Tuesday, April 24, 2012

LCS: The Unbearable Sight of Crackl'ns

This pic if one from POGO's letter about LCS that was bouncing around twitter yesterday. 

When someone mentions problems with cracks in a ship, I look over to the corner of the front porch toward the sound of crunching pork rinds and the smell of Vienna Sausages to the ready yardbird. 

Byron? Thoughts?
Cracks in the port and starboard forward corners of the deckhouse right about the bi-metallic and steel coming (same arrangement as found on FFG and CG) is telling us that the entire front of the house is wobbling from side to side. More or less, the aluminum is being compressed down, then stretched up. Eventually metal fatigue will have it's way and you'll have cracks there. Navy will try to fix this by establishing "critical weld procedures" for certain areas where cracks show up (from bad design and lack of stress analysis) and by inserting thicker plates in these locations. As you can guess, the problem hasn't gone away; the cracks will move above, inboard or aft of the thicker plate. It's the same system they've used on FFGs and CGs when they don't want to admit they had faulty design. BTW, the black material you see where the arrows say, "Crack" is polysulphide, something the Navy uses a lot like old body men used to use on rusty cars to fill holes; high dollar "bondo". Lately we seem to use it a lot. Matter of fact, we sent USS Spruance to her fate during the decom with about a gallon of it on top of a holed fuel tank. ISYN. Also, the choice of material comes into play here: 6061 aluminum is used on these vessels. Unlike 5456 (as used on the existing aluminum ships), 6061 is "stiff"; it does not react well to bending forces, i.e, it will crack before it bends. ... the Navy is already blaming poor welding for the cracks, just like they did on FFG and CG. No offense, but the crack in the forward corners of the deckhouse were NOT in the welds, but above them! Stupid ass-covering bastards, they’re going to seriously add costs to the lifecycle of these ships. Worst of all, these started in the first year of the ships life! FFGs had the decency to wait a few years more. Then again, they weren’t built of that crappy 6061 aluminum, either.
Finally - everyone should look over this additional goodie from our friends at POGO. No, those aren't new Klingon Warbird designs ... those are limiting speed-heading profiles.

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