APS Pirate Hunting Ship Available

[Ben]

If we can snag it before it goes to the scrap pile...

http://www.foxnews.com/politics/2011/06/18/navys-first-stealth-ship-to-be-scrapped/

[Physics]

Ben Rich is rolling in his grave right now.

[Jim147]

I'm sure they wouldn't find us as a viable group. You'd think we were a motley crew or something.

jim

[Gowen]

Looking at the wiki on stealth ships, not just the Sea Shadow, those ships have very little external walking decks.  The bow is almost completely covered by stealth covering, almost like the front of a sub.  The Sea Shadow is unarmed, we would have to mount our own weapons.

http://en.wikipedia.org/wiki/Sea_Shadow_%28IX-529%29

[Ben]

Looking at the wiki on stealth ships, not just the Sea Shadow, those ships have very little external walking decks.  The bow is almost completely covered by stealth covering, almost like the front of a sub.  The Sea Shadow is unarmed, we would have to mount our own weapons.

http://en.wikipedia.org/wiki/Sea_Shadow_%28IX-529%29

Eh, I was thinking of it more as the recon part of our anti-pirate fleet. Why limit ourselves to just one vessel? 

[Gowen]

Eh, I was thinking of it more as the recon part of our anti-pirate fleet. Why limit ourselves to just one vessel? 

Well... ok.  We can re-flag her right along side the Ark Royal.  I think we should rename one of them the APSS Oleg.

[TechMan]

Can I navigate?

[Hawkmoon]

Maximum speed is a mind-blowing 14 knots, and it's good for operation in conditions up to a 21-knot wind -- which in layman's terms is a "light breeze."

I think we need something older and more, well ... SHIP-like. Something like a destroyer escort.

[Ben]

Maximum speed is a mind-blowing 14 knots, and it's good for operation in conditions up to a 21-knot wind -- which in layman's terms is a "light breeze."

I didn't catch that. It's amazingly slow. A ship like that should cruise at 30 knots easy. I take back my recommendation.

[TechMan]

I didn't catch that. It's amazingly slow. A ship like that should cruise at 30 knots easy. I take back my recommendation.

Well I am glad that the APS Pirate Hunting Committee didn't waste its money on that one.  Gosh Ben, do some more research next time, before getting our hopes up.       

[seeker_two]

As long as we bring Michelle Yeoh with us, I'm in.... 


http://www.bondmovies.net/girls/michelle-yeoh1.jpg

http://www.imdb.com/title/tt0120347/

[Bogie]

I say we use a large container ship. Each container on the perimeter will be outfitted as luxury viewing boxes, and outfitted with composite armor. Passengers will supply their own weaponry, or can rent it. If not enough passengers show up armed, they will be required to pay APS members for their security.
 
If I can make a golf ball mortar, I by golly can make cannons...

[erictank]

Maximum speed is a mind-blowing 14 knots, and it's good for operation in conditions up to a 21-knot wind -- which in layman's terms is a "light breeze."

I think we need something older and more, well ... SHIP-like. Something like a destroyer escort.

The wiki gives 2x that speed (though wikis can be changed by anyone...), and cites high stability in sea-state 6, which it goes on to say is up to 18' waves.

Looking at different sources - wiki, Fox News article, and Federation of American Scientists, I'm finding 3 different spec sets.  Bit difficult to figure out what it can actually do when nobody ELSE seems to be able to say what it can do...  But I've never seen video of it moving at anything but a crawl, so maybe we need something just a little bit faster.

[birdman]

Swath ships tend to have extremely efficient hull speeds due to low waterline (wake) drag...think a crew shell shaped keels, and very low drag pontoons underneath.  Since most of the drag is surface drag, I bet that thing goes quite a bit faster than people think.  But random trivia question...based solely on open source info and math, what is the fastest class of ship in the navy? (note, the Pegasus has been retired)

[Tallpine]

Ok, so what's the point of "stealth" when hunting pirates 

Don't you want to be rather obvious and get the scoundrels to attack you...?

I vote for a yacht with bikini clad girls sunbathing on the deck 

[kgbsquirrel]

If we are also counting non-commissioned ships leased by the US Navy, but only those that actually meet the definition of "ship" and not also boats, then HSV-2 Swift.

[birdman]

If we are also counting non-commissioned ships leased by the US Navy, but only those that actually meet the definition of "ship" and not also boats, then HSV-2 Swift.

Hsv-2 is 45kt max.

Usually, the general rule of thumb is hull speed is 1.34 x (WLL in ft)^0.5. And it takes 2hp/ton to hit this, with speed increasing with the 1/3 power of power/weight after that.  Based on those calcs, a nimitz (280khp, ~95kton) should be able to break 45kts...and 50kts is within the margin of error on the calcs...it's all about waterline length.  Carriers can easily outrun their escorts.

