Anchor and cathead

A windlass is a type of winch. A capstan is a revolving cylinder for use in a winch. Same thing, just different names. Capstan is the more commonly used one for the anchor. Poles were inserted against which the sailors pushed, walking slowly around the capstan. Cogs would hold the anchor in place as it was raised.

Cathead provided the lower support against which the anchor rested. Anchor was then lashed into place during voyages. If the lashings broke, the anchor would then start swinging from the anchor chain. One side of a ship would be windward, and the anchor would swing out. The other side of the ship is leeward, and the anchor would swing in. (This is due to the heeling action of a sailing vessel.)

The swinging back and forth is the problem. As you go over waves, and wind pressure changes, a swinging object gyrates in different planes. In certain positions, it bangs against the hull. Give it some time, and it will hammer its way through the hull. That's the danger of the anchor breaking loose.

Were the cogs to let loose at the same time as the anchor broke loose would result in the anchor dropping, running out the anchor chain (or more like a cable or rope). If the anchor chain is not tethered to the ship, it would just run out and you'd lose the anchor. No big deal. If the anchor is tethered to the ship, in deep water it would hit the tether and stop, and you'd have to winch it back up. It would be only if the anchor dropped and grabbed the bottom that you'd have problems. Depending upon the wind and speed of the boat, totally wrecking the boat is a big probability.

Best of luck,

Jim Clark-Dawe

Here is a link to a page with some photos of an accurate model of the HMS Victory's anchor capstan and associated equipment. Please note the relative distances (plus most of the capstan being below decks) that you need to take into account for any action sequences you are writing.

Note, a competent crew would tie the anchor off, just in case. Even on a modern boat, the mechanism for winding the anchor can skip in a storm or if it takes a shock. I'd imagine it would take quite a shock to knock the anchor chain off the teeth on that size of ship, but it could happen.

Also, AFAIK, the cathead would not have to break for the anchor to fall. It's only to keep the anchor off the hull, not stop it from playing out, but I am no expert on old-timey ships.

You're making this a lot more complicated then you need to.

The anchor is held in place by lashings and the last pawl used in lifting the anchor. Release the lashings, let the last pawl go, and the anchor will slide right down. That's what it's designed to do when anchoring. Lowering the anchor is simply a matter of letting the anchor drop. You might restrict the speed it plays out at, but the phrase "dropping your anchor," means exactly that.

Cutting the lashings involves hanging over the side of the ship, so you get some action there.

Best of luck,

Jim Clark-Dawe

Note: If the anchor is meant to catch, please don't have this scene take place in the middle of the open ocean. In a book I'm reading now a ship was anchored out of sight of land with no explanation. There is a finite amount of chain you can carry and open ocean is generally very deep.

From Duncan's wonderful link, 120 fathoms (720 feet) of anchor cable weighs 7 tons. That would be about the limit of what you'd want for cable. With that length, you can drop an anchor in about 150 feet of water and stand a reasonable chance of staying put in good weather. (Bad weather requires that you lay out more cable. The flatter the cable is to the ocean bottom, the better it will hook.) Depending upon how the floor of the ocean shoals, 150 feet of water might be 150 feet from shore.

Anchoring in deep water is done using a sea anchor, which is an entirely different thing. It doesn't really anchor you, but limits how much you drift and the orientation of the boat.

Best of luck,

Jim Clark-Dawe