CMN Combattante SWAO 53

Artist's impression of CMN (Constructions Mecaniques de Normandie) Combattante SWAO 53 concept to be unveiled at Euronaval 2012.

The Combattante SWAO 53 is revolutionary stealth ship concept by CMN with a unique outrigger hull design, fitted with a large [helipad] capable of accommodating both helicopters and UAVs. SWAO stands for "Small waterplane area outrigger".

Technical Data
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Design
Outrigger hull design
Missions
N/A
Weapons

Guns:
» 1x 57mm main gun
» 2x 30mm remote weapon stations
Missiles:
» 8x VLS tubes for SAM (likely MBDA's Mica VL)
Sensors, Electronics and Decoys
Sensors are all grouped in a single "C-MAST" integrated mast.
Developed in a partnership between CMN, Cassidian and Ineo Defense, C-MAST is a single compact and lightweight mast, which houses 2D, 3D and navigation radars, optronic, electronic warfare and communications systems.
2x Decoy Launchers
Engines/Propulsion
n/a


Type
Concept Ship
Crew
26 sailors. Accomodation for 9 passengers
Operators
None. (Ongoing project)
Performance
Speed: 30 kts
Range: n/a
Endurance: n/a

Displacement
n/a
Propulsion
n/a
Aircraft
Large platform to accomodate UAVs and Helicopters
Dimensions
Length: 53 m
Bream: 16 m
Maximum Draft: 2.6 m


Source:
http://www.navyrecognition.com/index.php?option=com_content&task=view&id=660

Artist's impression of CMN (Constructions Mecaniques de Normandie) Combattante SWAO 53 concept to be unveiled at Euronaval 2012.

Source:
http://vietsn.com/forum/showthread.php?p=1818793

What is the advantage of the Proa layout for a warship???

I'm not convinced it's really a good design. To a certain degree, these designs are just meant to be different, to draw attention to the company and be an interesting side project for the engineers.

That said, the logic I can see is that you get much more deck area -- enough for a mid-sized helo pad -- on roughly a patrol combatant's displacement, and hopefully enough reduction in roll and pitch rates to make it usable. Compared to a trimaran, another popular approach to increased deck area, the single sidehull offers more easily usable volume (trimarans tend to have very small sidehulls, which can get rather cramped) and possibly less structural weight penalty. There may also be benefits to offsetting the helo pad from the main superstructure (less turbulence, possibly, and maybe even a straight-ahead launch option for winged UAVs).

Wouldn't the SWATH pod style outrigger shown here be equally applicable to a trimaran configuration though, including the usable volume? Because of the thin waterline, the sidehulls below the waterline are submarine pods, thus are essentially inaccessible/unusable except for fixed items like fuel and maybe electric propulsion?

They could be, though the increased wetted area of the SWATH bulbs would wipe out the drag reduction from the classic trimaran layout.

I think the Northrop LCS design used something similar -- a central hull and four submerged lifting bodies as outriggers.

It's not hard to imagine something like this acting as the basic for catapult-launched UCAVs with, as has been mentioned, a straight flight deck. Using traditional aircraft carrier cable arrest technologies and a small catapult, your little armed UAVs would be able to carry a lot more ordance than if they had to deal with vertical take-off or landing.

The ships speed is 30 kts so theres at least potential for something like a small bush plane with a radar could complement the light helicopter and UAVs. It would land and takeoff almost vertically relative to the ship. Of course that gets into the thorny issue of where to cram the additional airgroup on such a tiny hull.

Given the hangarage issue, I think small UAVs are the way to go. And you're right that the relatively high ship speed plus wind can make for a very high wind on deck and could be quite suitable for aircraft with low landing speeds. It's been considered before, but rarely done. I copied and pasted my own comments below from an earlier thread on very small aircraft carriers.

The Miles M.38 Messenger was a STOL light aircraft originally designed as an Airborne Observation Post for artillery spotting and eventually used as a VIP transport and liaison plane. When the U-Boats seemed to be winning the battle of the Atlantic, the folks at Miles figured that a light aircraft launched from a platform on a merchant ship might help. The M.38A Mariner could be loaded with a couple of depth charges and launched with almost no take-off run with just two little solid-fuel rockets. A pair could maintain an unbroken patrol to keep the subs at bay at least during daylight. After a patrol, unused depth charges were dropped in the sea and the aircraft landed with a simple arresting hook and cables, with a bungee-sprung net if it missed the hook. Testing showed that it all worked fine from a 60 ft x 60 ft deck and Miles even flew a plane into the net (with a hole in the middle for the prop, the net just caught the wings) in midair without damage. The scheme was never used, but that was politics.

Click to expand...

Brickmuppet said:

The ships speed is 30 kts so theres at least potential for something like a small bush plane with a radar could complement the light helicopter and UAVs. It would land and takeoff almost vertically relative to the ship. Of course that gets into the thorny issue of where to cram the additional airgroup on such a tiny hull.

Click to expand...

Model of CMN Combattante SWAO 53 on display at Euronaval 2012.

Source:
http://www.militaryphotos.net/forums/showthread.php?219174-Euronaval-2012/page2

Model of CMN Combattante SWAO 53 on display at Euronaval 2012.

Source:
http://www.navyrecognition.com/index.php/home/naval-exhibitions-pictures/euronaval-2012.html?AG_MK=0&AG_form_paginInitPages_653=1&AG_form_albumInitFolders_653=west_europe/france/exhibition/euronaval_2012/pictures/Scale%20models&AG_form_scrollTop=966&AG_form_scrollLeft=0&AG_MK=0

Found the SWAO 53 patent here: Vessel with two floats, such as an assymetric catamaran

Partial translation:

Naval architects are forced to choose between sea-keeping and high performance, each with associated restrictions. Catamarans have high initial transversal stability and a short roll period, causing them to be uncomfortable in heavy seas. SWATH hulls enable a reduction in metacentric height at low angles of heel, improving comfort, but are not suited to speeds above 20-25 knots due to their high wetted surface area. In addition, they are sensitive to load changes and shifts in center of gravity, which limits their payload capability and essentially restricts their military applications to coastal patrol missions.

This vessel combines the strengths of both monohulls and catamarans. It is fast, with the comfort and stability of a monohull in pitch and roll, and the safety of a catamaran at high angles of heel. Its payload and center of gravity allowances are improved compared to a SWATH. Finally, its beam enables it to operate aviation assets.

The main hull supports most of the vessel’s displacement (80%), thereby limiting the outrigger’s surface area. Combined with a high finesse ratio (Length / Cubic root of Displacement = 7-8), this enables high speeds and good endurance. At low angles of heel (<5 deg), the outrigger’s low inertia reduces the righting moment GZ to levels similar to a monohull or SWATH hull. Beyond this angle of heel the righting moment increases rapidly, particularly when the vessel heels towards the outrigger side, as the outrigger digs into the water. When the vessel heels towards the main hull side, the stability curve reaches a more modest peak, with the outrigger acting as a counterweight. This provides high stability and safety.

hole in the ground said:

What is the advantage of the Proa layout for a warship???

Click to expand...

So in summary the key benefits of the proa layout seem to be:

• vs. Monohulls: High length-to-beam, enabling high speed (L/B = 9.6), good righting moment, plenty of topside volume for aviation capability
• vs. Catamarans: Smoother seakeeping (less steep righting curve), wider main hull facilitates internal arrangements
• vs. SWATH: Higher speed (SWATH outrigger represents only 20% of displacement), less sensitive to payload changes
• vs. Trimarans: Lower cost, easier internal arrangements (only 1 outrigger)