Ground tackle and the anchor windlass

What the rule requires

Follow the chain and the whole system orders itself: it leads out of the chain locker, up through the spurling pipe, over the wildcat of the anchor windlass, through the hawsepipe, and out to the stockless anchor stowed in that hawsepipe NAVEDTRA 14067 §4-3. Every fitting and every command in this topic sits somewhere on that path, and a question that names a component is usually asking where on the path it lives and what it holds.

Two things hold the anchor and chain when the windlass is not heaving: the brake on the wildcat, and — more securely — a chain stopper, a pelican hook or riding pawl that takes the strain off the windlass while the ship rides to her anchor. That ranking is the single most heavily tested point in the topic. The stopper is verified as the load-holding device precisely so that the windlass brake is not the sole holding device when riding to anchor NAVEDTRA 14343 §4-3.

The windlass and its parts

The anchor windlass heaves in and pays out the chain and holds the anchor at the hawsepipe. Its principal parts are the wildcat, a notched sprocket-like drum whose pockets, or whelps, are shaped to grip each link of chain; the wildcat clutch (locking head), which connects the wildcat to the drive shaft; the brake band, which controls the wildcat when it is declutched; and the prime mover, electric, hydraulic, or steam. Most windlasses also carry gypsy heads (warping heads) on the shaft ends, and those are for mooring lines, not chain.

To let go: with the wildcat declutched and the brake holding, the riding pawl or devil's claw and any chain stopper are removed, the brake is then eased, and the anchor runs out under its own weight, the brake controlling the rate and stopping the chain. To heave in: clutch the wildcat to the drive, release the brake, and the windlass walks the chain back aboard while a hand hoses mud off it and reports the direction and tension — "up and down," then "anchor's aweigh," then "clear anchor" .

The ship is riding to two shots in a rising breeze. What is holding her, and what would you check first?

The chain stopper — pelican hook or riding pawl — should be passed and carrying the strain, with the windlass brake set but not relied on as the sole holding device. First check is that the stopper is in fact bearing the load and the brake is in a known position; the brake lining and band are also checked for wear and grease-fouling .

Chain: shots, links, and markings

Anchor chain is measured in shots, each shot being 15 fathoms, 90 feet NAVEDTRA 14343 §4-1. Shots are joined by detachable links — a two-part link secured by a tapered locking pin and a lead plug — so a damaged length can be cut out and replaced rather than the whole cable condemned. Each detachable link and the adjacent chain are painted, and the links wire-wrapped, to a colour code, which is how the crew reads how much chain is out as it passes the wildcat.

Anchors and where holding power comes from

The stockless anchor is standard on most vessels because its crown and pivoting flukes let it stow snugly in the hawsepipe. When it is let go and the ship drags astern, the flukes trip downward and dig in; holding power comes from the flukes biting the ground, not from the anchor's weight alone. Older patterns are the old-fashioned (stock) anchor and the lightweight (Danforth) type, whose large pivoting flukes give a high holding-power-to-weight ratio.

Appendages and the bitter end

The bending shackle joins the chain to the anchor. The swivel prevents turns building in the chain as the ship swings, and the mooring swivel is used when riding to two anchors. At the other end, the bitter end of the chain is secured in the chain locker by a clench or a quick-release pelican hook so it can be slipped in an emergency.

Inspection runs to worn or elongated links, cracked or distorted detachable links, missing locking pins or lead plugs, worn flukes and shackle pins, and legible chain markings — a marking a hand cannot read is as good as no marking when chain is running. Shackle pins are moused, and turnbuckles locked, to keep gear from working loose under vibration and load reversals NAVEDTRA 14343 §8-3.

Cargo winches and cranes

Cargo winches, whether driving a boom runner or built into a crane, are electric, electrohydraulic, or steam, and their brakes must hold the rated load automatically when power or control is lost NAVEDTRA 14343 §9-4. The safety devices are a load or overload indicator and cut-out that prevents lifting beyond the SWL, limit switches that stop the hook before two-blocking and stop luffing and slewing at the ends of travel, and a slack-rope or anti-two-block warning. Brakes and limit switches are tested at the start of the watch; the hoist wire is checked for broken wires and even spooling, with the required dead turns retained on the drum. Never override a cut-out to force an overload, keep clear of the slew radius, and pass no load over personnel.

Telling it apart

The criterion that separates the parts around the windlass is what each one engages and when it takes the strain.

Wildcat — engages the chain itself; its pockets, or whelps, grip each link. It is what the chain passes over, and it is where the markings are read as they go by NAVEDTRA 14343 §4-3.
Gypsy head (warping head) — engages mooring lines, on the shaft ends. It never handles chain, and it is the fitting most often wrongly named as the chain wheel in distractors.
Wildcat clutch (locking head) — engages nothing external; it connects the wildcat to the drive shaft. Clutched in to heave, declutched to let go.
Brake band — controls the wildcat when it is declutched, and is the device that regulates the rate the anchor runs out and stops the chain.
Chain stopper (pelican hook or riding pawl) — takes the strain off the windlass while the ship rides at anchor. Passed after the scope is veered, removed before letting go.

The connecting fittings

Here the criterion is what two things the fitting joins.

Bending shackle — chain to anchor NAVEDTRA 14343 §4-1.
Detachable link — shot to shot, in two parts secured by a tapered locking pin and lead plug.
Swivel — inserted so twist cannot build in the chain as the ship swings.
Mooring swivel — the fitting used when riding to two anchors, not the same item as the swivel in the ordinary outboard chain.
Clench or quick-release pelican hook — bitter end to the chain locker structure, arranged so the chain can be slipped in an emergency.

