10th-11th century Byzantine dromon by Louie da fly - FINISHED - 1:50

[Louie da fly]

I can't remember off the top of my head, Dick. I'll have to get back to you on that.

 

Steven

[BANYAN]

Hi Steven, what Dick maybe alluding to is the angle at which you have drilled the holes into the 'blob'?  Sorry if I have read too much into your comment Dick.  If the mast is angled then the rope should enter and depart the sheave holes on the axis of 'pull' (directly down?) such that the rope does not chafe on the edges of the holes for the sheave?  being square on at the moment you may find the lower one might not be a clean entry?

 

looking good!

 

cheers

 

Pat

[Louie da fly]

Good point, Pat. The foremast should be ok - Prof Pryor has it about 70 degrees from horizontal (i.e. 20 degrees forward rake), but it's at 77 degrees (13 degrees) on my AutoCad drawing . The aftermast, however, is vertical, and there may be a problem with that. I can only suck it and see.

 

Steven

Edited July 24, 2018 by Louie da fly

[Louie da fly]

I'm still very much feeling my way with all this stuff. Would those of you "in the know" think I should go back to a single sheave at the top of the mast, and get the mechanical advantage from multi-sheave blocks and tackle on the halyard downhaul itself?

 

Steven

[Mark Pearse]

HI Steven

 

I have one comment & one question:

 

The spar wouldn't be particularly heavy but the sail would be very heavy, but considering the ready labour on board I reckon they'd be ok about a 1:1 halyard with half a dozen hefty Mediterranean types. There's also the mechanical advantage you get by 'sweating' the halyard, where you lock the tail of the halyard (usually around a cleat) & then above the locked point you pull the halyard horizontally away from the mast (it has a leverage action) - which pulls the halyard up a little bit - & then you quickly take up that slack on the downhaul part, & it inches upwards. Sorry if that's not clear.

 

How would a double sheave in the mast actually work to get greater than 1:1?

 

Mark

[Louie da fly]

Thanks, Mark. I'm not an experienced sailor - I was in the sea scouts when I was a kid. We sailed clinker-built 18 foot ex-navy gaff-rigged cutters. Lots of fun, but I've certainly never studied up on the theory, and my knowledge of mechanical advantage dates back to high school, and never applied to sailing. So maybe I just go with the single sheave at the top of the mast. I still haven't glued the "blobs" in place, so I'm not yet committed (though maybe I should be . . .)

 

I'd thought the double sheave in the mast would be combined with a double-sheaved block between that and the yard, but I admit my ignorance on all this and it might be a really dumb idea.

 

I was originally going to just go with the single sheave (as can be seen in the first foremast I made), then I saw something about double-sheaved assemblies at the top of the mast on mediaeval Mediterranean ships. But that might be completely inappropriate to something like a dromon. Particularly as you say, with oodles of available manpower who needs mechanical advantage anyway?

 

Steven 

[woodrat]

I have been through the Michael of Rhodes manuscript and it is of marginal help. It does show (for an early 15th C galley) that the halyard downhaul uses large double blocks. Also it recommends that the galley have  halyards 8 times the length of the yard which supports the use of double blocks in the downhaul. As for whether the halyard (amantus) goes through a single or double sheave in the calcet (the block of wood attached to the masthead), Michael is silent. However Professor Pryor, in his 1984 study of mediaeval lateen rig, does illustrate laterally orientated double sheaves in the calcet. Whether this was the case for byzantine warships? Only the Black Sea will tell us.

Dick

Edited July 25, 2018 by woodrat

[BANYAN]

I have no idea how it may actually been set up Steven, simply looking at the mechanical aspects. 

