Replacing the Jianghus and sub-chasers?

Just my umprofessional 2 cents.

I figure, while catamarans are good and fast littoral crafts, and is a very stable platforms on relatively calm sea states.. up to state 3, I presumed.

But the truth is, It is also a light platform, which logically cannot take on heavy equipments. And as, Crobato stated - 'super large catamarans lacks of facilities in the world to berth or port them', which is quite true, but how do you explain the 98m HSV2 Swift. Then I assumed you mean a catamaran destroyer class platform, but this kind of platform will be too lightly armoured and would have very poor damage control... because they will likely be built mostly entirely of Aluminium (or light composites) and I question the endurance... such as viable engine repairs at sea (Since the propulsion are in the pontoons).

Which comes to the next discussion, are catamarans suitable in open seas. My take is no, because I can't imagine such a craft facing off con't 6 to 8 m waves. The mono hulls would usually runs full-steam directly towards the on coming wave to pierce thru at the top. But what would a Catamaran do ? The waves would smack directly onto the underside of the flat area between the two pontons, and would lift the entire craft out of the water. Either capsizing it or suffers a large crew casaulties. Which again, can Catamarans recover from capsizing ? If they cannot ... then effectively countering the waves at side ways.. are unimaginable.

Thanks

Waves are not sharp enough to do what you describe. They move with a rolling motion. Anyway, your argument sounds like if your SUV is too long or wide. the peak of the hill would hit the chassis.

Let me remind you for that for several centuries, catamarans and other multihulled vessels like the proas have been prowing both the Pacific and Indian oceans. Let me also remind you a basic engineering principle. If you distribute your weight over the longest and widest possible area, you reduce your pitching and rolling motion to the greatest extent.

I've mapped out a main mast and base for a rear mast, added a DUBV-43 (ESS-1) towed sonar under the helipad (would be upgraded?) and changed the waterjets to twin conventional variable pitch props:


Are my engine rooms (green) big enough and how/where can diesels be vented etc. I want to incorporate IR and underwater noise reduction methods so please advise how these design aspects can be incorporated.

Planeman Have ya' ever been on a warship? I have. I served on 5 USN CV's.

Ahemmmm...That hanger overhead is to low. As someone how actually worked on helos I know that those rotors, rotorhead blades, engines and associated equipment need maintance and have to be removed from time to time. Plus all sorts of maintaince is done on top of a helo. Guys need room on the top to perforn these task. You need at least 5+ meters hangar deck height to perform certain maintance.

As for your deck height of 2.5m ..That would be great if this was a cruise ships. But it is not. It is a warship. I hope your sickbay has lots of bandages because sailors are going to be bumping their heads. Why? Because on a warship there are all sorts of ducting, fuel pipes, overboard discharge pipes, airconditioning ducts, electrical wiring harneses..etc..etc...hanging from the overhead(ceiling).You need at least another meter in height between your decks in my opinion.

The magizine for your foward gun should be below the water line. Why? To increase seaworthyness. That ammo is heavy in large quanties. It needs to be lower in the hull to keep keep your ship stable. Also if you take a direct hit on that foward gun....KABOOM!! Not onlyis the gun mount toast and because of the short distance between the gun mount and the magazine you are jepordizing your whole bow section to major leauge damage.

popeye, would creating a gun magazine further below deck, below the waterline, and then maybe having a vertical tunnel/passage for the ammo to be fed to the gun work? or would that be a waste of design space?

Planeman, for the noise reduction, how about the Prairie/Masker system.
Simple explanation is: masker emits small air bubbles flowing around the vessels hull. These bubbles create a sound barrier for the soundwaves from inside the hull.
Prairie is similar. Air bubbles are ejected around the screws to decrease the size of the under pressure area causing cavitation.
You gotta look for a better explanation on the net...

IR, not so sure here, but you could try some kind of funnels with the hot air inside, these are surrounded by cool sea water. Finaly they exaust just above the water line.

planeman said:

I want to incorporate IR and underwater noise reduction methods so please advise how these design aspects can be incorporated.

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To reduce IR signature you could use same system like on MEKO A-200. Funnel was eliminated, and instead hot exhaust gases are ducted through a horizontal system. Seawater is injected into the exhaust duct to cool the exhaust fumes, before being expelled just above the waterline. Germans say that they managed to reduce IR signature for 75% using this system.

crobato said:

Waves are not sharp enough to do what you describe. They move with a rolling motion. Anyway, your argument sounds like if your SUV is too long or wide. the peak of the hill would hit the chassis.

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They don't need to be sharp... I know that waves rolls... but during a storm at the apex of the wave (If wind is strong, current is high ) the bow of any ship would need to slice thru .. and the force of the residing wave would pound on the underside of any vessels. A mono-hull would disperse the water, but a CAT Type-022 would recieve a full force on it's underside.

Let me remind you for that for several centuries, catamarans and other multihulled vessels like the proas have been prowing both the Pacific and Indian oceans.

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yes, but what are their size and weight ? they are small and very light, and there are space between the sailing platform and pontoons to allow water to slpash off. Cat like the type-022 do not.

Let me also remind you a basic engineering principle. If you distribute your weight over the longest and widest possible area, you reduce your pitching and rolling motion to the greatest extent.

Click to expand...

I have been on a fishing trip in the south China sea in rough seas, and I know the waves do pounds and lift the bow of boat up, with wave higher than the boat's hull hitting the cabin area... long gradual rolling wave is only present before a approaching storm, but once in the storm.. hmmm.. it was this experience that tells me if I was in a CAT of the same size of the fishing boat and designed like the HSV2 or 022, I would be swimming in the ocean.

joshuatree said:

popeye, would creating a gun magazine further below deck, below the waterline, and then maybe having a vertical tunnel/passage for the ammo to be fed to the gun work? or would that be a waste of design space?

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Yes that's how they did it in the past. I honestly do not know what sort of mechnism is used in modern navies to pass ammo from below decks. I'm sure it's done.

I was able to chew on this for a bit more, and here are some further thoughts:

1. This ship that you guys have is woefully under defended in air defence. Having only a MANPAD system onboard plus a CIWS means that this ship will have to operate under the umbrella of friendly aircraft.

2. You guys need to further define the role of the ship. Do you guys intend in the design that the ship will be operating under the cover of aircraft? If so, you can ditch the helicopter as there is no need for one while operating under shore-based air support. If you guys are planning that this ship not operate under the cover of shore-based aircraft, you need a more capable air defence system onboard that can take out enemy aircraft at beyond visual range. The ship has to be more of a multi-role platform in this situation and that means the ship has to be larger in any case to fit everything you need onboard (helicopter, air defence missiles, etc).