It's time once again for our regular open thread. Talk about whatever you want, so long as it isn't Culture War.
Don't have a whole lot to say today. Hope my American readers had a good Thanksgiving. Remember that the USNI sale is still ongoing.
Overhauls for 2017 are Lissa, The Battleships of Pearl Harbor Part 3, Iowa parts five and six, Mine Warfare Part 1 and Russian Battleships Part 1. 2018 overhauls are Falklands Part 8, Commercial Aviation Part 1, Missouri Part 3, Internment, Crew Art aboard Iowa and SYWTBABB - Design Part 2. And for 2019, I looked at Billy Michell Part 1, The Navy and the Space Program, Falklands Part 19 and Harpoon.
Comments
Touching up on a couple of things from OT64:
On anchoring: still pretty common. On my last deployment (though on a hospital ship, FWIW), out of 10 port visits, 4 of them were anchored out. On destroyers, I think it ended up being about 1/3rd of PVSTs were at anchorage (some memorable anchorages including Lagos, Nigeria, Dili, East Timor. and Bali, Indonesia). Was much more common in the Pacific than in the Med.
You will often anchor out at your smaller ports because they don't have either the depth of water pierside, or the piers are too small/not outfitted to support your ship. Or you're with the carrier and the carrier wanted to go pier side, and thus, you got to go pier side).
And as far as riding out a storm, in Dili we got caught in a storm with gusts going to 60+ mph and held fine. That was a fun day of duty.
You can also moor to a buoy (which in my mind was always what you did in Hong Kong), which involves disconnecting your chain from your anchor and then connecting the anchor chain to the buoy itself (most big harbors have designated mooring buoys).
Fun fact! It's the weight of the anchor chain vice the weight of the anchor itself that holds the ship in position, so if you've got a storm coming in, you'd pay out more shots of chain to hold you in position.
On the design concept of SSGNs: note how the Soviets thought about them, though. From the design of things like the Projects 659/675, 670, and 949s, it's clear the Soviet thoughts on SSGNs were basically "Missile carriers to attack CVNs, but submersible).
CV Maintenance: it's complicated. For one, there's actual law that limits what level of maintenance you can do outside the US (to force business back to US shipyards). That applies to all ship classes.
For another, since all our carriers are nuclear, there is a bunch of maintenance that has to be done at select, nuclear-capable shipyards (specifically Puget Sound Naval Shipyard and Newport News Naval Shipyard. PSNY has a det in Yoko to support the carrier there).
And finally, there's the issue that to set up a maintenance facility, you need a lot of space and an existing ship facility, and you need to have a fairly skilled local workforce to hire from (since you have to hire lots of locals, or else plan on paying ridiculous costs to bring in guys from America). Pure physical security isn't as much of an issue as might be thought (though it's a factor). So in a place like Taiwan, or Singapore, that shouldn't be as much of a problem...but it in a less developed place like the Philippines, you're not going to have as many skilled guys to hire from. Heck, even in Japan, we had problems; I recall one shop at SRF Yokosuka had an issue where they were down to one really qualified guy, and he was in a wheelchair. So they had to rig up chainfalls and lower him and his wheelchair into the space, and then they had a bunch of journeymen to do the work under his supervision. It was pretty surreal. So that's a major limitation to where you could put a new base to put ships.
TIL about the Bevin Boys, UK conscripts during WWII assigned to work in the coal mines. There were nearly 48,000 of these young men, who were chosen by lot. Most were general conscripts, not conscientious objectors. The last of them weren't released from service until 1948.
What a way to fight a war. I think I'd take permanent latrine duty over service in the mines, particularly with mid-century safety practices.
@Blackshoe
Is there a rule of thumb for what the weight of the anchor chain needs to be to hold the ship in, or nearly in, place?
You mention paying out more chain when a storm is approaching. How does one determine how much extra is needed?
...Some details about the ultimate fate of PENNSYLVANIA and NEW YORK:
*PENNSYLVANIA never did get a fire control solution at Surigao Strait but the cause is unclear. I've seen fouled range and malfunctioning radars mentioned as causes, but never seen anything definitive. And she was in awful shape when she went to glory at Bikini; apparently she was still shipping water.
*Your footnote about NEW YORK - have seen a couple sources state that the USN actually approved NEW YORK as a memorial (the state very much wanted her) but that would be done only if she could be cleaned up afterwards. There may be some truth to this as she was towed back to Pearl after the Baker test in July '46. Evidently the USN studied her pretty closely but obviously nothing could be done and she was sunk as a target in July of '48.
