All photos credit Navy Recognition
Recently found a brochure for Eastern’s OPC reportedly from last year’s Sea, Air, Space Conference. Credit FCNoVA from this discussion group. We have discussed this class before and here, the comments may still be of interest.
Relative to the question does the design meet the “objective” criteria or only the minimums it looks like relatively good news, meeting or exceeding the objectives in terms of endurance, speed, aviation facilities, and accommodations. I presume since this design meets most of the objective criteria, the other two designs will also similarly exceed the minimums. I will provide some of the information provided in the brochure and then provide my comments.
You can read the brochure here: http://www.mnvdet.com/Other/Eastern%20OPC%20Scan.pdf
DIMENSIONS:
Length overall: 328ft
Length between perpendiculars: 297ft
Beam overall: 52ft
Beam waterline: 48.67ft
Depth: 24.5ft
Draft: 16.1ft
Commentary: Compared to the Treasury Class (327 ft) cutters, this is, of course only one foot longer, but the beam and draft are both substantially greater, greater in fact than the beam and draft of the 378s, so we can expect the full load displacement to be considerably greater than the 327s’ approximately 2500 tons, and close to the over 3,000 ton full load displacement of the 378s. Unless the vertical weight distribution is messed up, these are likely to be good riding, very seaworthy ships, a notable improvement on the 270s and 210s.
Accommodations:
126 total
20 commissioned officers
12 CPOs
94 E-6 and below
Also included are a 466 sq ft physical fitness area, a 20 seat training room, and a 48 seat crew’s lounge.
Commentary: Note these are the accommodations, not the expected crew which will be 15 officers, 89 enlisted, and detachments totalling 12 for a total of 116. The Coast Guard is avoiding the mistake made on the Littoral Combat Ship of assuming a small crew, limiting accommodations, and then finding they need a larger crew than the ship was designed for.
Performance:
Range 9,500 nmi @ 14 knots
Sustained speed: 24 knots
Sprint speed: 26 knots.
Commentary: This is an area I was afraid we would see the design compromised. For similar speeds, this range is comparable to the that of the 378s. At speeds above 18 knots, its all diesel power plant will give it greater range than the 378s.
Main Propulsion/Auxiliary Prop and thruster/Electrical:
Main Prop: Two 12,204 HP MAN geared diesels
Ship Service Generators: 4,1044 kW
Auxiliary Prop/thruster: 750 kW, 1005 HP
Commentary: I interpret this to mean four generators of 1044 kW or 4,176kW total. That is a lot of power generation potential. By comparison a 378′s total capacity is 1500 kW, the 270s have 1425 kW. This suggest that the ship will have a hybrid power plant with the generators used for driving electric cruise motors. Running only three generators, one could probably supply routine electrical requirements and the other two could propel the ship. Two generators would supply the equivalent of approximately 2800 HP, this might be enough to drive the ship at 14 knots. Certainly three generators supplying 4200 HP would be more than enough. This will allow the ship to cruise with the Main Diesel Engines shut down.
The combined horsepower of the main diesels, 24,408 HP is more power than the diesel engines of the National Security Cutters which we know provide a high cruising speed, and it is about three and a half times the power of those on the 378s or the 270s.
The thruster is apparently of the drop down trainable type, allowing it to be used as an emergency or loiter propulsion system. The available power is relatively high meaning the ship could probably make seven or eight knots on the thruster alone.
I expect what we will see is two main engine spaces, each with one main diesel and one or two generators. Hopefully the main spaces will be separated by more than a single bulkhead, perhaps by the engineering control room, so that damage at a single point cannot effect both engine rooms. Hopefully also, at least one generator will be outside the two main machinery spaces. If so, these ships will have extraordinary main propulsion redundancy with at least three different spaces and five different systems capable of moving the ship–two MDE, two motors on the main shafts, and the bow thruster.
Construction: Steel Hull with an Aluminum Superstructure. Commentary: No surprise, although I would have liked to see steel superstructure, but it is a reasonable compromise.
Aviation Facilities:
Hangar: H-65/H-60R+UAS/UAV
Flight Deck: 3725 square feet
Commentary: Good news that the hangar will be large enough to accommodate both a Navy MH-60R and a UAS although I am a bit concerned that since the Navy has moved to a larger airframe for their Firescout, there is a chance that the UAS may not include the latest version of what is likely to become a standard system.
Apparently the Flight Deck is at least as large and probably larger than that of the 378s.
Weapons:
57mm Mk110 mod X
Electro-Optic Sensor System
25mm Mk38 mod2
two .50 cal. ROSAM (stabilized mount) plus two .50 cal. in soft mounts
ESM system
Mk53 mod X ASCM decoy system
Commentary: No surprise in what was mentioned. The radar fire control system that was included in previous specifications was not mentioned. This may have been simply an omission, but the Electro-Optic System might also serve as a firecontrol system, although it would be decidedly inferior to a radar system against surface targets in low visibility and against air targets in all situations. Consequently I am a bit concerned that this system has been compromised in the interest of simplifying the design.
The excess generator capacity may make these ships suitable for use of energy intensive weapons that may be developed in the future.