[kgbsquirrel]

Did you bother to take into account the draft, displaced tonnage, drag friction, total presented frontal area, etc.? As a general rule of thumb, general rules of thumb do not necessarily apply in practical real world tests, especially when comparing two entirely different hull designs. But what would I know about this sort of thing? After all, it's not like I used to drive a ship for the Navy or something. 


HSV-2 Swift
Full Displacement: 1,668 Long Tons
Draft: 11.15'
Beam: 88.6' (Catamaran Hull)


Nimitz-class
Full Displacement: 104,600 Long Tons
Draft: 37'
Beam: 134' (Mono Hull)

[dogmush]

I've been on the TSV-1.  I know for a fact a CVN can outrun it.

[kgbsquirrel]

I've been on the TSV-1.  I know for a fact a CVN can outrun it.

Were you manning the Lee Helm?

[Gowen]

Ok, so what's the point of "stealth" when hunting pirates 

Don't you want to be rather obvious and get the scoundrels to attack you...?

I vote for a yacht with bikini clad girls sunbathing on the deck 

You send out a decoy ship and sneak up on them and open fire.

[birdman]

Did you bother to take into account the draft, displaced tonnage, drag friction, total presented frontal area, etc.? As a general rule of thumb, general rules of thumb do not necessarily apply in practical real world tests, especially when comparing two entirely different hull designs. But what would I know about this sort of thing? After all, it's not like I used to drive a ship for the Navy or something. 


HSV-2 Swift
Full Displacement: 1,668 Long Tons
Draft: 11.15'
Beam: 88.6' (Catamaran Hull)


Nimitz-class
Full Displacement: 104,600 Long Tons
Draft: 37'
Beam: 134' (Mono Hull)

I was generalizing to keep within the "open source and math" limit.  While the wave piercing swath design of the hsv is at it's most efficient at speeds above the conventional hull speed (which is why I didn't use the general formula for it), for the conventional hull design of a carrier, in my experience, the general formulas tend to be accurate within 5-10%, with larger ships trending to "better" than the formula would indicate.  I've checked results against quite a few hulls, and it's pretty good.  Now, while I can't say what the actual top speed of a carrier is (that's rather well protected), based on it's open source hull shape, power output, and dimensions, >45 seems rather reasonable.  As a note, the hsv achieves nearly 2x it's "conventional" hull speed, which is why I didn't use the formula for it (and wouldn't for that type of hull)

There are other factors as well, propulsive efficiency being one (the larger/slower the prop, the more efficient), which is also why the big wheels on transport and carrier size ships can absorb so much power (70khp+ per shaft) without losing efficiency.

What kind of ships did you drive? 

[lee n. field]

I didn't catch that. It's amazingly slow. A ship like that should cruise at 30 knots easy. I take back my recommendation.

Hmm. Yeah.  I looked at the picture and thought ekranoplan.

[kgbsquirrel]

Wasp-class (slower than I would have like but very nimble for a flat bottom of her tonnage. I could, and did, turn her 180 inside of 2 ship lengths), various small boats, RHIB's, LCPL's, and was involved in the shipboard handling of a couple class of landing craft, LCU and LCAC. As for open source, I can give you one anecdotal account from a friend who was actually manning the Helm on the USS Kenedy at the time and engaged in a race with the HSV-1X, "we were at flank speed and it blew past us like we were standing still."

Edit: Forgot to mention this, you've noted the "opensource" speed for these catamaran ships, but you haven't noted that their top speed, like the carrier, may not exactly be what is admitted to. The numbers I always heard kicked around amongst my fellow knuckle draggers were in the upper 50's. Salt grainage, variable mileage, etc.

[birdman]

Wasp-class (slower than I would have like but very nimble for a flat bottom of her tonnage. I could, and did, turn her 180 inside of 2 ship lengths), various small boats, RHIB's, LCPL's, and was involved in the shipboard handling of a couple class of landing craft, LCU and LCAC. As for open source, I can give you one anecdotal account from a friend who was actually manning the Helm on the USS Kenedy at the time and engaged in a race with the HSV-1X, "we were at flank speed and it blew past us like we were standing still."

Hmm...well, the cvn's do have slightly more power, a longer hull, and a more efficient planform (especially the newer ones) compared to the CV's, so I still would venture it would be close for equal conditions (combat load, etc)...the HSV's do slow a bit when loaded compared to when light, while the carriers are rarely not at military loadings. 

How about we settle on "it depends", if we both agree that both are capable (based on open source) of speeds of 45kts? 

The wasp class is a good group of ships, (thread digression), what did you like/dislike about them? (I do consulting from time to time for the navy on advanced concepts and am always looking for info from those who served on various ships)