diff --git a/src/app/components/.AvailableModulesMenu.jsx.swp b/src/app/components/.AvailableModulesMenu.jsx.swp
new file mode 100644
index 00000000..12d3cfc9
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diff --git a/src/app/components/.BattleCentre.jsx.swp b/src/app/components/.BattleCentre.jsx.swp
new file mode 100644
index 00000000..a8be2023
Binary files /dev/null and b/src/app/components/.BattleCentre.jsx.swp differ
diff --git a/src/app/components/BattleCentre.jsx b/src/app/components/BattleCentre.jsx
index 88ce19eb..addfe793 100644
--- a/src/app/components/BattleCentre.jsx
+++ b/src/app/components/BattleCentre.jsx
@@ -1,5 +1,6 @@
 import React from 'react';
 import TranslatedComponent from './TranslatedComponent';
+import Ship from '../shipyard/Ship';
 import { Ships } from 'coriolis-data/dist';
 import Slider from './Slider';
 import Pips from './Pips';
@@ -8,6 +9,7 @@ import Cargo from './Cargo';
 import Movement from './Movement';
 import EngagementRange from './EngagementRange';
 import ShipPicker from './ShipPicker';
+import Shields from './Shields';
 
 /**
  * Battle centre allows you to pit your current build against another ship,
@@ -27,26 +29,29 @@ export default class BattleCentre extends TranslatedComponent {
     super(props);
 
     const { ship } = this.props;
-    const opponent = BattleCentre.DEFAULT_OPPONENT;
 
     this._cargoUpdated = this._cargoUpdated.bind(this);
     this._fuelUpdated = this._fuelUpdated.bind(this);
     this._pipsUpdated = this._pipsUpdated.bind(this);
     this._engagementRangeUpdated = this._engagementRangeUpdated.bind(this);
-    this._targetShipUpdated = this._targetShipUpdated.bind(this);
+    this._opponentUpdated = this._opponentUpdated.bind(this);
 
     this.state = { 
-      // Pips
       sys: 2,
       eng: 2,
       wep: 2,
       fuel: ship.fuelCapacity,
       cargo: ship.cargoCapacity,
       engagementRange: 1500,
-      targetShip: Ships['anaconda']
+      opponent: new Ship('anaconda', Ships['anaconda'].properties, Ships['anaconda'].slots)
     };
   }
 
+  /**
+   * Update state based on property and context changes
+   * @param  {Object} nextProps   Incoming/Next properties
+   * @returns {boolean} true if an update is required
+   */
   componentWillReceiveProps(nextProps) {
     // Rather than try to keep track of what changes our children require we force an update and let them work it out
     this.forceUpdate();
@@ -55,6 +60,9 @@ export default class BattleCentre extends TranslatedComponent {
 
   /**
    * Triggered when pips have been updated
+   * @param {number} sys SYS pips
+   * @param {number} eng ENG pips
+   * @param {number} wep WEP pips
    */
   _pipsUpdated(sys, eng, wep) {
     this.setState({ sys, eng, wep });
@@ -62,6 +70,7 @@ export default class BattleCentre extends TranslatedComponent {
 
   /**
    * Triggered when fuel has been updated
+   * @param {number} fuel the amount of fuel, in T
    */
   _fuelUpdated(fuel) {
     this.setState({ fuel });
@@ -69,6 +78,7 @@ export default class BattleCentre extends TranslatedComponent {
 
   /**
    * Triggered when cargo has been updated
+   * @param {number} cargo the amount of cargo, in T
    */
   _cargoUpdated(cargo) {
     this.setState({ cargo });
@@ -76,6 +86,7 @@ export default class BattleCentre extends TranslatedComponent {
 
   /**
    * Triggered when engagement range has been updated
+   * @param {number} engagementRange the engagement range, in m
    */
   _engagementRangeUpdated(engagementRange) {
     this.setState({ engagementRange });
@@ -83,9 +94,11 @@ export default class BattleCentre extends TranslatedComponent {
 
   /**
    * Triggered when target ship has been updated
+   * @param {object} opponent the opponent's ship
+   * @param {string} opponentBuild the name of the opponent's build
    */
-  _targetShipUpdated(targetShip, targetBuild) {
-    this.setState({ targetShip, targetBuild: targetBuild });
+  _opponentUpdated(opponent, opponentBuild) {
+    this.setState({ opponent, opponentBuild });
   }
 
   /**
@@ -95,13 +108,17 @@ export default class BattleCentre extends TranslatedComponent {
   render() {
     const { language, onWindowResize, sizeRatio, tooltip, termtip } = this.context;
     const { formats, translate, units } = language;
-    const { sys, eng, wep, cargo, fuel, engagementRange } = this.state;
+    const { sys, eng, wep, cargo, fuel, engagementRange, opponent } = this.state;
     const { ship } = this.props;
 
