I know little of naval matters (as someone is bound to point out), but as a layman two things puzzle me. The first is the lack of gun armament on modern western warships. Even the otherwise well armed Israeli frigate mentioned in the G2mil pages is offered with either a 76mm gun or a 20mm CIWS. Surely that is a big boat to be protected by just one CIWS turret? The other thing is the lack of smaller craft. There are just some things that a frigate is too big for. Some navies do have small torpedo or missile boats, but these are often limited in the systems that they can mount. I suggest an intermediate vessel, which I'll term the Pocket Corvette.
The main feature of the Pocket Corvette is its armament. Moving from bow to stern, a typical vessel (Fig A) mounts:-
A gun turret mounting dual-purpose guns either a 76mm OTO (known in the USN as the Mk75) or a twin 57mm. This turret may alternately mount a 2x5 barrel 40mm Heavy CIWS. These barrels are possibly fed from a single chamber. In addition to more range the larger calibre also allows features such as proximity fuses or projectile guidance.
A 20mm or 25mm CIWS system mounted over the steering house for maximum field of fire. This can also be used to fire on surface targets.
Behind the mast are vertical launch bins for a anti-aircraft/anti-missile system such as Seawolf. Software allows these to also be directed against targets either on the water surface or on the shore.
Amidships is a cluster of launch tubes (at least eight). Each tube can contain either a Harpoon SSM, a long-range SAM (such as RIM-67 Standard, compatible with Harpoon launchers) or an ASROC - a rocket with a torpedo as second stage. These tubes might also be replaced with tubes containing multiple or single shore bombardment rockets.
Beyond the launch tubes is another CIWS position and another 76mm gun turret.
The vessel may also mount Helicopter RPVs as "flying crow's nests". These may also be used as a flying Boson's chair to transport men or materials between vessels. Smoke generators, heavy machine guns and possibly depth charges and conventional torpedo tubes may also be carried.
What superstructure there is is sloped for protection and shaped for good stealth characteristics. The external decks are more like trenches and gun pits, which offers protection from snipers on the shore. As much of the ship as possible is enclosed for NBC/weather protection. An external shower system can be used to wash fall-out from the exterior or to fight fires.
This basic configuration can be used for conventional hulls, but is also applicable to Surface Effect ships, Catamarans and Hydrofoils.
Pocket Corvettes have numerous roles. The above design serves as an antiaircraft vessel, ASW, missile or torpedo attack boat or gunboat; depending on how the container launchers are loaded. An obvious use is as an inshore patrol vessel. In a fleet role PCs can be used to form part of the defensive screen against aircraft, subs and surface vessels. In this role you'd need some form of mother-ship for supply -I see this as a sort of cross between a freighter and a corvette or frigate. This will mount the same weapon systems as the PCs. Certain naval men have been pointing out the better sea worthiness of a short broad hull over a long narrow one and this might lend itself well to being a PC tender, as might a SES based ship. PCs can also be supplied by supply ekranoplans or cargo submarines.
Like many current warships, the Pocket Corvette uses a modular weapons system. This gives several options:-
A major role may be coastal patrol and protection of offshore assets. In this role some of the armament can be replaced by more crew, cargo or rescue equipment. The Cutter version (Fig B) may just mount one gun turret, one CIWS and maybe Seawolf, or possibly just CISW and machineguns. The version I've shown also mounts a landing pad for helicopters. Because the construction is modular a Cutter can be easily converted to a Corvette if needed.
"C" shows a vessel reconfigured for a fire support role in amphibious landings. A long-range T6 155mm gun turret is mounted amidships and the bow gun turret has been replaced with a launcher for E-FOG missiles or a battery of smoke screening rockets. These weapons are used for both direct fire against targets on the beach and indirect fire in support of forces further in shore. Another specialized shore support variant mounts a MBRL system with a large number of reloads. This is used to lay down a large scale smoke screen and maintain it with a slow sustained fire. Some warheads will also contain jamming devices. Carlton Meyer has suggested that such vessels might also mount M1 tank turrets. Turrets equipped with M119 105mm guns are also possible.
Another variant of the Pocket Corvette is a small submarine with the same armament and also pre-loaded torpedo tubes. This "GunSub" travels to the operations area submerged at the depth where pressure negates turbulence for optimum speed. The GunSub usually fights on the surface, using its full range of weapons and sensors. It is not so much a submarine as a shore bombardment vessel that can creep up on its objective. A few such vessels in each fleet would be useful support and insertion systems for Special Forces operations in the littoral zone. They might also be used as the first wave of an amphibious assault.
Update When I first wrote about the Pocket Corvette one of my main goals was to suggest a vessel more capable than the various small patrol boats. I chose to call this vessel a Pocket Corvette since it would be smaller than a Frigate. Wikipedia defines a modern corvette as a warship of between 55 and 100m length and I visualize this vessel as being between 45 and 70m with around 50m length being most likely so the name is fairly good description. Exact length will of course depend on the hull type selected. Surface Effect Vessels and SWATH ships tend to be wide for their length so can fit more systems onto a shorter hull.
A larger hull meant that it could mount a more useful and versatile range of armament and sensors. Such a vessel would be useful in full wartime operations but also be economic for less bellicose tasks such as fisheries protection, maritime patrol, anti-smuggling etc. While such a vessel has better endurance and sea-going capabilities than smaller boats it is probably likely that its role will tend to be more defensive than expeditionary.
By using a modular construction the equipment could be varied to suit its current role. In Fig A above I illustrate a weapons fit well suited to Anti-submarine warfare, Air Defence and Anti-shipping missions. In Fig B some of the weapon systems have been replaced by modules that would increase the crew comfort and the endurance of the ship during extended patrols. Some governments have concerns about their territory being infiltrated by midget submarines or other special forces or spy delivery systems and patrol vessels would doubtless mount appropriate sensor systems and weapons such as RBU-1000. Pocket Corvettes could also be configured to serve as mine layers or mine countermeasure vessels or serve as oceanographic survey or intelligence, surveillance and reconnaissance platforms.
One addition I would make to the propose for the suggested layout above is the inclusion of a ramp at the stern that can launch a smaller boat. This modification has been made on some of the USN's Cyclone-class vessels and will prove they useful for many of the proposed missions above