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>>This is the third refinement of the 5000 ton FFG500 concept<<

The Fletcher class is a 5000 ton guided missile frigate designed to bridge the capability gap between the lightly armed LCS and the Arleigh Burke class destroyers. It was designed in response to the opinion the LCS is not a survivable platform in contested waters and has no value as a carrier escort, while the Flight III Arleigh Burkes are too costly to be built in sufficient numbers to replace the Perry class frigates and too expensive to operate.

With a $1 billion cost cap and an accelerated 4 year development schedule, the FFG 500 program is better defined by what it specifically excludes than what it includes. The program specifically forbids incorporation of any weapon, sensor, electronics or propulsion system that is not already in service. It will not mount any long range volume search radar or have any ballistic missile defense capability. It will not introduce a new sonar system. It will be crew by 100 officers and sailors – roughly 1/3 the Arleigh Burke Class’s complement. And, it will be built using off-the-shelf merchant marine propulsion systems that is already in successful service on more than one class commercial vessel. Within those limitations, it is to have as much firepower and the ability to engage as wide a variety of threats as is practical.

The hull itself is draws from the DDG1000 layout with a small superstructure and plan form aligned low observables geometry. Unlike the Zumwalt however, the Fletchers are not a tumblehome design and features a flared hull for better sea keeping. The hull itself is very slender with a knife edged profile. This allows the ship to have a speed length ratio of 1.52 and attain speeds which allows it to keep up with Carrier Strike Groups when needed.

The ship uses a Zumwalt style Integrated Power System (IPS) with 51.5 MW of total electric generation capacity from a 34.7MWe gas turbine and two 8.4 MWe medium speed diesel generator sets. Of this, up to 42 MW may be committed to the propulsion motors leaving 9.5MW for power hungry shipboard systems and modern sensors. The propulsion design uses a commercially available ABB Azipod XC propulsion system. This combines a static 25MW electric motor driving a 5.2 m 5-bladed propeller with 17MW all azimuth propulsion pod fitted with a 4.2m 7-bladed screw.The contra-rotating single skeg, twin screw design is the most hydro-dynamically efficient arrangement which also permits exceptional maneuverability. In US Navy tradition, the Prairie-Masker air injection system is installed for acoustic suppression. The combined output of 42MW (56,322 shp) is sufficient to drive the ship at up to 31.6 knots. Operating on just the diesel engines with 14MW dedicated to propulsion and 2.8MW available for other uses, the ship is capable of making 20 knots and attain an unrefueled range of 8000 nm. The FFG 500 is also the first navy ship capable of self-docking at practically every location without the aid of harbor tugs.

The sensory suite adopts the existing SPY-3 X-band Multi-Function Radar without the SPY-4 VSR component. A supplementary SPQ-9B Horizon Search radar provides backup navigational and sea skimmer detection when the SPY-3 is tasked with volume search. The bow sonar uses the same SQS-61 high frequency array on the Zumwalt without the larger accompanying SQS-60 medium frequency unit. An SQR-20 Towed Array is carried for extended range underwater detection.

For a 5000 ton ship, the FFG500 is very well armed with 40 Mk57 VLS cells each capable of carrying a quad pack of ESSM Block I or Block II weapons, or a single SM-2, SM-6, LRASM, VLA or Tomahawk Missile. In addition, the FFG500 carries the 24-cell Longbow Hellfire VLS for small craft defense and two 4-cell ExLS VLS modules for launching Chaff and Decoys. The gun armament consists of the LCS’s 57mm Mk110 gun and a single retractable Mk38 mod(2) 25mm cannon. Housing the guns within an enclosed mounting or below decks reduces weathering and required maintenance in addition to reducing the ship’s RCS. For ASW tasks the vessel carries the standard Mk32 324mm torpedo tubes behind amidship doors just ahead of the hangar spaces. A single MH-60R Helicopter is carried along with up to two MQ-8B Firescout UAVs.