+    // Markers are used to propagate state changes
+    const movementMarker = '' + ship.topSpeed + ':' + ship.pitch + ':' + ship.roll + ':' + ship.yaw;
+    const shieldMarker = '' + ship.shield + ':' + ship.cells + ':' + ship.shieldExplRes + ':' + ship.shieldKinRes + ':' + ship.shieldThermRes;
+
     return (
       <span>
         <h1>{translate('battle centre')}</h1>
-        <ShipPicker onChange={this._targetShipUpdated}/>
+        <ShipPicker onChange={this._opponentUpdated}/>
         <div className='group third'>
           <Pips ship={ship} onChange={this._pipsUpdated}/>
         </div>
@@ -111,7 +128,10 @@ export default class BattleCentre extends TranslatedComponent {
           <EngagementRange ship={ship} onChange={this._engagementRangeUpdated}/>
         </div>
         <div className='group third'>
-          <Movement ship={ship} eng={eng} cargo={cargo} fuel={fuel}/>
+          <Shields marker={shieldMarker} ship={ship} opponent={opponent} sys={sys}/>
+        </div>
+        <div className='group third'>
+          <Movement marker={movementMarker} ship={ship} eng={eng} cargo={cargo} fuel={fuel}/>
         </div>
       </span>
     );
diff --git a/src/app/components/Cargo.jsx b/src/app/components/Cargo.jsx
index 25ec985a..bad1e2cf 100644
--- a/src/app/components/Cargo.jsx
+++ b/src/app/components/Cargo.jsx
@@ -25,7 +25,7 @@ export default class Cargo extends TranslatedComponent {
 
     this.state = {
       cargoCapacity: ship.cargoCapacity,
-      cargoLevel: 1,
+      cargoLevel: 0,
     };
   }
 
diff --git a/src/app/components/EngagementRange.jsx b/src/app/components/EngagementRange.jsx
index c09b56ec..2f624bd0 100644
--- a/src/app/components/EngagementRange.jsx
+++ b/src/app/components/EngagementRange.jsx
@@ -26,7 +26,7 @@ export default class Range extends TranslatedComponent {
     const maxRange = this._calcMaxRange(ship);
 
     this.state = {
-      maxRange: maxRange,
+      maxRange,
       rangeLevel: 1,
     };
   }
@@ -75,7 +75,7 @@ export default class Range extends TranslatedComponent {
 
   /**
    * Update range
-   * @param  {number} range percentage level from 0 to 1
+   * @param  {number} rangeLevel percentage level from 0 to 1
    */
   _rangeChange(rangeLevel) {
     const { maxRange } = this.state;
diff --git a/src/app/components/Movement.jsx b/src/app/components/Movement.jsx
index f61843df..a098ea2e 100644
--- a/src/app/components/Movement.jsx
+++ b/src/app/components/Movement.jsx
@@ -7,6 +7,7 @@ import TranslatedComponent from './TranslatedComponent';
  */
 export default class Movement extends TranslatedComponent {
   static propTypes = {
+    marker: React.PropTypes.string.isRequired,
     ship: React.PropTypes.object.isRequired,
     eng: React.PropTypes.number.isRequired,
     fuel: React.PropTypes.number.isRequired,
@@ -44,7 +45,6 @@ export default class Movement extends TranslatedComponent {
     const { formats, translate, units } = language;
     const { boost } = this.state;
 
-        //<svg style={{ width: '100%', height: '100%', stroke: '#FF8C0D', fill: '#FF8C0D' }} viewBox='0 0 600 600' fillRule="evenodd" clipRule="evenodd">
     return (
       <span id='movement'>
         <svg viewBox='0 0 600 600' fillRule="evenodd" clipRule="evenodd">
@@ -73,13 +73,13 @@ export default class Movement extends TranslatedComponent {
           // Speed
           <text x="500" y="80" strokeWidth='1'>{formats.int(ship.calcSpeed(eng, fuel, cargo, boost))}m/s</text>
           // Pitch
-          <text x="355" y="410" strokeWidth='1'>{formats.f1(ship.calcPitch(eng, fuel, cargo, boost))}°/s</text>
+          <text x="355" y="410" strokeWidth='1'>{formats.int(ship.calcPitch(eng, fuel, cargo, boost))}°/s</text>
           // Roll
-          <text x="450" y="100" strokeWidth='1'>{formats.f1(ship.calcRoll(eng, fuel, cargo, boost))}°/s</text>
+          <text x="450" y="100" strokeWidth='1'>{formats.int(ship.calcRoll(eng, fuel, cargo, boost))}°/s</text>
           // Yaw
-          <text x="160" y="430" strokeWidth='1'>{formats.f1(ship.calcYaw(eng, fuel, cargo, boost))}°/s</text>
+          <text x="160" y="430" strokeWidth='1'>{formats.int(ship.calcYaw(eng, fuel, cargo, boost))}°/s</text>
         </svg>
-        <button className={boost ? 'boost' : 'noboost'} onClick={this._toggleBoost}>Boost</button>
+      { ship.canBoost() ? <button className={boost ? 'boost' : 'noboost'} onClick={this._toggleBoost}>Boost</button> : null }
       </span>);
   }
 }
diff --git a/src/app/components/Pips.jsx b/src/app/components/Pips.jsx
index dfc7c7ce..8d123e82 100644
--- a/src/app/components/Pips.jsx
+++ b/src/app/components/Pips.jsx
@@ -242,6 +242,7 @@ export default class Pips extends TranslatedComponent {
 
