The boat will be required to transit to and from the Indian Ocean. It will also be required to deploy across the ocean and may go as far as the South China Sea or Western Pacific. A transit range of around 6,000 nautical miles would be enough to get it to and from Diego Garcia. A typical mission range of around 2-3,000 miles should be sufficent.for operations with out replenishment.
30 knts would be nice but we are dealing with an SSK so we have to be realistic. While its not a fleet submarine it would be nice if it could double up as one on occasion. A speed of 18-20 knts would be enough for this. It would also allow for relatively rapid deployment across the ocean.
As it's an SSK designed for open ocean warfare as well as littorals it would be nice to have a sprint speed of around 30knts.
As a ocean going submarine we will require it to have a bigger payload than a standard SSK
We would also require it to have the ability to launch cruise missiles either from Torpedo tubes or VLS. A total weapon load of 18 - 20 Heavy weapons.
As well as being able to operate in the ocean environment it will also be necessary to under take tasks in littorals. Space and capability to embark special forces will be vital.
Under taking Survey work as well as reconnaissance and mine clearing will also be necessary. In future much of this work will be carried out by UUV's so any design would have to take into account the ability to launch and recover UUV's.
To carry out all of these tasks with the necessary abilities set out we are looking at a vessel with a displacment of around 4,000 tonnes
At the end of the day it's all about the price. I would rather have an extra 4 SSN's if they come in at the same price. However we should remember that this would be a very capable vessel. That being said I think we would have to look at a price tag of around £500 million per vessel. Around half the cost of an Astute.
Whats on the market?
The Type 212 represents the pinnacle of German U Boats. It has a discplacment of 1800 tonnes Submerged running speed of 20 knots but a surface speed of just 12 knts. It can sustain a transit of 9,000 miles but only on the surface at only at 8 knts. It has an AIP system based on Hydrogen Fuel Cells making it probably the quietest submarine running at 20 knts in the world. It hs 6 torpedo tubs and can carry 12 Torpedo's. Unit cost is around $300 million per boat.
France and Spain field the Scorpene Submarine. It is slightly larger than the 212 at 2000 tonnes. It has a smaller range of 6000 naticul miles surfaced and can achieve 20 nauts under water using AIP. It carries more weapins than the 212 with 18 instead of 12. It is an export submarine so it has a higher cost of $450 million.
The Russians have a long history of SSK designs. There latest design on the export market is the improved Kilo Class. With a discplacment of 3-4000 tonnes. It can travel at upto 25 knots and carries 18 weapons.
While I am aware there are more submarines on the market these vessels represent the bulk of export orders to foreign navy's. All of these submarines have relatively slow transit speeds limited range and weapons capability for an open ocean submarine. They are in fact really meant for coastal defence.
Many nations that do not have the ability to build SSN's like Australia, India and Brazil have the desire for a submarine with SSN style performance. A large SSK with AIP, long endurance and a bigger weapons load may be able to tap into a knish currently not filled in Submarine exports.
Home Grown Designs
BMT have two submarine designs.
This is a design for an affordable open ocean going submarine. Its a relatively conventional design. It has a submerged maximum speed of 20 knts with a 9,000 mile snorting range. It has a 18 weapon payload and a submerged displacement of 3600 tonnes.
It also has a ten man lock in lock out chamber for special forces. It can launch cruise missiles but only from the torpedo tubes. It Can also launch and recover UUV's
SSGT ( Submarine Submerged Gass Turbine)
|SSGT from BMT|
The Other design from BMT is the SSGT. This is a less conventional design utilising technology that has previously not been tried in other boats. The main driver behind the design is to be able to sustain high transit speeds while submerged. It can sustain a transit speed of 20 knots for a range of 6,000 miles or 13,000 miles at 10 knts. On battery only the vessel can sprint at 30 knts. Its unique design feature is that is uses a gas turbine in the top of the sail. The turbine can be raised out of the water for the 20 knt transit. It also runs on a fuel cell using hydrogen reclaimed from Kerosene. This gives the boat at 25 day endurance at 5 knts on AIP with out surfacing or using the batteries.
It has 6 torpedo tubes and can carry 12 Torpedo's or Cruise Missiles. It also has 8 VLS for cruise missiles. In addition it can carry 4 UUV's on the hull. It has a lock in lock out chamber for 6 men and can hold upto 40 tonnes of stores for special forces.
For a navy use to dealing with SSN's it will be necessary to choose the highest end design. This is also Bradly in line with what Australia requires. The SSGT has by far the best capability. It may also help to plug a gap in the requirements for many smaller navy's looking for blue water capabilities with a diesel boat. While there are no costs outlined by BMT I would imagine we would be looking at the $500 million + range around 1/3 the cost of a Astute.