Cuhail,
If im not mistaken, the boat that you are refering to may be the US Navy MkV ( Mark Five) Special Operations Craft. These are operated by SWCCs ( Special Warfare Combatant craft Crewman. They also operate the Rigid hull inflatables like the one that Frenchy which looks to be a 14ft? one.
Here are some basic demensions of the 3 most common USN SOC, All content from the SWCC Webpage
Mark V Special Operations Craft (MKV SOC) 
General Characteristics
Length Overall: 81' - 2" Beam: 17' - 5 3/4"
Draft: 5' Maximum (static)
Fuel Capacity: 2600 Gallons
Construction: Aluminum Hull
Engines: Twin 2285 HP MTU 12V396 TE94 Diesel
Waterjets: KaMeWa50S
Top Speed: 45-48 Knots
Range: 500+ NM 
11-Meter NSW Rigid Inflatable Boat (11M NSW RIB) 
General Characteristics
Length Overall: 36'
Draft: 2' 11"
Fuel Capacity: 180 Gallons
Construction: FRP w/air-filled sponson
Engines: 470 HP Twin Caterpillar 3126 Diesels
Waterjets: KaMeWa FF280 Mix
Top Speed: 45+ Knots
Range: 200+ NM 
Special Operations Craft Riverine (SOCR) 
General Characteristics
Length Overall: 33'
Draft: 2'
Fuel Capacity: 190 Gallons
Construction: Aluminum Hull w/FRP accessories
Engines: 440 Twin Yanmar 6LY2M-STE Diesels
Waterjets: Hamilton HJ292
Top Speed: 40+ Knots
Range: 195+ NM 
Hope this info helps.
Heres the official SEALS Website. 
http://www.seal.navy.mil/HTH
Matt 
