Marathon 490 BC

[Jim Webster]

I have boosted the Persians to 120,000 or so. I've given them 100,000 oarsmen etc.

Remember, a force of 15,000 men who may well be experienced soldiers, are going to sneer at 11,000 city militia who've just been called up and are going to think they greatly outnumber them.

To get a force of 60,000 Persian troops you really need to show that the Persians were in the habit of doing what Greeks could and did do, ask their infantry to double up as Oarsmen.

Jim

[Patrick Waterson]

To get a force of 60,000 Persian troops you really need to show that the Persians were in the habit of doing what Greeks could and did do, ask their infantry to double up as Oarsmen.

Jim

In a word, why?

Patrick

[Jim Webster]

Sorry Patrick,
I posted it when being distracted by other things.

As far as I can see, we have 600 triremes and an unknown number of transports.
Now we know that we have horses to transport, and a trireme in Persian service probably carried 40 marines
Herodotus, VII.184.2

So your Marines alone, on 600 ships have potentially 24000 marines.  (or replace the marines with 'ordinary infantry' to taste.)
The transports can carry horses.
So If we take the Belisarius figures, with a similar number of ships we can carry 15,000 men.
If we take Herodotus's figures for marines, we can have 24,000 infantry and a number of cavalry.
Both can be said to outnumber, even considerably outnumber 11,000 city militia infantry
I see no reason to go to 60,000 men

Jim

[Patrick Waterson]

Thanks, Jim.

You are quite right about a trireme in Persian service carrying 40 marines, but this would be for sea fighting rather than transporting an army, would it not?  I have in mind various illustrations of triremes in naval battles where we have a huddled collection of 30-40 chaps at one end of the ship and a vast emptiness for about 7/8 of the deck.  Assuming you want to move an army rather than just disembark marines for land fighting, would it not make sense to cover a greater area of the deck with sprawled troops and sail a bit slower?  It is not as if the Persians were expecting any serious naval opposition in 490 BC, so being in fighting trim for a naval battle was probably the least of their worries.

The infantry could be carried in addition to the marines, or the marines could be left off for greater carrying capacity (which seems logical if one is not expecting a sea fight).  A certain amount of deck space would need to be left free around the mast for raising and lowering the sail, and crowding the steersmen is never a good idea, but about 4/5 of the deck could be used to transport men, so with about 2,000 square feet of deck that gives about 1600 square feet of usable sitting space (or more probably lying down or leaning over the edge feeling unwell space) and if we give each man 6'x1.5' (9 square feet) then by a coincidence that struck me as I was working it out just now we get 178 men per trireme, which is exactly what the Athenian Syracusan expedition worked out as having.  Neat or what?

Patrick

[Jim Webster]

Athenian ship sheds were 40 meters long and 6 meters wide
Assume a square ended ship just big enough to fit into the ship shed and that the entire thing was decked.
Assume an infantryman takes up 1 metre by 1 metre. Approximate 'at ease' spacing
Your 40 infantrymen would take up approximately 20% of the deck space. Give them room to lie down and that's 40% of the deck
Go back to having pointed ends and having to leave space for seamen to move about, allowing for the fact that we're not talking an aircraft carrier and it might to be totally decked 40 marines are going to take up a fair proportion of the deck
Look at http://www.youtube.com/watch?v=7da52cJLwW8, there is a big gap right up the middle of the deck.
When you look at that ship, explaining exactly how you get 100 infantry on there without them rowing is problematic.

I don't think they're huddled at one end.

I don't think you've grasped the logistics of it all.
For a start, you put 100 infantry on top of the deck, even if they fit, you have screwed, utterly, the balance of the boat, she's suddenly deperately top heavy

Swapping marines for infantry is irrelevent, except that infantry might expect to carry more kit and get in the way more. It doesn't increase the number of men you can carry.
Indeed putting Persian infantry on instead of Marines would have the advantage of guaranteeing the loyalty of the ship.

