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I have some questions regarding chain pumps. Apparently these are the most appropriate pumps for my Byzantine dromon (as remnants were found on the contemporary Byzantine  Serce Limani wreck). As I'd never heard of chain pumps before this week, I've done a search through previous posts and they've cleared up the worst of my iggerance, but I still have a few questions.


* In the models I've seen, chain pumps always seem to come in pairs - a port and a starboard one. Was this always the case? There were never any single chain pumps?

* In all the pictures and models I've seen the pumps seem to be cut off at the outlet (the dale?). Am I right in thinking this leads to scuppers via a pipe or hose?

* The dromon only has one deck; the upper deck (if you ignore a little poop deck). So would the pumps and dales be on this upper deck?

* In an earlier thread which dealt with chain pumps

Druxey replied

Chain pumps usually are sited a few feet aft of the main mast, the elmtree pumps a few feet forward of it.


I realise this is a very different kind of ship from a completely different time and culture and I do have the Serce Limani ship still to check, but lacking surviving evidence to the contrary, would I be safe enough putting the chain pumps "a few feet aft of the main mast"?


Any help with these questions would be gratefully received.



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One reason for pumps to be in pairs (one to each side) is that the ship is often heeling to one side or the other so the effectiveness of the pump on the leeward side is greater.


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And the keel would be in between stopping the water getting from side to side, so two would be more efficient


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Thanks for the replies. That helps clear a few things up.


Just to clarify, the top of the pump mechanism (the top wheels and the handles) would be on the upper deck itself? (I think I've already answered this, but I'd like to make sure.)


And regarding the dales, a pipe or hose across the upper deck leading to a scupper on each side?


Thanks again.



Edited by Louie da fly
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Another question - does anyone know how big the top cogwheels of the chain pump were/should be?


Is there a sort of standard size, or does it vary with the size of ship?


And if it varies, how big should they be for a dromon - a ship 30 metres (90 feet) long that is long and narrow?


Rough estimates totally acceptable. I just want to get an idea of the size I should be looking at for my chain pumps, because currently I have no idea at all except for trying to estimate it from looking at pictures of them on models.


Thanks in advance,



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Would it not be depend on the size of the links and their ability to be turned over the wheel without too much mechanical disadvantage? An 18th century wheel was 24" in diameter, the links 7" between pivot points and the crank throw was about 15". However, several men at a time turned the cranks.

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Thanks, Druxey. I was really just after a ball-park sort of figure, and what you've provided is very helpful.


The TAMU paper I have contains some archaeological finds of links which I'll also have another look at, though if I remember correctly they're from several centuries too late. Still, any information that helps me to a decision is worthwhile.


A dromon with a crew of over 100 shouldn't have too much of a problem finding enough men to man the pumps. They weren't always rowing and even when they were, much of the time not all the oars were in use.



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Hi Louie;


The pumps were connected to the ship's side by removable timber tubes, square in section,  which were known as 'dales'.  These were taken to a scupper, which,  if my memory is not playing me false,  was sometimes larger than the other scuppers.  The dales were presumably stored near the pump.


The pumps were sited near the main mast,  as this was in what was called the 'well',  and area kept clear right through the hold,  down to the bottom of the ship,  so that the amount of water coming in could be easily assessed.  This was also the lowest point in the ship, and the timbers were sometimes cut away to allow the lowest part of the pump to scoop up water from below the tops of the floor timbers. Some systems of framing left a gap between the opposite end of the first futtocks (navel timbers as they were called at that time) which allowed the end of the pump to be sited at the end of the navel timbers, against the keelson.


All the best,


Mark P

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  • 8 months later...

So as far as I can see, the wheels of the chain pump are at right angles to the keel? I can see that having them that way makes it easier for the water to reach the lands and then run to the scuppers. But are there any cases of chain pump wheels parallel to the keel? Or is it a matter of choice from ship to ship?


I'm getting the the point where I'm about to make my chain pump housings. I'd like to have my wheels parallel to the keel, but I don't want to get it wrong.



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They could be done that way, I think.  The main reason for having them at right angles to the keel is you can make the pump (for lack of a better word) handles long enough to have several crewmen pump.  If they're parallel, then the number of "pumpers" would be limited by the distance from the pump to the bulwark.  And if it happens there's a gun in the way, it would be even more constrictive.

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Yes, I thought that might be a problem - access past the handles if they're running from side to side of the ship. The guns won't be a problem, though. They haven't been invented yet 😁.


But if anyone else has further advice on this issue I'd be very grateful. I'm pretty much in the dark on this but I don't want to make a stupid mistake with it that I later regret.



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