brake pump were multifunctional.  In a ship with chain pumps the Elm Tree Pump served to bring fresh seawater up for washing the decks and feeding the condenser on the stove.  They could provide water for fire fighting on deck but they were only a lift pump and not a pressurised pump so couldn’t be directed at a fire as there was no head of water (ships had separate fire engines / pumps that could generate pressure and be directed at sails etc.)

 

Initially the pump casing was open directly to the sea through the ships bottom, but in the late 18th Century they were brought inboard and a system of indirect pipe work via valves and stop cocks could let sea water in to the cistern around the mainmast and the foot of the pump was now inside the ship within the cistern to lift the water.

 

In smaller ships without chain pumps the elm tree pump was the primary means of clearing water from the hold.

 

They are called Elm Tree Pumps as it was the bored trunk of an elm tree that was used for the pump casing.

 

Gary

Edited by Morgan
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11 hours ago, rlwhitt said:

I hadn’t considered drawing up fresh water.

Whatever water was in the bilge which could be fresh from rain water mixed in with the normal sea water that was found in the bilges. Certainly not fresh drinking water.

Allan

PLEASE take 30 SECONDS and sign up for the epic Nelson/Trafalgar project if you would like to see it made into a TV series.   Click on http://trafalgar.tv   There is no cost other than the 30 seconds of your time.  THANK YOU

 

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2 hours ago, allanyed said:

Whatever water was in the bilge which could be fresh from rain water mixed in with the normal sea water that was found in the bilges. Certainly not fresh drinking water.

Allan

 

Right, I guess I could have clarified - non bilge water 

Rick

                        

Current Build: MS Mayflower II

Completed: MS USF EssexMS USS Constitution Cross SectionMS 18th Century Armed Longboat  

 

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Hi Rick

Goodwin describes these as being the main bilge pump on fourth rates and below.  On larger rates they were used for taking water from holes in the hull or from cisterns.  The Construction and Fitting of English Ships of War, page 142.  I have no idea how they were employed on American ships.

Allan

Edited by allanyed

PLEASE take 30 SECONDS and sign up for the epic Nelson/Trafalgar project if you would like to see it made into a TV series.   Click on http://trafalgar.tv   There is no cost other than the 30 seconds of your time.  THANK YOU

 

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Two examples,

On the left 1 tap at the hull to let water drain into the well to then be pumped out.

On the right 2 taps one at the hull and one at the base of the pump, this allows you to do the same as above or to pump from outboard without filling the well.

 

ZAZ6944j2288.jpg.5d72a605f7eb166d83c47dbff35cd4a9.jpg

Craig.

 

I do know, that I don't know, a whole lot more, than I do know.

 

Current Build: 1:16 Bounty Launch Scratch build.   1:16 Kitty -18 Foot Racing Sloop   1:50 Le Renard   HM Cutter Lapwing 1816  Lapwing Drawings

Completed....: 1:16 16' Cutter Scratch build.

Discussion....: Bounty Boats Facts

 

 

 

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Craig, what is the ZAZ number on the bottom left, I cannot make it out?

 

THANK YOU

 

Allan

PLEASE take 30 SECONDS and sign up for the epic Nelson/Trafalgar project if you would like to see it made into a TV series.   Click on http://trafalgar.tv   There is no cost other than the 30 seconds of your time.  THANK YOU

 

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6 minutes ago, allanyed said:

what is the ZAZ number on the bottom left

6844  https://www.rmg.co.uk/collections/objects/rmgc-object-86635

 

Craig.

 

I do know, that I don't know, a whole lot more, than I do know.

 

Current Build: 1:16 Bounty Launch Scratch build.   1:16 Kitty -18 Foot Racing Sloop   1:50 Le Renard   HM Cutter Lapwing 1816  Lapwing Drawings

Completed....: 1:16 16' Cutter Scratch build.

Discussion....: Bounty Boats Facts

 

 

 

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10 hours ago, iMustBeCrazy said:

THANK YOU!!!

 

Allan

PLEASE take 30 SECONDS and sign up for the epic Nelson/Trafalgar project if you would like to see it made into a TV series.   Click on http://trafalgar.tv   There is no cost other than the 30 seconds of your time.  THANK YOU

 

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7 minutes ago, allanyed said:

THANK YOU!!!

No worries ;)

 

Craig.

 

I do know, that I don't know, a whole lot more, than I do know.

 

Current Build: 1:16 Bounty Launch Scratch build.   1:16 Kitty -18 Foot Racing Sloop   1:50 Le Renard   HM Cutter Lapwing 1816  Lapwing Drawings

Completed....: 1:16 16' Cutter Scratch build.

Discussion....: Bounty Boats Facts

 

 

 

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