In a yard period late last year, Freedom acquired two large oblong metal boxes on its transom, on either side of the stern gate its crew uses to launch and recover boats. The sailors call these “buoyancy tanks,” although they look almost like a baby’s water wings for the pool — or, yes, there is a more explicit anatomical parallel to be drawn. Think about it.
I wonder how that impacts the stern RCS - you know, when LCS is "running away" as per the CONOPS? Just saying ... he has more on what this means for LCS-3 here.
Sims would not be pleased.
.... and yes; LCS-1 now has a ship's song - they can play it while UNREP'n every 48hrs.
31 comments:
If it is truly the case that these "cofferdams" or "blisters" (which essentially is what they appear to be) were installed to create additional buoyancy, this LCS-1 design is likely doomed to get the down-vote from Big Navy. This smacks of a lack of an ability for future growth - how will future systems be accomodated? Fine by me, I like the LCS-2 design better anyway. Seems much more useful.
If you wanted extra bouyancy, this is a weird place to put it. I just have to wonder if they have something to do with the pump jets. They're just too damn high, and if actually used for bouyancy, would tend to put the bow down.
Warts and all.....
I didn't get the song at work, but I'm guessing "My Hooptie?" :)
Dunno, not a naval architect but those things only add weight until they start to get submerged. I can only think of a few situations those will do anything (OK, 1 more if thast is where the RPG hits - Forrest did get shot in the buttocks) : 1) Holeshot/Hard reverse - and if that is the case she is no ballerina 2) Hard turns kicking the outboard @$$ end hard over, not likely 3) Following sea 4) she corskscrews something fierce in a beam sea. I alway thought the rub was she rode bow low / stern high.
If they were submereged all he time they would serve different purposes / situations...
OK, just RTFM'd (or more accurately RTFA'd). Reserve Bouyancy.
I had a chance to think about it, they might be because of high speed runs and LCS doesn't plane like it should. It's the only thing I can think of that makes sense.
I once saw the USS Bainbridge DLG(N)-25 peel away from an UNREP making a roostertail. That was impressive!
The rear view of this critter - not so much.
But she would really need to squat for that to have an effect. Before those steel cheeks can have <span>any</span> benefit they need to submerge enough air under water to offest their actual weight - no benefit occurs until that point. So under what conditions will take place having the stern down by at least 10 feet?
I don't know, but I do know it's a stupid place to place extra bouyancy tanks. Then again, there isn't much smart I've seen on LCS.
I like to call them "bustles" ?~~ LOL. and they ARE for reserve bouyancy in a damaged stablity situation as are the INTERNAL bouyancy tanks I saw up on Freedom's mid-mission deck bulkheads.
Yes there are concerns about the LCS-1's RB & DS. Supposedly that will be "corrected" in the LCS-3 and who know what LM will offer in for the current RFP.
Suffice to say that RB & DS are a significant concern.
Another thought abou the bustles is how will they impact boat ops? I would suspect that while launches in SS4 might be easier, recoverys will not?
Lee, after thinking on this, there ain't no way, NONE, that you put a bouyancy tank ABOVE THE FREAKIN' WATERLINE. It doesn't make sense. The only logical reason those voids are there would have to be something to do with either boat launches at speed or the propulsion system itself. For starters, think how far down the ship would have to be before these voids would come into play.
You can get some sense of how the butt cheeks affect the wake here and here...
If those extensions are for bouyancy..;.What happens when they get holed?
Just an idea, but is it possible that they are not floats, but are weights to adjust the trim?
The bouyancy tank (a/k/a cheeks) will do the reserve bouyancy if she is down in he stern. So that does make some sense. There are likely factors from drag and andwash from the jets that have to do with the shape and height of the cheeks as well what a sea will do when at rest / slow. So that is a fair amount of reserve that must be found by other means, kinda sort makes you wonder what gets deleted.
One does hope that her name on the stern, flanked by a cheek on the left and a cheek on the right does not get called a Tramp Stamp.
Read the links folks, it's as leesea said. The quote from the Gold Crew CO "to give the ship additional buoyancy, if, for some reason, we were lower in the water."