Working a question

A ship is ordered to anchor in 60 feet of water, port anchor, four shots on deck. Work it as the forecastle would.

Walk the anchor out clear of the hawsepipe with the windlass paying out under power, so the anchor hangs free and nothing binds when the brake is eased NAVEDTRA 14343 §4-3. The decision here is that the anchor must be out of the pipe before it is let go, not dropped from the housed position.
Wait on the bridge to take the way off the ship NAVEDTRA 14067 §4-3. Chain veered while the ship still carries headway runs out ahead of the windlass rather than under control.
Declutch the wildcat, with the brake holding. Clutched in, the chain cannot run out under the anchor's weight; the drive would be fighting the fall.
Remove the riding pawl or devil's claw and any chain stopper. Nothing that holds the chain may remain rigged when the order is given.
On "let go," ease the brake. The anchor runs out under its own weight, and the brake is the only thing metering it — surge it to control the rate and set it to stop the chain.
Read the markings as they pass the wildcat and report shots out, plus the lead and tension of the chain. Four shots is 4 × 90 = 360 feet of chain against 60 feet of depth, which is scope of several times the depth of water — the order of scope the evolution calls for NAVEDTRA 14343 §4-1. The lead and tension reports are what tell the bridge whether the anchor has dug in as the flukes trip.
Pass the stopper and let the ship ride to it, so the strain comes off the windlass.
Weighing, reverse it: clutch the wildcat in, release the brake, heave, hose the mud off as the chain comes aboard, and report "up and down," "anchor's aweigh," "clear anchor" .

Throughout, keep out of the bight and out from between the chain and any fixed object, and keep the spurling pipe and chain locker clear so the chain stows without piling and jamming.

Where candidates lose the point

Answering that the windlass brake holds the ship at anchor. It is on the list of what holds chain when the windlass is not heaving, so it looks right. The stopper is the more secure of the two and is specifically what takes the strain off the windlass while riding.
Converting a shot wrong. A shot is 15 fathoms; the trap answer is 15 feet, and the near-miss is 90 fathoms. Fifteen fathoms is 90 feet, so four shots is 360 feet.
Crediting holding power to the weight of the anchor. Weight sets the flukes, but the holding comes from the flukes biting the ground after the ship drags astern and they trip downward.
Calling the gypsy head the chain wheel. In North American usage the chain runs on the wildcat; the gypsy or warping head on the shaft end takes mooring lines.
Letting go with the wildcat clutched in. Distractors describe the let-go sequence with the clutch engaged and the stopper still on. Declutch first, strip off the pawl and stopper, then ease the brake.
Confusing "up and down" with "anchor's aweigh." Up and down is the report that the chain is vertical; aweigh comes after, when the anchor has broken out; clear anchor is the last of the three.
Placing the bitter end outboard. The bitter end is the inboard end, secured in the chain locker by a clench or pelican hook so it can be slipped.

Check yourself

You are the forecastle petty officer and the ship has just veered five shots in a crowded anchorage. What must be done before you report the ship riding to her anchor?

Pass the chain stopper — the pelican hook or riding pawl — so it takes the strain off the windlass, then set the brake. The stopper is the holding device; the windlass brake must not be the sole one while riding NAVEDTRA 14343 §4-3.

Six shots of chain are out. How many feet is that?

540 feet. A shot is 15 fathoms, and 15 fathoms is 90 feet, so 6 × 90 = 540 NAVEDTRA 14343 §4-1.

Your anchor has been let go on a hard sand bottom and the ship is drifting astern with the chain slack. Why does the anchor eventually hold?

As the ship drags astern the pivoting flukes of the stockless anchor trip downward and dig into the bottom. Holding power comes from the flukes biting the ground, not from the anchor's weight alone — which is why sternway on the ship is part of setting it.

You are told to take a mooring line to the windlass. Which part of the machine do you use, and what must not go on it?

The gypsy head, or warping head, on the shaft end — that is the fitting provided for handling mooring lines. Chain goes on the wildcat, whose pockets are shaped to grip each link .

Heaving in, the chain leads straight down and has not yet broken ground. What is your report, and what comes next?

Report "up and down." When the anchor breaks out of the bottom the report is "anchor's aweigh," and once it is sighted and free of the bottom and of any fouling, "clear anchor" NAVEDTRA 14067 §4-3.

Inspecting ground tackle before sailing, you find a detachable link with the lead plug missing. What is the significance, and what else on that list would you check?

The two-part detachable link is secured by a tapered locking pin and a lead plug; a missing plug is an inspection defect because the pin can work out and the shots part. On the same round check for worn or elongated links, cracked or distorted detachable links, worn flukes and shackle pins, and chain markings still legible .

A cargo winch loses power with a load on the hook. What is required of the brake, and what would you have tested at the start of the watch?

The brake must hold the rated load automatically when power or control is lost. At the start of the watch, brakes and limit switches are tested, the hoist wire is checked for broken wires and proper spooling, and the load indicator or overload cut-out is confirmed working NAVEDTRA 14343 §9-4.

The ship must clear the anchorage immediately and the anchor is fouled beyond recovery. What arrangement allows the chain to be let go entirely?

The bitter end is secured in the chain locker by a clench or a quick-release pelican hook, arranged so it can be slipped in an emergency .