I blame the portraitists - you’re right, I just read up on the construction paragraph, not the figure captions.
As I said in the thread on ‘earliest bicycles’, pedal machines have a lot of stress on the bearings and shafts for the pedals and cranks (top atheletes can output half a horsepower for short. Too much stress for wood, and, while I’m no metallurgist, I think too much stress for anything short of wrought iron. Which was never cheap in antiquity. Plus, just like slaphead said, making precision metalwork without modern machine tools takes a lot of skilled work.
So could some mad Greek tyrant have built a pedal-powered ship? Perhaps.
Would anyone sane – even if they didn’t have to pay for the research into propeller shapes and pedal design --have spent that much money and valuable iron on building a large pedal-powered warship which was going to end up a literally sunk cost at some point? No.
Though I will point out that traditional galleys didn’t have sliding seats like modern rowing shells, so the maximum power output per person was a lot lower.
As a past rower, I’d like to correct this. The time for the recovery (oars out of the water) should exceed the time for the drive (oars in the water). If a crew is whipping the oars through the air fast enough to have the recovery faster than the drive, then the check at the catch will really upset the boat, as tremorviolet pointed out. Even at stroke rates above 40 strokes per minute, you still strive for long relaxed recovery and then explosive drive. Cheers.
My money would be on the oars. You’re using the power of your arms, legs, chest, and back for rowing, and only the power of your legs for pedaling.
Also, wouldn’t the pedals involve some sort of resistance from the friction of the gears, which would cause some of the pedaling energy to be wasted?
It’s not exactly bicycle-like but from the Song dynasty on the Chinese used treadmill-operated paddle-wheel ships extensively on rivers.
Pictures (3rd and 4th)
Short description of a specific battle
Unfortunately the best overview that I found so far is in German.
And if you mount the treadmill on the boat’s long axis, you need no gearing whatever to drive the propellor shaft. More variation in speed than with a pedal crank, 'cos at higher speeds you just have the slaves climbing two steps at a time.
For modern boats, the fastest human powered boat is a air propeller hydrofoil
http://lancet.mit.edu/decavitator/
Brian
There was a bicycle shop in Marin county right next to the local rowing club’s boathouse where I used to row. Someone from the bike shop fitted a racing scull with a crank and driveshaft to a rear-mounted push propeller (in the water, not the air). He experimented with a variety of propellers to get the most speed, but ended up refitting with one which provided more practical sustained travel.
Even with the high speed prop, there was no way he could keep up with a double-oared single scull.
The advantages of putting the propeller in the air and using hydrofoil blades in the water turn this situation around, but for in-the-water props and comparable human power, there is no question that by using the back, legs, and arms together the rower can deliver enough extra power to overcome the mechanical disadvantages of oars.
I’m of the opinion that the question can’t be answered. The hangup is the efficiency of the chain mechanism that drives the propellor.
You don’t row with your arms. You row with your back and leg muscles mainly.
Anyway, neglecting the efficiency of the chain drive and assuming everthing else equal the propellor should win. Screws replaced paddle wheels because of greater efficiency.
However, you can’t neglect the chain drive efficiency.
I keep thinking that the rowing motion provides quite a bit of power, except only in the one direction. If you have the gearing technology to connect that many legs to one or two screw propellers, then you should be able to come up with some sort of dual-opposing row mechanism connected to a propeller shaft as well. Something like an aquatic handcar.
Let’s borrow 170 rowing ergometers and 170 stationary recumbant exercise cycles, couple the driveshafts together down the centerlines of two triremes in the manner of opposing pistons with appropriate gearing to a propeller shaft, thus:
H H H H H H H H H
----------------------- 8
H H H H H H H H H
In this configuration the rowers wouldn’t need to be sychronized any more than the pedalers and the reciprocating actions would thereby be averaged.
The rowers will produce more horsepower and better boat speed, but they’ll burn energy faster and can’t sustain their top speed as long as the pedalers.
FWIW, a modern pedal gear mechanism has been developed which permits multiple unsynchronized inputs to contribute force to a single drive chain. See conferencebike.com. Nothing on the site explains the mechanism, but I’ve seen it in operation. Definitely works.
I’ve seen a hydrofoil kayak http://www.foilkayak.com/ - has anybody tried a hydrofoil rowing skull?
intersting reading
http://rowersworld.com/Community/viewtopic.php?t=2634&postdays=0&postorder=asc&start=0&sid=957e6b7c0a8ca014038b251da14609bf
http://www.foils.org/human.htm
Brian
I don’t think anyone has mentioned it yet, but what if something breaks. Something like a prop shaft breaking would take out the entire system and they would be stranded. However, with oars, I can’t think of one thing that could break with such catastophic implications.
In a racing shell if the seat guides on the #8 (stern) oarsman jam, the whole boat is hosed.
Hopefully some of the original posters are around. As it seems this thread is kina old. & I kinda wish i’d known of it bak in th day. But it seems there may actually be a chance to have race between 2 relatively equal craft of this type. Plz checkout: www.trireme.org . Fully-functional authentic trireme comin 2 new york from greece. We had a recent thread on our facebook page debatin this exact thing. In fact I had independently mentioned pedal pwr even b4 I knew of this here thread. & one of the trireme models in a museum mentions pedal power in a caption under display. & I’ve thot of almost evryway this could be done too for yrs.
What was the actual tactical use of the oarsmen? If I’m not mistaken, they used the sails as much as possible while cruising. Were galleys generally rowed in battle, or were they sailed with oars used for bursts of speed and maneuver? In pictures I’ve seen of galley battles, they universally had the sails deployed.
It was all about oars in battle. Sails were a hindance in tight quarters and the men who would have been setting and adjusting them were better used in fighting. Once incindiery weapons became common, sails were an even bigger liability.
Mythbusters needs to tackle this. It would be an interesting event, and have a slim chance of damaging someone’s house. 
Not mentioned so far is maneuverability. This is extremely important in sea battles.
And paddle-wheelers (propellers were not used in ancient times, and efficient designs didn’t come until the 1800’s) are poor at maneuvers. Stopping & reversing are particularly hard. In the close-in battles of ancient times, I think that alone would be enough to tilt the scales. (To say nothing about the technical feasibility of chain drives, gearing, etc.)