Jim

[Mark G]

I have to say, 24 000 does feel about right for this sort of expedition., which I can happily 'medise' to 25 000 to fit with the perferred numbering system if you want.

it also gives a hefty numerical advantage on its own, leaving out the separate boat crew who would have been identifyable *.

to put the command and control into perespective, 24-25000 is less than the Republican Roman consular pair of 4 legions.

It is important to stess that this expedition was not a massed call up with the King present and for which any old pair of arms brings more prestige - this is a specific military task force with a specific role.

I don't think Patricks numbers hang on 'outnumbered', rather I think they hang on the 7000 Athenians on 40 triremes -but I can only accept that number if it includes all the fighting men who disembarked having to crew the vessel to get there.

175 fully equipped hoplites hanging about on deck in all weather for a sea voyage of that distance looks like a disaster waiting to happen, and coincidentally, 170 seems to be the normal number of oarsmen for a trireme too.

Conversly, the Persians would have used sea faring subects to provide the vessels and crew, and it seems so much more logical and believable that they needed many extra boats to carry the same number of fighting men as an Athenian army which could do both tasks.

But we are back to the 'Million Men of Xerxes' argument again here, and I think the same sides are shaping up again with pretty much the same lines of argument too, so in the absence of anything else to change an opinion, I'll bow out at this point.

* - I am remined of a sceene in A Very British Coup, when the army displays Soviet vs Nato military strengths to argue for a retention of US nuclear weapons, and it is pointed out that the Soviet figures include cooks, drivers, HQ officers, medics, reservists etc, whilst the Nato numbers only count fighting men (and didn't include the French, who would hardly be bystanders in the event of a Soviet invasion). 

[Patrick Waterson]

Mark is being very gentlemanly here, so despite some reservations I shall leave his statements as they are and just add that the sides shaping up are essentially classical sources vs modern opinions.

I would however beg leave to question Jim's statement that putting 100+ men on the deck of a trireme is going to upset its balance: it will cause the vessel to ride lower in the water, but unless you add something like towers or a corvus this will not affect its inherent stability unless - and this is important - the men all crowd to one side and a big gust of wind hits the sail at the same time, which is anyway more likely to snap the mast or rend the sail of a trireme than to roll the ship over.  The ram - large, heavy, below the waterline - is a great stabiliser and damper of load-induced movements (had the Mary Rose been built with a ram, it might still be with us today).  Mediterranean mariners, particularly in galleys, anyway avoided bad weather rather than sail through it (when they guessed wrong they lost horse transports - as in the Carthaginian invasion of Sicily - or whole fleets, in the case of the Romans), the point being that they would not be at sea in anything but good weather, at least in the Aegean, with its numerous island refuges, if they could possibly help it.  In any event, as I mentioned previously, the Athenians were able to take 7,150 men on 40 triremes from Athens to Sicily (with a few stops along the way), i.e. 178 extra men per ship, without this being a problem, so I do not see any question of potentially upset balance (or having a big gap in the middle of the deck) as being an argument against this troop capacity.  Thucydides says it was done, and I think he was a sufficiently reliable source on which to base estimates.  What we can do is guess how it was done, not (unless we have good evidence to the contrary) challenge that it was done.

The exact details of fitting 178 extra men onto the deck of a trireme must obviously remain conjectural.  For what it is worth, I would suggest that the deck gap could be covered by removeable gratings (they have to be removeable to let the oarsmen in and out) if increased space is required, and that one does not need seamen moving about the deck - just a couple at the steering oars with the ship's officers, a few more to raise and lower the sail (which is basically up or down and not being continually adjusted) and maybe a few more - or the same men - to distribute water around at intervals.

Now I do take the point that the Persian expedition of 490 BC was not arranged by Athenians, but by the Persian Empire, but would ask where and how the Athenians orginally learned how to pack 178 men onto a trireme - did they work it out for themselves, or had someone done it before?  The trireme of 490 BC seems to have been the same basic vessel as the trireme of 415 BC, so I think what works in 415 BC would work in 490 BC.  Is there any reason to believe this would not be the case?