Because of the relatively high costs of the ships, it has been suggested that the 30 ship Fletcher class may be reduced to 12 ships with the remaining 18 ships built as a cost/capability reduced type. These being without the SPY-3 radar and just 16 VLS cells. They are to be tasked primarily with ASuW and ASW missions, carrying 16 ESSM Block II missiles for self-defense and 12 VLA or LRASM missiles for their targeted mission. The Hellfire VLS and ExLS launcher is retained for Littoral combat. The Fletcher design is also to be intended for export to Japan, Korea, Taiwan, Israel and Canada -- some as license built hulls -- with the total export numbers equally or exceeding the US Navy adoption rate.

A Derivative of Fletcher Class is the U.S. Coast Guard's MHEC-760 Ross Bell class Maritime High Endurance Cutters. The Ross Bell class shares the same hull and propulsion system with the Fletcher class. However, the Coast Guard vessels do not carry the SPY-3 radar, ASW sonar systems or the Mk57 VLS. Instead it features increased crew berthing spaces and fuel bunkerage for a 12,000 nm cruise range. The Ross Bell class MHEC also features an enlarged Hangar Door and an aviation deck layout sufficient to operate two helicopters simultaneously. The 57mm gun, 25mm cannon, Hellfire Missiles and countermeasure launchers are retained for self-defense. The torpedo tubes are replaced by a pair retractable .50 Cal chain gun mountings. 8 MHEC ships are planned for the U.S. Coast Guard.

First ship to be able to dock without help of tugs. Welcome to the real world. We have done that with a 40 year old frigate here in Norway for many years. And our modern frigate do it to. That someone need help of an tug to get an 130+ vessel in to harbor just show that the person can't handle the ship size, power, the motion and the wind.

Here in Norway we just rescued an cruise ship, where an tug gave it a small push at the stern to turn it correct up to the wind and let the nature push it of ground.... It's called know how to use the environment around you if you can't do that then why are you in the Navy...

And as Jeremy Clarkson said: "It's late, and I'm drunk!"

Dat topweight

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Well... there are many ports which have limited maneuver room. You will not be able to self-dock a ship without harbor tubs unless you have the ability to per form both zero knot turns and zero knot lateral traverses. You cannot do it with a ship that has two traditional propellers. You cannot do it with just a bow thruster. You need the ability to turn your propellers 90 degrees and have a bow thruster. Most cruise ships have such a facility -- most have pods and more than one bow thrusters. Most Navy ships have neither no bow thruster and none that I know of thus far have pods.

There are navy ships with pods, mostly amphibious warfare ships such as the Mistral.

Come to Norway mate, we do that you are talking about with no tugs... there is many tricks you can do but one of the simplest tricks in the world is to get you'r bow toward the dock, then you just have an mooring from the ship down to the dock, all you have to do then is just work on that mooring and push you'r ship in.

Red color is mooring, Brown color is the trust from that ship, blue is the direction a ship move.




Navy ship in Norway:

- Oslo class frigates of the 60's, single screw, single twin ruder (giving bad handling at low speed, but great handling at high speed), turbine power plant (20.000 hp forward trust engine, 4000 hp revers engine). operated during it's carer out of small Naval bases that are so small the the ship had only a few meter to move on, but still manage to get in to dock, even during the famous Norwegian Winter storm. And without Tug's.

- Coast guard vessels, it have literally been a hundred different coast guard vessel in Norway the last 50 years. all without bow or stern trusthers, they all managed to get in to dangerous areas with small area to move on, but still managed to get around... without help of tugs.

- Fridtjof Nansen class frigate. planned during late 90's build 2003-2010.Originally meant to be an ASW frigate, redesigned to an Multi-role frigate all equipped with bow mounted retractable bow trusther (can move 5 knots on them, excellent to use when you are listing after something that are under you).... 133 meter vessel 5200 tons.... no tug help either.