I'd never heard that she was considered for a memorial after Bikini. The book I have on Crossroads doesn't mention anything about that. As for Pennsylvania at Suriago, I'd have to check Tully's book to see what he has to say.
@Neal
Not Blackshoe, but my books say that 5 to 7 times the depth of the water is normal when anchoring. Nothing about adding chain in heavy weather. They indicate that you'd set a second anchor.
Looks like someone got through the spamfilter.
Also looks like I should refresh before commenting on the spamfilter.
It's fine. Someone had. And now the site they were linking to is on the banned word list. This is now policy.
@bean,
For what it's worth, I believe the 5 or 7 to 1 chain length to depth ratio comes from the optimal angle to drag the anchor on the bottom, rather than the weight term of the anchor - basically because its the same rule we use for a 25' sailboat. Sailboats generally recommend having 15-20' of chain attached to the anchor, but then switch to line in order to cut down on a)the amount of weight the poor guy up from has to haul up and down and b) putting too much weight in the front of the boat and messing up the boat balance. A proper ship will have gone to a winch for paying out the anchor (most sailboats over 40' or so do so too), and don't have the same magnitude of balance concern, so can go to all chain.
As I've always understood anchor forces, the weight of the chain is to act to minimize the amount of upward force on the the anchor itself - but the vast majority of the anchoring force comes from the anchor biting into the seabed (or the weight of the anchor acting to create friction on the seabed if you go to an ancient anchor design...either way the anchor dramatically looses effectiveness if your boat is imparting vertical forces on it), but how well that scales from boats to ship is outside of my ken.
So the FAS and other usual suspects are getting pissy about the Navy's Life of Ship reactors. Is this just because it would get in the way of eliminating the last of our highly enriched uranium use?
The concept seems absolutely awesome to me, and it's a pity it can't be applied to small land-based reactors in special duty stations.
Being maximally cynical, refuelings cost a ton of money, so Life of Ship reactors are significantly cheaper than earlier types over the vessel's life. This makes nuclear power more attractive, and that means it might get used more often. Which is contrary to FAS's goals.
It looks like they've decided to decommission the USS Bonhomme Richard: Navy Will Scrap USS Bonhomme Richard
I am extremely not surprised by this. Figured it was good odds from about day two of the fire, and if anything, I'm just surprised it's taken them this long to call it.
You too can now catch Secretary of Defense Espurr in Pokemon Go raids!
From an engineering point of view, a Life-of-Ship reactor also means that you have more freedom when designing the ship, because you don't have to allow for the change over.
Not that I've ever designed a nuclear ship. But I have designed a number of machines with things like filters or motors in them. And it's often well worth the cost to use a much bigger and more expensive long-life part just so that you don't have to leave a path through all the pipes and bulkheads and seals to allow someone to get in there and change it.
Of course you still need to get the reactor out at the end of life. (Unless you're Russian and can just sink the entire obsolete nuclear ship into the deep ocean?) But at the end of life you have no problem with just cutting through all those pipes and seals and bulkheads.
That's been banned.
On your other point: with life of ship reactors you'll have no choice but to use parts that can last the life of the ship inside the reactors.
The spam is starting to drive me slightly nuts, and I'm considering more extreme solutions for it. One option would be requiring an account to comment, but that's probably going to mean setting up an automated way of creating accounts. Another is banning the word "essay", which would take care of the current spam, but might not work long-term. I'm definitely interested in preserving the comments, so don't worry about that. But does anyone else have suggestions?
My first thought is by-IP greylisting, where the first comment from a given IP address goes into manual moderation, and, if approved, all future comments from that IP go through. Of course, that has all sorts of problems, VPNs and proxies foremost, and might not actually stem the tide of spam.
I think it's probably hard to avoid needing registration, or at least some kind of unique identifier.
Another option is to go back to the system we used in the first months of the blog, where I had to manually approve comments from anyone who didn't have an account, and just set up accounts for frequent commenters. A fair number already have them, and for those that don't, it's just a matter of emailing with the username (no spaces) and password you want.
Would it be possible to include a more sophisticated CAPTCHA system (like ReCaptcha or hCaptcha(https://www.hcaptcha.com/))?
In other news, the Israeli Navy received the first of its Sa'ar-6 corvettes, and unlike most modern vessels these ones are actually somewhat aesthetically pleasing to look at.
@quanticle, I don't mind the Sa'ar-6 look at all. Extremely minimalistic. If it wasn't for the black marks (soot?) on the sides you'd think it was a screen capture from a video game.
No visible weapons? Not even a machine gun on the deck?