Patrick

[Jim Webster]

Patrick
The obvious way to fit 178 men into a trireme is to put them on the rowing benches

As for the ram adding to stability, a ram, 200kg of bronze stuck on the front end, (the olympias) is not a keel. It will slightly reduce the centre of gravity but as a weight below the centre of gravity doesn't do more than counter 3 naked men above the centre of gravity, never mind 178.

I'd recommend anyone look at the video of the Olmpias I mentioned above. Look at how tightly packed the oarsmen are packed to get 170 of them in, involving three 'decks'
And then to expect to get 178 soldiers on the two parallel narrow flat decks above them is I feel stretching credibility.
If we assume that an infantryman, plus his kit, plus some stores, comes to 100kg, that is a total of 17.5 metric tons.
The weight of the Olympias in total is only given as 70 tons and if you look at http://en.wikipedia.org/wiki/Trireme

Weight distribution was so critical that the holes for the Thalamian oars are just above the waterline. So effectively the crew, probably another 17 tons are all above the centre of gravity (but as close to it as possible) and you'll wanting to sling another 17.5 tons on the top, as far from the centre of gravity as you can

Jim

[Patrick Waterson]

A worthy set of observations, Jim.  However ...

While the ram is not a keel, it remains a considerable stabilising force, and its position at the head of the ship actually multiplies its stabilising influence while the ship is moving (pressure from a greater volume of water per second and all that).  Incidentally, I do not recall the Romans in the First Punic War having stability problems in battle with significant complements of legionaries and a corvus on deck.  (Weathering storms off the south coast of Sicily was quite another matter.)

The centre of gravity will tend to get lower as the extra load puts the ship lower in the water (not sure exactly how the metacentric height would be affected, but basic principles suggest the ship actually becomes more stable as the two diverge).  Now for a hypothesis on my part: I suspect that a trireme being used as a transport might well dispense with the lower deck of oarsmen because their oars could end up mainly in the water: a point against this supposition is that the Athenian ships that went to Syracuse all seem to have been employed in a combat role after unloading their troops, implying they took their entire complement of 170 rowers (the question then being whether the thalamites rowed - or sat idle during the voyage hoping the thranites had gone easy on the beans).

All in all, I suspect we tend to under-estimate what triremes did and could do.  Unfortunately with the Greek financial situation as it is, I doubt that any suggestion that they try to see how many men dressed as hoplites can get on the deck of the Olympias would be favourably received.

That basically leaves us with Thucydides' description of the Athenian expedition to Syracuse as our best rule of thumb for the period.

Patrick

[Jim Webster]

The Romans were using Quinqueremes, heavier ships, with 400 crew or thereabouts and designed to have up to 120 marines. And even they had major problems in storms

Jim

[Patrick Waterson]

Indeed they did.  Naturally, anyone with sense (which excluded several First Punic War Romans) stayed out of the way of storms or got ashore or into the lee of an island before they struck.  Datis, Artaphernes and co. did not encounter any storms, and one would expect they chose their sailing times with this in mind (a later Persian fleet that tried to double Mount Athos did run into one and was not so happy, with or without masses of troops on board).

Essentially, a Mediterranean war galley of any flavour, loaded or not loaded, was pretty much at the mercy of a storm.  The trick was to avoid storms in the first place.

Incidentally, Polybius (I.26) gives the crew of a quinquereme as 300 men (presumably 150 per side, 30 per oar bank).  The Romans did indeed put 120 troops on each deck, as they had in Polybius' words: "made preparation for both eventualities, a seaborne battle and a land invasion," their troop allocation thus being something of a compromise, and presumably a useful upper figure for the number of men one could cram onto the deck of a quinquereme and expect to be able to fight in a naval action rather than the maximum number possible.

