Shields
This article explains the functional process of spaceship shielding. It does not cover the various tactical applications of shields. These can be found in such as:
Shield Tanking Passive Shield Tanking Logistics
Nor does it cover the detailed fitting of shields to specific ships. The descriptions of the various ships include shield fits as appropriate to the hull. (See Hurricane, for example.)
What Is a Shield?
You can think of a shield as a sphere, completely enclosing the ship at a location just inside its Signature Radius. Since the Signature Radius is the effective size of the ship, the area that is targeted by weapons, the shield intercepts any damage that occurs before it can reach the ship.
Each ship has four separate, overlapping spheres, called "resistance layers", each of which protects against a different kind of damage. This means that the ship has a different shield resistance value for each of: thermal, kinetic, EM, and explosive damage.
Resistance indicates how much of that kind of damage will be rejected by the shield when the ship is hit by that kind of weapon. Resistance values are always shown in percentages – for example, "30% Thermal Resistance" means that the shield will reject 30% of the damage from any weapons hit that does thermal damage.
The shield also has a "capacity" which shows how many hitpoints of damage it would take to destroy, or "drop", the shield. In combat this shows as the first of three red rings on the pilot's dashboard display.
A ship's shield also has a "recharge rate" which shows how fast the shield rebuilds itself while damaged.
The base values for all of these can be found in the "Attributes" panel of the ship's Get Info window.
Notice that both ships have the same four shield resistance values. This is because the resistances are expressed in percentages. Because the Hurricane starts out with almost three times as many hitpoints, each percentage absorbs considerably more damage than will the Kestrel.
In each case the shield recharge time is an average of what might happen in practice. The actual shield recharge rate varies quite a bit in combat – this is discussed in the Shield Recharge Rate section, below.
Shield Capacity
Shield capacity indicates how many hitpoints of damage it will take to drop the shields. (The ship itself is also protected by Armor and Hull defenses, and so it will take considerably more than than that to destroy the entire ship.) In general, the larger the ship, the larger the base shield capacity.
Whenever the shield takes damage of any kind, its capacity drops. So while hits that do thermal, kinetic, EM, and/or explosive damage may be mitigated by the shield's resistance layers, any damage that does get through will be subtracted from the Shield Capacity value. This reduction will appear on the pilot's dashboard as a red mark in the outer "shield" ring.
Shield Boosters and Extenders add hitpoints to the capacity of the shield and increases the total amount of damage that the shield can take before it is destroyed. This is an absolute increase in shield strength, and it applies to all damage types.
Shield Recharge Rate
It takes a certain amount of time to recharge a fully depleted shield. This figure is given as the Shield Recharge Time in the ship's Attribute window. Recharging, however, does not tick along like the numbers on a clock. The speed varies depending on the amount of damage the shield has already taken.
In the beginning, the shield charges at its average rate. As the shield takes damage, and it's capacity goes down, the rate it which it rebuilds itself goes up. If you want, you can think of this as the shield storing energy from the hits that it is taking and feeding the stored energy back into itself.
But then, when the shield capacity has dropped to about 25% (in other words, when the shield is three-quarters gone), the recharge rate peaks and begins to fall off. At its peak, the shield will be recharging about twice as fast as it was in the beginning.
At this point a buzzer will sound, to warn the pilot that the shield is at its recharging limit. If it continues to take more damage than it can hold, the recharge rate will drop off quickly, and the capacity of the shield will fall towards zero ... at that point the shield will fail.
This is a simplified version of the Shield Recharge Rate Graph. A ship's shield begins at 100% full capacity ... the left side of the graph. As the shield takes damage, the rate at which it recharges slowly grows, until, when the shield is at about 25% of its capacity, the rate is more than twice what it was at the start.
Flux Coils, Power Relays and Shield Rechargers all increase the Recharge Rate of the shield and so decrease the amount of time it takes to rebuild lost shield capacity. This applies to the absolute strength of the shield; it applies to all damage types.
Both of these modules affect the entire shield; they do not favor one damage type or another.
Shield Damage Type Resistances
There are four types of damage, and a shield will deal with each differently. As illustrated here, a ship begins with a base Damage Resistance value for each type:
Each of these resistances also represents a corresponding "vulnerability" number that shows how much damage will get through the shield for each hit of that kind of weapon. The Vulnerabilities are always 100% minus the resistances. So, for example, a ship with these resistances:
Shield Resistance: EM–0% Thermal–20% Kinetic–40% Explosive–50%
would have these vulnerabilities:
Shield Vulnerability: EM–100% Thermal–80% Kinetic–60% Explosive–50%
This is the damage that would get through if the ship flew with its base shields, with no benefits from skills, modules or rigs. Because of the way the shield enhancement modules and rigs work, it is easier to focus on the shield's Vulnerabilities rather than its Resistances.
Shield Damage Type modules are quite useful because each new module works on the remaining vulnerability from other modules installed earlier. The best way to explain this is to show an example. Suppose a ship's base Kinetic damage resistance is 40%. This means that it's base Kinetic vulnerability is 60%
Now suppose that the pilot installs a module that reduces Kinetic vulnerability by 10%. The reduction amount is 10% of 60%, or 6%. Since this is a reduction, it is subtracted from the original vulnerability to give a new Kinetic vulnerability of 54%.