Given that what few spams I've seen have had misspellings maybe just run everything through a spell check and require manual approval for anything not spelt perfectly.
What kind of idiot would buy academic cheating services from people who can't even use a spell check?
@Doctorpat Maybe it hasn't had all its systems installed yet?
Having checked Wikipedia, they're supposed to have a 3" gun, presumably on that octagonal mount ahead of the (forward/only?) VLS. I think I've read somewhere (here?) that Israeli ships are often very heavily equipped for their size, so it'll probably look more cluttered with all its kit. I guess when you operate in the Med heavy seas and stability aren't something you have to worry about so much.
Interesting that they are German built. I wouldn't have thought Germany would be a popular place to buy your warships from, but apparently the Israelis get a very nice (reparations related?) discount.
@Anonymous
That's a good question, and I've wondered the same thing myself.
@Alexander
Germany has been a pretty serious warship exporter since the mid-Cold War. The MEKO design was an early modularized ship platform, and got a number of customers.
As for stability, I've heard some truly horrible things about Israeli ship design practices in that regard. There's a good chance it was here.
A friend of mine has requested a book recommendation on the space program. Her criteria is "the most important book about space". My initial thought was a comprehensive and critical history of the shuttle program, but I'm not aware of a good one. I'm open to other topics, but don't have a lot of great space books handy. Any suggestions?
If you want the best history of the shuttle program, you want Jenkins. On the other hand, that is a terrible choice for someone who has asked that question because it's very dense. I might go with Chaikin A Man On the Moon, which is a good and readable history of Apollo.
@doctorpat @Alexander
I don't think the ship has had all its weaponry installed yet. From what I can see, it's missing the CIWS systems, the deck gun, some machine gun mounts and the torpedo launchers. The IDF has shown off a model of a completed Sa'ar 6-class ship, and I think it still looks pretty. Even with everything installed, it's still a very clean looking design.
@cassander
This might just be my personal bias showing, but I the most influential book about space for me was Diane Vaughan's Challenger Launch Decision. Diane Vaughan goes deep into the engineering practices at NASA and shows how the organization became blind to the creeping problems that would culminate in the decision to launch Challenger on that fateful day in 1986.
@Doctorpat
I think one of the concerns with the life-of-ship concept is basically related to what you're saying: If you don't have to refuel the reactor, it is far more appealing to minimize user-serviceability. Since the ability to inspect tends to go hand-in-hand with serviceability, you end up at risk of a problem that might take 20+ years to develop that you have no way of noticing because there's no access. Honestly though I'm not sure this problem would be any more serious for LOS reactors than for the reactors in the Virginia class that are expected to go 33 years without refueling.
If 33 years isn't "life of ship" for the Virginia-class, what is? Are we expecting to keep these boats around for 50 years?
Both the Seawolf and Virginia classes have life-of-ship reactors.
@cassander
Try Ignition! by John D Clark. Just reprinted, but also available free at
http://www.sciencemadness.org/library/books/ignition.pdf
Its the history of liquid propellants, written by a PhD who was also a pulp fiction author back in the day.
At the same website you can also find Max Gergel's classic "Excuse me sir, would you like to buy a kilo of isopropyl bromide?"
@bean It's probably entirely unreasonable prejudice, but Germany's reputation for excellent engineering doesn't extend to their warships. I'd pick Danish or Dutch over Deutsch, unless given a compelling reason (like a 1/3 discount).
@quanticle I don't think those are torpedo launchers. I'm guessing they're Harpoons, or the Israeli equivalent (maybe with a land attack capability).
@Alexander
I'm kind of with you there. Given the issues with the Brandenberg class, I would be hesitant to buy from them right now. But the British would probably be happy to sell Type 26s, and those look really good.
As for the Saar VI, those are definitely missile launchers. There's also what I think is some form of countermeasure atop the bridge, but I'm not sure what.
It'd be great for Britain to get an order for an extra four type 26 frigates, but Israel really doesn't need anything that fancy. If they were buying British something more like a Khareef would be my pick.
Pretty sure those are DESEAVER MK mounts port and starboard on the bridge and abaft the aft stack.
I tried reading "Ignition!", and after two chapters I am ready to conclude that it is a well written book aimed at a very specific audience, and that audience does not include me.
A representative sequence:
@Johan Larson
I tended to skip over the maths bit and focus on the bangs...
IRL my profession has nothing to do with science - especially rocket science - but I remember enjoying it enough.
I loved Ignition.
But then my wife calls me insane when I read in bed and laugh at the funny bits in micro-mechanical engineering reference books.
