and I was wondering if anyone could tell me what i’m seeing (like for example what specifically does the wheel do that the sailors are spinning and heaving back and forth?) and how exactly does a ship lose its anchor?
How do they measure the depth of the anchor? (I noticed the video mentioned fathoms, how do they know this?)
What caused all the smoke/dust to billow into the room? Why does this happen? (Friction related?)
I am no sailor but it’s clear that the wheel is the brake and that they wound it off so far that they couldn’t get it back when they needed it.
They know the length (A fathom is 6 feet) by the white marks on the chain. Bear in mind that it’s not just hung down to the bottom, but laid out along the sea bed for a few fathoms.
The wheel is the brake on the capstan (the red-ish winch that the chain passes round).
The seamen release the brake to allow the anchor and chain to fall to the sea floor. What happens is that the chain is stuck, and does not release. They keep unwinding the brake until the anchor starts falling free. At that point they need to reapply the brake to control the fall. But with the brake released too far, they cannot reapply it fast enough, and the capstan is spinning so fast that they cannot regain control.
The dust starts off being rust and dirt off the chain being thrown up due to speed, and sparks struck off the steel chain as it flaps. Eventually, the brake drums and/or capstan bearings overheat, adding to the smoke.
As the chain runs out, there are white links to indicate the depth - these white sections count out the fathoms of chain. Eventually, there is a section called the danger section, marking that the end of the chain is near. This is the signal to clear the area, as the loose end of the chain is about to flap free from the capstan before dropping out of the ship, tearing apart anything or anybody in the way. The end of the anchor chain is not fixed in any way to the ship, to allow anchor release in a hurry. Also, the falling anchor would rip the ship apart as the chain went taut if it was fixed.
It’s unlikely the anchor itself was still falling - that would mean the water was much deeper than a ship would ever normally choose to drop anchor in. The chain itself is of course plenty heavy enough to keep falling of its own weight.
How would the capstan (brake) slow down or stop the chain. It seems like once it has some momentum going, it was going pretty fast, you could stop the capstan and the chain would just keep slipping past it. I can’t imagine there’s really any friction between the chain and capstan.
Even when you see capstans to raise and lower sails or move rudders it’s rope vs metal (or wood) and the rope is wound around the capstan at least once, sometimes multiple times. I understand that can’t be down with a giant chain, I’m just curious how this system works.
(A few seconds of Googling suggest that there may be a windlass involved. The windlass would actually be the machine that does the braking, letting out and pulling back in of the anchor. The capstan seeing in the video may just be acting is a pivot so the chain can turn the corner. But I could also be very wrong. This is way out of my field of knowledge.)
I’m also curious as to if they lost it by accident or on purpose, however, the only reason I ask that is because someone just so happened to be recording it (and backed up near the end).
Lastly, as mentioned up thread, the end of the chain will whip around as it exits, why no safety guards? It seems to me that all it would take is a simple guard, a half pipe shaped glide that ‘directs’ the chain from where it was coming up, around the capstan and to the hole where it went back down. In general, the chain would never even touch this, so it wouldn’t wear out or need any maintenance, but when the anchor is lost (on purpose or by accident), it would keep the end of it from tearing the room apart (including any people nearby).
I watched the video – fascinating! – and I think I can see the irregular surface of the upper knob (?) of the captstan – the big red thing. It looks like it’s made with extrusions that mate with the gaps in the chain. Something like very short, blunt gear-teeth, sort of, which grip the chain.
Amused at the one guy who puts his hand over the camera.
The capstan is not a round drum but has notches that match the anchor chain so it can not slip around the capstan. I doubt that they were slipping the anchor on purpose. That is done only in emergencies.
Any safety guards would be in the way of normal operation. The damage done would not have been structural.
But I would not want to be either the Captain or the chief engineer on that ship.
I don’t see the notches (so I’ll take your word for it). Are they notches or are they more like sprocket teeth that would/can actually grab the teeth? Whatever they are, you have to assume they protrude enough to raise the chain back up as well.
The Wildcat, which they mention in the video, makes sense. As long as there’s tension on the (properly engaged) chain, I can that it won’t/shouldn’t slip past it like it would on the type of (smooth) capstan I was thinking of.
As we saw, the end doesn’t flail about that madly. But it does apply a lot(!) of force within the small area it whips around in.
So to do any good, the guard would need to be A) very close to the chain path, and B) very stout. More than anything, the guard would occupy the danger space so folks wouldn’t stand there. It’s simpler just to paint a red area on the deck or simply know not to stand there.
I’m frankly a little surprised the brake station was back in that corner of the compartment. Once the runaway started, the brakemen were trapped back there. The good news is the chain isn’t going to whip through that area as it finishes running out. But things would get exciting back there if the chain jumped the capstan or the capstan seized or the chain parted.
(To “weigh anchor” is to bring it aboard a vessel in preparation for departure. The phrase “anchors aweigh” is a report that the anchors are clear of the sea bottom and, therefore, the ship is officially underway.)