The Azimut come around only to make the work more easy for captains, specially those that doesn't have that skill to get there ship in to harbor on twin screws (twin screws can be used as an side ways trusther, if you can the trick. A real good captain can use a single screw as trushter...). But hey what I have seen of US ship operators... Bow trusthers, stern trusthers, azimut pods, etc. is all there to make something that are easy to do before, just a little more easy. specially for cruise ships with there massive superstructure, a Naval ship with it's large fast responding engine's.... can move around like an small boat!


We had an US Destroyer up in North Norway on a visit, he wanted several tugs to get in to harbor, the "LOS" didn't have time, so he took the entire tug in to harbor an docked it up perfect, without help of any tug. The funny thing was that this "LOS"-man was under training....

(LOS, a Navigator that come onboard the ship in that part of country you visit, with the knowledge of the area)


At the Moment you sound like one that doesn't know a lot about ship.... if you can't dock a ship with now trusther or pods, then you should not work on a ship, so easy is it. (Do you need pods on you'r car to park?)

all in all, one very nice design! interesting choice to place the GT that high in the ship, I might have placed it a bit lower myself (if only to get intake filters and exhaust cooling on board)
I have a small set of comments though.
- the above the water hull looks great! the underwater hull at the bow might require some work though, there are some very sharp angles on top of the sonar bulb. this makes sense to do at a later stage in the design though, but if the ship was actually build that would change.
- the propeller setup makes A LOT! of sense. I have recently seen this setup used at superyachts and I think it is the best solution for pods on warships currently available.
- I might suggest an retractable thruster instead of the bow thruster. bow thrusters have the tendency to disrupt the stream along the sonar bulb, which you have solved with hatches, which have the tendency to get stuck your setup works though.
- the stabilisers stick out a lot outside the hull. may I advice to make them less angled down, shorter, or retractable? if you make them retractable you will need a set of bilge keels to make up for them, but that seems a good idea to me anyways.
- the anchor is a bit far aft, but I personally see no good way to place it forward other then a bow anchor, which might be a problem in such a sharp bow
- the manual watch stations might interfere with the radars in my opinion. but, I see you changed the shape of the aft one to reflect the penetration of the SPY-3, so I do think you already kept that in mind.

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Yes the idea of the ship is good. There are some small things here and there as ace. Mentioned. I would also try to make the superstructure a bot lower to get the center of gravity as low as possible.

The upper most deck placement of the gas turbines is actually a common cruise ship layout. The Celebrity Millennium Class ships for instance has two gas and one steam turbines one the upper most (enclosed) deck. This is possible only on ships which feature electric drives main propulsion. It provides for easy turbine replacements and it eliminates the space wasting intrusions by the air and exhaust ducts. A characteristic of Gas Turbines is that they are actually very light. The turbine plant and its generation combined is only about 97 tons -- about 1/4 the weight of diesel generator sets of a similar output. Putting 97 tons of anything topside is not much of an issue in a 5000 ton vessel. The reason warships do not typically do not do this is that they use their turbines in a direct drive setup which means they have to be in the bowels of the ship near the propeller shaft axis.

Efficiencies aside, the contra-rotating props with a fixed propeller and a pod all along the center-line is a necessity for a warship with a 14m beam -- or any warship up with less than about 24 m of beam width for that matter. This is each of those ABB Azipods are about 11.3 m long. RR Mermaid Pods can be a little shorter, but they put the motor in the hull instead of inside the pods and have a somewhat less stellar reliability record (ie. in the Queen Mary 2). If you have two side-by-side pods you won't be able to turn them sideways with the ship at pier side without them sticking out and hitting something or each other -- unless you have at least 22.6 m of beam plus a little extra width for clearance.

note that upper deck gas turbines actually keep using the large funnel most of the time. also, cruise ship gas turbines do not need to have their infrared signature masked and thus have less exhaust cooling. something I just noticed btw, rain can get into your gas turbine intake. this is one of the main reasons the intakes are often at the sides, never at the top.

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Drawings are credited with J.Scholtens
I ask of you to prove me wrong. Not say I am wrong, but prove it, because then I will have learned something new.
Shipbucket Wiki admin