 

The double sheave calcet has merit as Woodrat has described.  Even with a hefty crew there would have been minimal manning of the upper deck as the oarsman would still be required until the sail has been hoisted, and immediately available when the sail is lowered.  Then again they may have employed the archers etc to assist in this task, so assess this option with a 'grain of salt'

 

I think a single block at deck level would have been sufficient with the standing end of the tackle attached to a becket on the top of the single block, led up to one sheave in the calcet, back down and through the single block then back up through the other sheave in the calcet, with the crew then working the running end of the tackle.  This set-up would have allowed a much more 'controlled' and faster method of raising and lowering.

cheers

 

Pat

[Louie da fly]

Dick, just checking - Prof Pryor shows the sheaves in the calcet across the ship, not fore and aft? The St Nicholas picture could be interpreted that way, and the Greek Fire could well represent two transverse sheaves. It would mean the halyard would be belayed to the side of the ship, not fore and aft? I think I might do that - it should cancel the problem of chafing.

 

Pat, my reading suggests that not all the oarsmen rowed all the time - sometimes only the forward ones rowed. The Jason Voyage guys certainly did this, rowing in shifts to give each other a break. Again, all the upper oarsmen doubled as soldiers in battle (so the archers were drawn from their ranks), and so there should be plenty of manpower available. And the ship could be kept under way by the lower oarsmen if needed while the sail was raised or lowered.

 

I like your idea of the double sheaved calcet and a single sheaved block. It does seem like a sensible way to go - no need to make raising and lowering the sail any more difficult than it has to be. And certainly, there have been a decent number of blocks discovered in the archaeological finds.

 

Steven   

Edited July 27, 2018 by Louie da fly

[BANYAN]

Sounds like you have come to grips with the masts now Steven; look forward to seeing the results.

 

cheers

 

Pat

[woodrat]

I'm sure prof. Pryor wont mind me posting this illustration from his 1984 paper on mediaeval lateen rig. As I read it there is a double sheave through the "calcet" which is laterally directed. I think it would be correct to have either single or double halyard downhaul blocks.

Dick

[Louie da fly]

Thanks, Dick. That seems to work.

 

Steven

[woodrat]

Just a thought. With a laterally orientated block in the the "calcet", when tacking or wearing, the yard would be placed on the other side of the mast which would surely jam the halyard?See Landstrom "The Ship" for the method of tacking a mediaeval lateener. 

Dick

[Louie da fly]

Dick, this objection would presumably also apply to Prof Pryor's 1984 lateener, but on reflection, if the halyard is belayed to the gunwale I think the yard should slip in between the mast and the halyard so it shouldn't be a problem.

 

On the other hand after a lot of soul searching (and an equal amount of waffle) I've decided to go back to my first thought and have a single fore and aft sheave in the calcet (a name which I discover comes from the word khalkision used in the Byzantine texts on dromons to describe a mast with sheave incorporated in the top).

 

And a pair of single or double-sheaved blocks for the halyard downhaul, leading aft from the mast. Am I right in thinking single-sheaved blocks would not convey any mechanical advantage?

 

Steven 

 

 

Edited July 31, 2018 by Louie da fly

[Louie da fly]

Here are the new calcets (might as well use the name - better than "blob") with a single sheave each. One has already been glued to its mast, the other ready to do so. One advantage of carving them separate from the mast itself is the sheaves can be aligned exactly fore-and aft without having to worry about lining them up with the tenon for the mast-step.

 

 

And here are the three two-sheave calcets I made while I was waffling making up my mind. One still under construction, to replace one I wasn't happy with, when I changed my mind.

 

 

And look! Here's another milestone - both masts in place, dry fitted. Starting to look like a ship! From above at various angles . . . shows how the mast angles can fool the eye. The midmast is vertical; the foremast has a rake of 13 degrees.

 

 

 

And here she is from the side - with a lovely Ballarat winter's day outside.

 

 

Steven 

[MESSIS]

great to follow Steven!

[GrandpaPhil]

Very nicely done!

[Louie da fly]

Thanks everybody for all the "likes".

 

Having pretty much sorted out the masts, I'll be putting them to one side till they're needed. There's one more thing still to do, which is install the mast partners, the cross beams that support the masts just below deck level. I'll be posting on that shortly.

 

The next thing to work on is the peronion or "spur", used in ramming enemy ships. Normally one would expect such a thing to be built strongly into the ship's structure as the forces involved in a ramming are pretty extreme, but Age of the Dromon shows that the Byzantine spur was definitely a separate piece, which was then fixed to the ship with a coupling (katakorax). 