Now suppose that second module is installed, and that this module reduces Kinetic vulnerability by 20%. This new reduction is applied to the existing Kinetic vulnerability of 54%. So the updated Kinetic vulnerability change is 20% of 54% or 11% (rounded up). The updated Kinetic vulnerability is 54% - 11% or 43%. Here is a summary:
| Base Kinetic Resistance | First Module | Second Module | |
|---|---|---|---|
| Module Bonus | - | 10% | 20% |
| Current Vulnerability | 60% | 60% | 54% |
| Change | none | 6% | 11% |
| Updated Vulnerability | 60 | 54% | 43% |
And of course, if needed, this can easily be converted into a Kinetic Damage Resistance of 57%.
Various modules and rigs have differing benefits and penalties. Among the most important of these are the Stacking Penalties which reduce the effectiveness of a module if other modules of the same general type are already installed. Choosing the proper equipment for a ship comes under the heading of "fitting" which is not covered in any detail in this article.
Shield Hardeners and Resistance Amplifiers reduce the Damage Type Vulnerabilities of the shield.
Since you need a different module for each type of damage, and since most ships do not have enough medium level power slots to handle more than a few modules, it is difficult to use these kinds of modules to protect against all types of damage. One solution is to load the kind of module you need for the expected encounter. Another is to use a "multi-type" module that protects against all damage types.
Using Shields
In some cases the technical construction of the ship dictates the use of Shields (or Armor) as its primary defense. Any ship receiving a bonus to shield capabilites would likely use shields. And because most shield modules use medium level power slots, a ship with more mid than low slots will tend to use shields.
For example, these ships will usually use shields:
- The ORE Procurer, a mining ship, receives a 5% bonus to shield hitpoints.
- The Caldari Moa, a cruiser, receives a 4% bonus to all shield resistances.
- The Caldari Kestrel, a frigate, has four mid slots and only two low slots.
On the other hand, these ships will usually use armor:
- The Amarr Prophecy, a battlecruiser, has seven low slots and four medium slots.
- The Gallente Incursus, a frigate, has a 7.5% bonus to Armor Repairer amount.
It is worth noting that many ships can use either shields or armor. In these cases the choice is a matter of fitting ... what is the goal of the fit, and what are the skills or the pilot.
The argument as to which approach is best never ends. Every type of defense has advantages and disadvantages, and it is always best to fit the ship to match its characteristics, the pilots skills, and the goals of the encounter.
Advantages of Shields
- Do not reduce speed or maneuverability
- As a first line of defense, leaves you with Armor and Hull as a fallback if shields go down
- Recharge on their own – no need to dock for repairs
- Shield recharge modules work more quickly than armor repair modules
- Low slots are available for weapon enhancing modules
Disadvantages of Shields
- Increase signature radius – ship becomes easier to target
- Not possible to fully protect against all damage types
- Fewer kinds of enhancement modules – less choice than with armor
- Shield recharge modules use more capacitor power than armor repair modules
- Mid slots are not available for EWAR, propulsion and scanning modules
Shield Tanking
The term "shield tanking" refers to the use of shields as a ships primary defensive mechanism. There are three general approaches to Shield Tanking:
- Active – use modules that draw on the ship's capacitor to improve shield performance
- Passive – use modules that do not draw on the ship's capacitor; mostly to improve shield recharge rate
- Buffer – use modules that do not draw on the ship's capacitor; mostly to increase the shield's capacity and resistance
This topic is covered in depth in the E-UNI Shield Tanking Course, and in the document on Passive Shield Tanking.
Logistical Shielding
Logistical shielding is the use of one ship's modules to apply shield protection to a different ship. This is covered in the E-UNI courses Logistics 101: Introduction to Logistics and the document Guide to Logistics.
Shield Skills
A variety of skills improve a pilot's use of shields. Some of these are important to all pilots, while others are most important to pilot's who "shield tank" their ships and depend on shields as the primary means of defense.
Basic Shield Skills
These will be useful to any pilot and should be trained as soon as possible at least to Level III.
Shield Management – 5% bonus to shield capacity per skill level
Shield Operation – 5% reduction in shield recharge time per skill level
Shield Upgrades – 5% reduction in shield upgrade powergrid needs
Tactical Shield Manipulation – Reduces the "bleed through" of damage when the shield falls below 25% by 5% per skill level
Shield Tanking Skills
These are of most use to pilots who depend on shields as their primary defense. Refer to the article on Shield Tanking for detailed information.
Shield Compensation – 2% less capacitor need for shield boosters per skill level
[[Skills: Thermic Shield Compensation ]], Kinetic Shield Compensation, Explosive Shield Compensation, EM Shield Compensation – 5% bonus to damage resistance per level for Shield Amplifiers of the type listed
Other Shield Skills
These require advanced training and are of little use to newer players.
Shield Emission Systems – providing shield capacity to other players ... used in Logistics.
Capital Shield Operation – 2% reduction in capacitor need for capital shield boosters per skill level
Capital Shield Emission Systems – 5% reduced capacitor need for capital shield emission system modules per skill level
Technical Section: Shield Recharge Rate
The Average Shield Recharge Rate can be computed by dividing the Shield Capacity by its Recharge Time.
ARR = SC / RT
The Peak Recharge Rate is approximately 2.5 times the Average Recharge Rate. It occurs when the capacity of the shield reaches approximately 25% of its maximum value.
This graph is supplied as part of the EVE University Course, Shield Tanking supporting [material].
There does not seem to be any way to use this information effectively in combat. When the shield is under attack, the changing value of the shield capacity makes it difficult to do a computation, let alone to make use of the results.