Translation, all of the overweight issues that have been discussed ad nauseum adversely affected damaged stability calculations and she didn't have enough reserve buoyancy, this is the unglamorous solution. They are not weight, though I do hope mission equipment will help the bow down trim I saw about a year ago.
RE Boat ops, unless they dramatically affect centerline wake it won't be an issue, the doors have to open out anyhow, the bustles are outside the doors.
If they get holed the issue will be where they get holed, any number of permutations there, worst case scenario they're full of water, then you're just dealing with the added weight of the metal which is pretty insignificant. If these things are submerged I'd be far more concerned about free surface and downflooding issues from that side door.
RCS, 90 deg corners are BAD. There are too many RCS issues with LCS to even begin worrying about here.
Kluge.
In an interesting coincidence, the first advertisement on this page was for "Elephant Dung Collector".
Nice.
-RH
Nope. You don't put bouyancy tanks above the waterline, especially all the way at the very end of the ship.
What you people seem to be forgetting, is that these things are made here in Wisconsin. We Badgers always like to add weight in the rear end of our vehicles, to give better traction in the snow. It IS February, you know. I am sure one spring gets here, off they will come, along with the chains on the pump jets.
Edit before post: it went snarky as many posts regarding LCS do. I don't mean to take a shot at you Byron.
Stop applying logic and common sense to the project. You don't do this in a well designed and well managed project, but like so many Navy projects you know which side of the fence LCS sits.
If they are only for damaged stability and reserve buoyancy issues they make sense, in the twisted way most things in the LCS program make sense.
There is a difference between should and do, they should not have to put them there but they do. They probably shouldn't be deploying an asset that doesn't meet basic requirements but they are. These unsightly additions are classic Navy misapplied band-aid ORM, we recogonize a problem and are going to do what we want anyhow so this stupidity mildly mitigates previous stupidity.
Bryon the label said Bouyancy Tank and the XO confirmed I could read english! LOL
By SEPCOR, I have confirmed the internal tanks are in case of a damaged stability incident and will be removed in LCS-1's PSA. Not quire sure what they are doing differently to LCS-3.
But know for a fact that the design is more than 10% overweight today.
P.S. the after mission decks are very wet when the stern doors are open to launch boats etc. As in the ship is down by the stern too damn much!
Lee, I can have a label plate made to say pretty much anything. Point of fact, no where on any navy ship have I ever seen a tank labeled "Bouyancy Tank". This one would be 1-305-2-V (for Void) and -1 for starboard. Second, the XO knows what the LM design guys tell him the tank is. I will repeat, a bouyancy tank ABOVE the waterline is about as useless as teats on a boar hog. Also, if the mission decks are too wet when the stern door is open then the tanks would work MUCH better if they were UNDER the wet deck.
Just think for a second: a void full of air IN the air (as these obviously are) has zero value to raise (what bouyancy does) A void BELOW the waterline, has a + value to raise.
Last, but not least, from day one, the FFGs have never had to have an additional "bouyancy tank" installed. They got built right.
Bingo on the P.S. Even moreso than most realize...
Phib, THANK YOU! This was the best laugh I've had in weeks.
I'm here for 'ya. :-P
When I look at that side view that our Most Noble Sid linked us too, I can't help but think of the saying, "if it looks good, it probably IS good", and say to myself, "the LCS even looks like a mistake". A warship must have good visibility for the helm and the OOD, yet they put those antenna domes right in front of the wheelhouse windows. That crew is gonna get hurt, first time they get near something.
Bryon email me and I tell you the rest of the story of the internal bouyancy tanks.
I just found out that the initials of the ships sponsor, Mrs. Brigit Smith, are welded onto the keel. Is it disrespectful to note that the lead LCS has BS elded right into her main structural member?
Uhh, you're looking in the wrong spot, the antennas are above the bridge. That said there are no shortage of visibility problems from the bridge.
WTH, I think you are saying is that these are "emergency floation tanks." That may make sense if the Freedon does not have enough reserve Bouyancy to meet the Navy's regulation. My guess is to allow that early deployment, they just added these tanks clear that requirment.
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