Yeah. I tend to skim the parts where he talks a bunch about the technical details of chemistry, and focus on the bits where he tells amusing stories about stupid propellant ideas.
Skip the engineering, read it for the "and then we seriously considered firing a mercury rocket in a test cell in Northern New Jersey till they caught us at it"
It's a constant source of reference in Derek Lowe's (not hte baseball player) "Things I won't work with" series.
What's the wimp option in liquid rocket propellants? Suppose you want something that's safe, cheap, and easy to work with, but you're willing to take a hit in performance. What do you use then?
Johan Larson: A hydrocarbon fuel with Lox or Nitrous Oxide (N₂O is a bit expensive (and looking up how they make it amazes me that chemical plants don't blow up constantly), and Lox is cryogenic, there don't really seem to be any nice oxidizers).
Nox is by far the safest of the oxidizers. It's non-cryogenic and reasonably non-toxic. Nothing else comes close. Lox in particular is really nasty stuff to deal with.
N2O being the "safe" oxidizer for entry-level rocketry was the conventional wisdom before 2007, but Mojave changed that.
https://www.space.com/4123-explosion-kills-mojave-air-space-port.html
According to people I know who have worked with it, liquid N2O is extremely sensitive to even small levels of organic contamination, and the susceptibility to boiling liquid-vapor explosions puts it over the top into solidly dangerous territory. Gaseous N2O at modest pressures is tolerably safe, but doesn't have the storage density to be interesting in rocketry.
Liquid oxygen probably is the easiest and safest oxidizer to work with if you don't have a requirement for long-term storability.
In my circles, mono propellant hydrogen peroxide is probably the best candidate for "shitty performance, but at least it's easy to handle". Note that this is by orbital (or at least suborbital but still going to space) rocketry standards, while I think John Schilling is referring to the hobby rocket communities standards, which can make another level of sacrifices on performance.
Worth repeating anytime someone asks "isn't there something less toxic we can use even if it takes a bit of performance hit"......If you want to go to space, the tyranny of the rocket equation means that taking that performance hit is going to exponentially reduce the performance of your system, and if you want to use something truly non-toxic you probably aren't going to space*.
*From earth anyways, you can do all kinds of interesting things for in-space thrusters at lower performance since they tend to be dominated by the problem of long term storage more than propulsive efficiency. Since most people in the space business work on the satellite side rather than launch vehicle side, that means for most workers that might be a reasonable trade....but if you want to be in launch vehicles forget about "safe" propellants.
All this talk about propellant brings to mind the famous Man from Lox safety video (don't think that's the full version, also, amusingly, it's probably NSFW in today's world).
Also, this discussion about propellants (starting off with discussions about NASA and the space program) brings a rather Hot-Take-y opinion if mine, which is that NASA is MASSIVELY overrated and praised culturally.
@Neal:
There is no specific rule for how much chain you need to pay out that I remember (and it appears I purged all my OOD notes in a recent round of basement cleaning). One thing to keep in mind is that the more chain you pay out, the more your drag circle increases, so you'd want to make sure that stays away from any dangers. And also that you don't have to pay out any more chain until you can see that the chain you've already paid out isn't holding (eg you're dragging anchor).
@bean: at least on a DDG, you can't actually drop another anchor, because there's only one chain. There are two anchors, but to use the second, you need to switch out the chain.
Finally, here's a fun video of USS TARAWA losing her anchor chain (around 4:30 is where it starts getting really fun!)
Random thought apropos safe rocket propellants: what would happen if some country (e.g. say France) one day decided to fly a nuke-thermal ship? Would the US and/or any international agency step in and prevent them? Or is the idea too far-fetched to even consider?
Really, isnt a prerequisite for a successful essay writing service a working spell check function?
@John
I find it weird that Nitrous Oxide could have gone from "by far the safest" to "unacceptably dangerous" in a single explosion, much less one that waited until 2007 to happen. That was, what, 60 years into the liquid propellant rocket age. If it took that long to happen, then it can't really be that dangerous, can it?
@AlexT
There's no international regulations against doing such a thing. I looked at it moderately seriously in college for a cubesat competition, and even got to the point of asking NASA about it. Weirdly, they said yes.
@Blackshoe
I wouldn't disagree with you at all re NASA.
@Manly Reading
Yeah, but they don't seem to have gotten the memo.
Wait what, you can put a nerva on a cubesat? Or was it a fission-fragment rocket or some such?
Thanks Blackshoe and Bean for the replies on the anchor chain.