 

How exactly this is to be done is currently a bit of a problem, as these things would have been pretty heavy and it would be necessary to transmit the forces in a straight line of thrust, rather than at an angle, so as to avoid damage to the ship. Also, sailing in any kind of a sea with one of these things bouncing around, coupled to, but not built into the ship would have imposed all kinds of nasty forces on the bow structure. I have some idea of how to do this, but it's all speculation - we have no idea how it was really achieved, and unless a dromon with peronion attached is found among the Black Sea wrecks, the chances are we'll never know for sure. 

 

One thing is that a couple of contemporary pictures, several centuries apart, show a support - perhaps a chain - running diagonally down from the prow supporting the spur near the business end. This would stop the spur from falling too far downward but wouldn't stop it being flung upwards or sideways by the motion of the vessel. Perhaps there were also side chains (or ropes) running back to the cheeks of the bow?  If taut enough this could keep the spur pretty much static, much as a martingale boom does for the bowsprit in later ships.

 

The diagram in Age of the Dromon shows the spur as 7 metres (21 feet) long. I made a balsa mock-up and if it's to be strong enough to withstand the shock of collision it seemed much too hefty for a ship this size - and the spur was almost certainly made of oak or some other heavy timber, and possibly metal-sheathed as well (see below).

 

I cut it back to 6 metres

 

5 metres

(oops! lost the photo!)

 

and 4 metres

The last two seem to be about the size one would expect, and something like the size shown in contemporary pictures (though these need to be taken with a pinch of salt). This would work better and impose less strenuous forces on the ship's bow.

 

But I'd left out of my calculations the pseudopation (fortified wooden forecastle), which (in my version at least) leans forward at the bow.

 

 

I think this takes the 4 metre spur out of the running - it wouldn't be far enough forward of the front of the forecastle to engage an enemy ship without a risk of damaging one's own vessel. So maybe 5 or 6 metres, but no more.

 

The other issue is that the spur would be immediately forward and below the siphon - the Greek Fire projector. As it seems to have been pretty much the same as a flame thrower, the chances of flaming liquid landing on the spur would have to be taken into account, so I believe it would have been sheathed in metal, probably iron. It would not have to be very thick sheathing, just enough to keep the spur from catching fire from spills of Greek Fire.

 

So I've got some fun ahead working out exactly how to attach this thing, how long it will be etc etc.

 

Steven  

[Louie da fly]

Just checked again in Age of the Dromon and discovered there's documentation for the 13th century Sicilian galleys having spurs that were 10 metres long and 250mm thick. Presumably Prof Pryor applied his usual 3/4 proportioning between the Sicilian galleys and dromons to come up with the spur length for the dromon.

 

Looks like I'll have to go back to 7 metres - and maybe 200mm thick. But that would be at the base - maybe if I make the spur quite a bit narrower as it approaches the point it will reduce the "tail wagging the dog" effect.

 

Steven

[BANYAN]

Looks good Steven.  WRT the spur coat I think recall reading somewhere that these were bronze; may be worthwhile investigating.  If I find the source of the info I will let you know.

 

cheers

 

Pat

[cog]

for what it's worth, the Greeks and Romans used bronze spurs, also nailed to the hull, bow, and keel

[Louie da fly]

Pat, I'd appreciate it if you can find it.

 

Carl, I agree. But the Ancient Greeks and Romans used rams, attached directly to the hull which was shaped to receive them. The spur was a separate piece - rather like a knight's lance. The reason I thought of iron is simply that it's less dense, so using iron rather than bronze would probably reduce the weight and thus the leverage of the spur.

 

Steven 

[Baker]

Interesting build to follow.

I had no idea how such a ship was built at that time. Until now.

Great work Steven

[ESF]

Steven,

Your work at such a tiny scale with such delicate lumber is very impressive.  Congrats on a wonderful build.

 

Steve

[BANYAN]

I will have a look later today Steven; hopefully, find it but now that Carl mentioned the rams I am beginning to wonder whether this was the association n my befuddled brain   get back to you soonest.