Patrick

[Erpingham]

I've been catching up on this interesting tale and was encouraged to go and look at my copy of Morrison & Coates the Athenian Trireme.  A few key points bearing on the above :

• They believed triremes from Asia Minor were decked across, unlike Athenian ones, because they used boarding tactics
  Top heaviness is, contra seen as a major issue.  They quote Herodotus (8-118 1-4) an apocrophal tale of Xerxes having his entourage jump into the sea during a storm because they are making the ship top heavy.  Herodotus thinks this is rubbish because Xerxes could just have ordered them below.  Overloading was a risk, especially in bad weather.
  Their commentary on ships of the earlier period suggest that a troop carrying fleet, as opposed to a battle fleet, could carry 40 armed men above normal crew.  They concur on horse transports carrying 30 animals, stating these would be converted triremes using 60 oarsmen.

[Patrick Waterson]

Interesting points, Antony (nice to have you joining this discussion, by the way).

The one about Herodotus VIII.118.1-4 is intriguing, because my rudimentary knowledge of naval architecture suggests that deck-loading a trireme will raise the metacentric height, making the ship more stable in normal conditions because the rate of roll is decreased but less stable in violent weather because the vessel is 'tender', which means if pushed beyond a certain angle of heel it is difficult to recover.  The basic trireme configuration (deep-ish, narrow-ish, flattish-bottomed) makes for an inherently stable design.

This would suggest that overloading a trireme (if adding the calculated 178 men for 'trooping' was in fact an overload) would be dangerous only in bad weather - which was anyway very unfriendly to triremes.

Herodotus also points out that he believed that particular tale to be apocryphal because "the king, as I have already said, returned to Asia by the same route as the rest of the army" (VIII.119).

Do Messrs Morrison and Coates comment on Thucydides VI.43 (which has 7,150 troops being carried in 40 transport triremes)?

Patrick

[Erpingham]

Do Messrs Morrison and Coates comment on Thucydides VI.43 (which has 7,150 troops being carried in 40 transport triremes)?

Alas no, though they do quote enough of Thucydides to suggest most of the fleet were standard triremes, the presence on board of which of extra troops in action was a problem, affecting manoeuver.  M&C believe the key issue was roll - the additional marines caused the ship to be unstable, interfering with effective use of the oars.

Your quote above now suggests that the 40 triremes were transports.  If they were the 60 oared converted horse transports type, they would have had more capacity.  The rule of thumb is a horse takes as much room as 5 men, I believe, so a 30 horse carrier would have room for 150 men, which isn't too much of a stretch to get to the figure needed.

[Patrick Waterson]

Thucydides says that the Athenians had 134 'trieresi' (triremes) and two Rhodian 'pentekontorin' (pentekonters) on the expedition.  He notes that touton Attikai men esan hekaton, the Athenian triremes numbered one hundred, hon hai men hexekonta takheiai, of these sixty were swift, i.e. in fighting order, hai d'allai stratiotides, the others were carrying troops.  One notes the inference that the troop carriers were slower.

He does not draw any differences in construction between the troop-carrying triremes and the triremes in fighting order, and lumps them all together in one category (100 Athenian triremes), so it looks as if he understood them to be identical vessels fulfilling different roles rather than differently-built vessels.

The single horse transport (hippagogos - one has to love the dative, 'hippa-go-go') is listed separately.

Whether the forty triremes used as troop transports had a reduced rower complement is an unanswered question.  I would suggest from the fact that every Athenian trireme at Syracuse seems to have been committed to battle when things got tough that the rower complements may not have been reduced, but this assumes that nobody was co-opted as temporary rowers.  As you point out, if we assume 60 oarsmen per transport trireme (essentially one level of oarsmen) then much more space becomes available, and 150 men (a 30-horse equivalent) is not far from 178 (and men in close proximity do not bite each other - usually - so can perhaps pack a little closer).  The key question that arose early in this thread is whether a Persian fleet of 600 triremes could have transported 60,000+ men, and one way or another the arithmetic is suggesting that they could.

Patrick