We we drop anchor (in the U. S. Navy) we calculate the amount of chain required to lay on the sea bed in order to keep the ship from dragging anchor. That is because (at least as we are taught) it’s the amount of chain that keeps the ship in place. I can’t find the exact reference that states that, it’s not in the Command at Sea book. But per the Bluejacket’s Manual, “the amount of chain to put out is usually equal to about 5 times the dept of the water.” If it was all about the anchor, I don’t think we’d pay out that much chain.
Having served on a couple carriers, but not in any way working with the anchor, all I can say is that it is weird when you are anchored out, because as it has been stated, the ship swings on the anchor, depending on the direction of the tide. So when you add the length of the carrier (1000+ ft) plus the distance from the bow to the anchor, that’s a pretty huge circle that the ship makes in the water every day. Did it in Naples several times, but I haven’t gone to sea on a carrier since my first deployment in 93-94.
Keep in mind that the carrier (or any ship for that matter) isn’t going to anchor in the middle of the ocean, even if they could. There is no reason to. I can’t remember, but I think the chains were 1,200 feet long on Coral Sea.
I guess I can imagine a situation where a huge container ship or oil tanker has to wait outside the port before a big enough dock is clear for it… some delay or whatever caused the ship already at the dock to be running late, so the huge ship has to wait outside the port for the ship already there to leave, and then wait for the port pilot to come out and guide the huge ship into the dock… anchoring would make sense in that situation. So I guess that’s one viable use for an anchor for a big civil cargo ship.
But for military aircraft carriers - huge floating cities with 6000+ crew - they operate on military schedules and are expected back at their home port at specific times, no other ship would be there at that time, so I can’t foresee the same situation happening with a huge Nimitz supercarrier.
I have a gut feeling the two huge anchors on each side of the supercarrier’s bow are really there just for aesthetics: they look really cool, so huge… they project strength in a clear but subtle way. If that’s the case then it’s a huge waste of taxpayer dollars and steel, especially since they make them functional. Why not just make them decorative/nonfunctional if it’s just for nautical aesthetics? That would save a lot of money and valuable space on the ship (those two huge chains take up a lot of space in the bow, not to mention the machines that lower and raise them). I’d love to know how many times US supercarriers have actually used their anchors in the last 20 years (excluding tests).
Two Sailors in the U. S. Navy just wrote of carriers anchoring out. And they almost always do in foreign ports. I’m an O-6 surface warfare Officer. If you don’t believe what we are writing, I can’t help you.
Oh, and spifflog can attest better to this part - every 100 feet of the anchor chain is painted a different color. I beleive that it goes red,white,blue repeating until you get to the last two lengths (shots?) which are yellow and red to warn you that you are coming to the end of the chain. From what I hear, if you see yellow, you are supposed throw the brake on, and if you see red, you need to get the **** out of there because if the anchor chain comes loose, its going to take a large portion of the fo’c’sle (sp? sorry, I’m not a Boatswain’s Mate) with it…
Ooh here we go, first-hand knowledge of anchor use on a huge aircraft carrier. WHY was the anchor used? For what purpose, in what situation? Obviously not out in the middle of the sea… How often were they used on an average mission (what, like 3-5 months)?
FWIW I’m not really looking for info re the mechanics of how anchors work. Only why/when they would ever be used on a supercarrier.
They wrote that while I was typing, didn’t see it until after i’d posted. I definitely want to hear more about what they have to say about anchor use on carriers, and of course I believe them/you. That’s the exact sort of info I am looking for.
They look like they’re freshly painted because they regularly paint them. It’s cheaper to keep a fresh coat of paint on them then it is to sandblast the rust off of them or replace the entire thing because it’s rusted beyond repair.
Nimitz is over 1,000 feet long. There are not a lot of piers that have that much space, and it they do, they don’t want it tied up with a carrier. The Navy pays per foot per day for that space, and it isn’t cheap. There is also the nuke factor, and the security factor.
As spifflog already said, we normally anchor out in foreign ports. I anchored out in Naples, but we pulled pierside in Trieste and Marseilles. This was 18 years ago, the only carrier deployment that I have done. We saw Naples twice in the six months we were out. I have also anchored out in Hong Kong onboard an Amphibious Assault ship (700+ ft long).
It is mainly about the anchor. 5 times the depth of the water allows the anchor to lay flat. If cuurrents are running high then more chain is layed out to add to the anchor.
Chain weighs maybe 300 pounds per link. An anchor weight tons.
The other point about anchors, briefly mentioned above - they are safety equipment. If the ship is fully functional anchors are useful for anchoring out, but if the ship is disabled for some reason things can get nasty quickly. A ship that is unable to make its own way becomes a danger to itself and others very quickly. There is absolutely no way that any boat should go to sea without redundant anchors capable of holding it under all conditions. We had a large carrier ground itself on the East coast of Australia in 2007 when it failed to lay anchor in the face of an incoming storm. Ships can become disabled for all sorts of mundane reasons. The combination of an on board failure, bad weather, and a nearby coast or other shipping is a situation where the only way to avoid potentially very bad outcomes relies upon anchoring. Doesn’t matter if you have eight nuclear reactors and a crew in the thousands, those anchors are not just for show. Especially in times of conflict, where there are people whose sole intent is to disable your ship.
That’s for those whose ships have a motor, and a powered windlass. I think most aircraft carriers would fall into that category.
Ok, great, thanks for the info. Looks like they do use the anchors on carriers.
The anchors and chains of Independence (CV-62) and other Forrestal-class carriers were actually reused for the Nimitz-class. Apparently there is not much about big chunks of solid iron that can become obsolete.
The Wikipedia article on anchors has some very informative diagrams about how anchors are set. They confirm that the anchor is intended to “hook” into the sea bed.
In addition to the reasons mentioned above, I’ve seen commercial ships anchor (ore haulers in Narvik harbor) while waiting for one of the few vaunted loading docks. Seemed to take several days to fill a ship with ore, so there was a small line of (huge) ships waiting in the fjord to fill up. Docking would have required tugboats and a ton of effort, and would be pointless as the ships would have to be moved again. Much easier to just lay anchor.
I was there wreck diving on ore haulers and destroyers sunk during WW2. Which was awesome.
Well, that’s fine if you have an anchor chain made of 300-pound links, as someone said. But what if it’s just a rope? Didn’t most ships use rope until a couple of centuries ago, and most smaller boats even today?
Yea obviously ropes and small chains don’t do anything about holding the ship by laying on the seabed. The wikipedia article on anchors makes it very clear that it IS the anchor that is designed to hook into the seabed… nowhere does it mention the chain/rope (technically, the “rode”) doing any of the actual holding work. Anchors DO hook into something - that something is the seafloor. Or lakefloor, riverfloor, whatever. Some are designed to work best in silty ground, some are designed for muddy water, some are designed for general sandy ocean floors. But they’re meant to dig in and hook into the floor. The “rode” is just the connector. 350 pound links on the aircraft carrier’s anchor probably do provide some friction, but compared to the size and momentum of that huge supercarrier - very little.
I think the best answer I’ve heard is about a carrier being damaged and losing power. I didn’t think of that. They’re nuclear, so the thought of them losing power - or at least thrust - never occurred to me. Obviously they’re complex machines and could break down for a billion reasons, never mind being hit during an actual war. Being close to a coastline would necessitate using the anchors to prevent the carrier from running aground. That makes great sense.