How many men would it take to raise a portcullis?

In practical terms, if you've got 20 or 30 guys trying to get into an undefended castle, it might be simpler for them to just make a ladder and go over the wall, since nobody's trying to stop them. But the portcullis route is fine, especially if they only need to open it enough for one small guy to slither under it and use the winch or whatever. (Although you said the mechanisms are damaged; do they have to be damaged?)

 

If I had to guess, I would say that a portcullis weighs a lot more than 2,000 pounds. Think about it... its a gigantic grate of wrought iron, probably 15 feet wide and at least that tall (I guess that would vary, depending on the castle), with the bars being 6 inches thick and solid.

I would guess your "average" portcullis would weigh 8-10,000 pounds, if not more. So the average man, basically dead-lifting 150 pounds (which for warriors isn't very much), I would say you would need 60 men at least. If your men can lift 250 pounds each, which I still think is reasonable, you might be able to do it with 35 men.

But with that many men, you start running into space problems, as they are going to need to stand side-by-side to lift. You can probably only fit 10 men in a 15-foot wide space... 20 if you get 10 on the other side of the grate.

 

Good question, as I have a portcullis in my story. How many people would it take to power the winch from the inside is what I would like to know if anyone would care to let me know

 

They could use a timber or log as a lever to pry that thing up. It would require less man power and gives more of a working area. If there is something they could move under once it was up, they would not have to hold it long.

 

I found a source that said the liberty bell weighs 2000 pounds.
So a 10-20ft tall gate would weigh more then a bell.

If it is locked, it will take alot more work. But someone climbing over and unlocking would change that.
If the winch still works, they lift it enough to get someone in, or have someone climb over and simply open it.

 

Silly question perhaps, but isn't there a sally-port? Would be a fine thing, all those men working themselves to death to raise the portcullis only to discover the side-door was open all the time...

 

JonSnow was on the right track, but I think he's a bit underweight on the estimate.

One inch (diameter) rebar weighs 2.67 lbs. per linear foot. Rebar is made of steel which has about the same density as wrought iron (490 lbs per cubic ft vs. 485 or so). A six inch diameter piece of rebar would weigh 96 lbs per linear foot.

A 12.5 ft by 12.5 ft portcullis made of uniform material (six inch diameter rebar) would weigh almost 18,000 lbs. That's a construct with nominal 1 ft gaps between any two bars and of uniform construction.

Depending on your period, it's unlikely that a piece of metal that size could be manufactured by standard processes. More common designs were metal rods slatted together or some grouping of reasonably sized (4 ft x 4 ft) tiled lattices slatted together in a similar fashion. Those types would cut your weight down considerably, but you're still talking about a structure that weighs upwards of 12,000 lbs. The mechanism used to open a portcullis was commonly a set of very large counterweights (sandbags or very small rocks ) linked to a system of pulleys (and later gears) to provide mechanical advantage to "several" men or a pack animal working a winch.

That's all pure conjecture, but the math works out and the rest lines up with portcullis's I've seen.

 

Oh yeah, the how many dudes to lift it part...

Assuming a 12 ft high portcullis, if each fellow could stand in a 2 ft space (which probably isn't possible for dudes big enough to do it) they'd need to deadlift somewhere between 2300 and 2800 lbs per man. The world record is something like a thousand pounds, so you're better off tossing a couple dwarfs over the other side to get busy on the winch and pulleys.

 

If that cat can deadlift 12-18k lbs, you may as well just say, "Gotrek, smash!" and follow him in.

 

Somehow, I just know that this ties back to the number 42, somehow.

I just know it does!

 

I knew it!

Stumbled across this today when I was mucking about. Link

 

All the portcullis mechanisms I've seen here in England were always open but I do know they had dead man locks so with the chains smashed someone would have to scale the battlements to get to the winding room in the gatehouse and smash free the deadlocks. Then those on the ground could lever it up enough to prop it open with a baulk of timber, you'd never try to straight lift it unless you were in an urgent hurry and had more men then sense; those things are massive and built of English oak which weighs enough on its own let alone with the wrought iron reinforcing.