Blackshoe- that was indeed an interesting video with impressive specs listed at the end. I can only imagine the "chat with tea and biscuits" that someone had with the Skipper after this and/or that the Skipper himself had with the command authority.
@Alex
No, it would have been NERVA-like, with water as both moderator and reaction mass. We thought it would work, but then the nuclear people double-checked their math and found that they'd made a mistake in the first batch of calculations. We also ruled out RTG thermal because they couldn't provide enough heat without melting the cubesat during handling. Asked NASA anyway in case anyone had a brainstorm.
So it appears that there's trouble brewing in Washington. President Trump has threatened to veto the 2021 NDAA because it doesn't repeal the safe-harbor provisions of Section 230. There's strong support on both sides of the aisle for an override if he does. This is an important piece of legislation, and I hope it goes through quickly, whatever happens.
So what happened with that anchor chain anyway? Was it operator error? Mechanical failure?
@bean: 2007 may have been 60+ years into the liquid rocket age, but for almost all of those years nobody really tried nitrous oxide - at least nobody who was documenting their results or being paid attention to at more than the "darn kids burned down the barn again" level. I don't think it's even mentioned in Clark, for example. The first serious use was SpaceShip One, 2003-2004.
The 2007 explosion prompted people who aren't risk-tolerant hobbyists to seriously address the question, "can we extrapolate from N2O's safety record in e.g. dentists' offices to the conditions encountered in rocketry?", and the answer turned out to be no.
There are still people who use it in rockets, some with legitimate reasons. But the procedures you have to follow to use it safely, are no less stringent than those for e.g. LOX. Sixteen years later, we're still waiting on SpaceShip Two.
On the anchor chain, it looks like operator error to me. The chain got snagged, so they backed off the brake, and then it came unsnagged and built up enough momentum that they couldn't stop it. Looks like they had a rookie officer supervising two inexperienced sailors and nobody noticed the problem until it was too late.
I've actually watched a bunch of old military training videos posted by periscope films, and I 've come away marveling at just how informative and memorable they are. (I particularly enjoyed "Castaway" the WWII naval sea survival one.) It has led me to the conclusion that sometime around the 70's we lost the capability of making good short, educational films. Somehow more modern training films just fail at some deep level- they aren't captivating or memorable, and the messaging is comparatively garbled. It seems to have something to do with the transition from film, but I have no idea what the root cause would be. A lower level of training for the filmmakers? Less effort put into scripts? Higher volumes and lower profit margins driving competent production companies out of the business? I'd love to know what exactly happened.
N₂O is also too expensive, at least if you're looking at the possibility that propellant cost will matter though someone following precautions comparable to Lox should be able to handle it safely.
That no one even tried until relatively recently is strange, the performance with hydrocarbons isn't that bad and it is space storable and they tried peroxide which Ignition has convinced me isn't viable but Ignition didn't convince me that N₂O shouldn't be used (but the idiots proposing a blend of N₂O and hydrocarbon as a mono-propellant…).
On nuclear rockets, international law does not ban them, in fact the only part of international law to directly address it that I'm aware of is a non-binding resolution of the GA stating that since nuclear is needed for some space activities it needs to be allowed but that those who do it need to do it safely.
The liability convention doesn't say anything about nuclear but it would apply if someone who launched a nuclear rocket caused damage to a country other than their own.
There's always the option of a hybrid Inconel/Lox fuel mixture. Burns a lovely green colour.
Inconel? That's a superalloy, and if it's the fuel for your rocket engine, there's something that has gone horribly wrong.
"Inconel? That’s a superalloy, and if it’s the fuel for your rocket engine, there’s something that has gone horribly wrong."
Says someone who watched today's Starship test flight :-)
OK, from the green color it was probably copper rather than Inconel that was doing the burning there.
Yeah I checked and the regenerative cooling ducts are milled from copper inside an SX500 shroud. Makes sense since fuel flow problems will make the cooling less effective as well as making the exhaust run oxygen- (then engine-) rich.
Ah. I was not aware of the accident. I think even Elon Musk would agree that inconel is probably not a good choice for rocket fuel.
I absolutely love Elon Musk's willingness to blow stuff up in the pursuit of progress. It's not just that it shows the focus on rapid iteration and a valuation of time vs. material, but it also shows how good he is at managing expectations. If you look at his twitter he's all positives-you would think they made orbit rather than lost the prototype, and he's not wrong: they got what they needed from the flight and there's a good chance they never would have flown that setup again. Normally people would seize on a prototype test explosion like yesterday's but by relentlessly focusing on progress made he never gives them a chance.
Move fast and break things is usually a software development mantra