 

cheers

 

Pat

[Mark Pearse]

Hi Steven

 

getting ever more interesting... Do you know if the spurs were designed to break away at all?

[Louie da fly]

Thanks Steve, Patrick and Pat.

 

Another reason for the idea of iron plating on the spur is that Prof Pryor mentions a reference in the early 13th century Itinerarium peregrinorum et gesta Ricardi Regis (Itinerary of the pilgrimage and deeds of King Richard) to a (probably Italian) galley with a "rostris ferratis" ["ironed" spur]. (Age of the Dromon, p. 203)

 

However, in this case the iron plating could not have been to protect the spur from the effects of Greek Fire, as this weapon was a closely guarded Byzantine secret. Perhaps it simply means that the spur had an iron point.

 

In the Byzantine case, any metal would have been sufficient to protect the spur, at least temporarily. It would probably come down to which was easiest to get and/or apply. Lead would also be possible, but might be inappropriate because of its weight. Bronze or copper were probably easiest to get hold of and to work, so bronze might well have been used. This is all speculation anyway; we don't know it was done, merely that it would seem to be needed.

 

Steven

[Louie da fly]

Mark, there are certainly no references to this in the contemporary records, and as far as I can see this was not part of the tactics used. The spur seems to have been used to smash your opponent's oars and preferably steering oar and allow your marines to attack from the relatively unprotected stern, and perhaps even capsize the opposing ship. As usual, most of this is speculation, as contemporary evidence is either lacking or untrustworthy.

 

Steven

[BANYAN]

Hi Steven, at this point I would suggest that my 'recollection' may have been from a post in a build log in an earlier iteration of MSW which was about a bireme or trireme - and most likely referred to the 'ram'.

 

I think you are correct in your assumption/choice of the iron spur - I found the following in "The Age of the Galley" edited by Robert Gardiner  (Conway Books) page 103 in the Chapter "From Dromon to Galea..." - I have omitted the greek terminology:

 

"..The prow housed the ship's main offensive weapon, a flamethrower for Greek Fire, above which was a fortified foredeck.  The prow also had a spur, referred to by the Anonymous by the classical Greek embulos, which was either made of iron or iron-clad. .."  

 

The source reference used for this is "Anonymous, #6.2: Eti de kai ..." This refers to an anonymous treatise commissioned by the Pariclios and Parakoimomennos 'Basil', dated c AD960.  Apparently the anonymous author derived much of his information on ships from the Onomasticon of Julius Pollux  c AD178. 

 

The information in the "The Age of the Galley" is an article in the Mariner's Mirror 79_4 (1993), pp387-92 which argued that dromons had spurs and not rams.

 

I hope this helps ?  Do you have that article from the MM?  If you don't I do have it, and can get the relevant info for you (send me a PM)

 

cheers

 

Pat

Edited August 2, 2018 by BANYAN

[Louie da fly]

Pat, 

 

The local library has "Age of the Galley" and I photocopied the section "From Dromon to Galea" about three years ago - in fact it was what inspired me to begin this build!

 

Looking back at this quote I see that the original Greek passage says "Moreover, hides should be fastened to them [the dromons] against the ram [spur] of the enemy, so that the iron glances off in reaction and does not take hold . . ." 

 

I'd argue against the whole spur being made out of iron. First, making something seven metres long entirely out of iron could be done, but would be very difficult with the technology of the time, and anyway it isn't necessary - an oak spur, sheathed with iron would be considerably stronger. Wrought iron, made by hand, would be full of faults and inclusions of slag -  the difficulty of making a sword at the time testifies to this. And wrought iron is pretty "bendy" - and far heavier than timber. I wouldn't use it as a spur.

 

It's my belief that the "iron" in the above quote is an iron-sheathed point. A spur would have no need for any more iron than this if you weren't trying to protect the spur from the flames of the siphon. And as only the Byzantines had Greek Fire, enemy ships didn't need to protect their spurs against it. But as the Byzantines did have it, one would expect them to have metal sheathing and perhaps it was iron. It wouldn't have to be strong, just cover the wood of the spur.

 

No, I don't have the MM article but I'd be very grateful for it. I'll PM you. Many thanks.

 

Steven