   /**
    * Handle a click
+   * @param {string} which  Which item was clicked
    */
   onClick(which) {
     if (which == 'SYS') {
diff --git a/src/app/components/Shields.jsx b/src/app/components/Shields.jsx
new file mode 100644
index 00000000..376f6f88
--- /dev/null
+++ b/src/app/components/Shields.jsx
@@ -0,0 +1,194 @@
+import React from 'react';
+import cn from 'classnames';
+import TranslatedComponent from './TranslatedComponent';
+import * as Calc from '../shipyard/Calculations';
+import { DamageAbsolute, DamageExplosive, DamageKinetic, DamageThermal } from './SvgIcons';
+
+/**
+ * Shields
+ * Effective shield strength (including SCBs)
+ * Time for opponent to down shields
+ *   - need sustained DPS for each type of damage (K/T/E/R)
+ *   - turn in to % of shields removed per second
+ */
+export default class Shields extends TranslatedComponent {
+  static propTypes = {
+    marker: React.PropTypes.string.isRequired,
+    ship: React.PropTypes.object.isRequired,
+    opponent: React.PropTypes.object.isRequired,
+    sys: React.PropTypes.number.isRequired
+  };
+
+  /**
+   * Constructor
+   * @param  {Object} props   React Component properties
+   */
+  constructor(props) {
+    super(props);
+
+    const { shield, absolute, explosive, kinetic, thermal } = this._calcMetrics(props.ship, props.opponent, props.sys);
+    this.state = { shield, absolute, explosive, kinetic, thermal };
+  }
+
+  /**
+   * Update the state if our properties change
+   * @param  {Object} nextProps   Incoming/Next properties
+   * @return {boolean}            Returns true if the component should be rerendered
+   */
+  componentWillReceiveProps(nextProps) {
+    if (this.props.marker != nextProps.marker || this.props.sys != nextProps.sys) {
+      const { shield, absolute, explosive, kinetic, thermal } = this._calcMetrics(nextProps.ship, nextProps.opponent, nextProps.sys);
+      this.setState({ shield, absolute, explosive, kinetic, thermal });
+      return true;
+    }
+  }
+
+  /**
+   * Calculate shield metrics
+   * @param   {Object}  ship       The ship
+   * @param   {Object}  opponent   The opponent ship
+   * @param   {int}     sys        The opponent ship
+   * @returns {Object}             Shield metrics
+   */
+  _calcMetrics(ship, opponent, sys) {
+    const sysResistance = this._calcSysResistance(sys);
+
+    const shieldGenerator = ship.findShieldGenerator();
+
+    // Boosters
+    let boost = 1;
+    let boosterExplDmg = 1;
+    let boosterKinDmg = 1;
+    let boosterThermDmg = 1;
+    for (let slot of ship.hardpoints) {
+      if (slot.enabled && slot.m && slot.m.grp == 'sb') {
+        boost += slot.m.getShieldBoost();
+        boosterExplDmg = boosterExplDmg * (1 - slot.m.getExplosiveResistance());
+        boosterKinDmg = boosterKinDmg * (1 - slot.m.getKineticResistance());
+        boosterThermDmg = boosterThermDmg * (1 - slot.m.getThermalResistance());
+      }
+    }
+
+    // Calculate diminishing returns for boosters
+    boost = Math.min(boost, (1 - Math.pow(Math.E, -0.7 * boost)) * 2.5);
+    // Remove base shield generator strength
+    boost -= 1;
+    boosterExplDmg = boosterExplDmg > 0.7 ? boosterExplDmg : 0.7 - (0.7 - boosterExplDmg) / 2;
+    boosterKinDmg = boosterKinDmg > 0.7 ? boosterExplDmg : 0.7 - (0.7 - boosterKinDmg) / 2;
+    boosterThermDmg = boosterThermDmg > 0.7 ? boosterExplDmg : 0.7 - (0.7 - boosterThermDmg) / 2;
+
+    const generatorStrength = Calc.shieldStrength(ship.hullMass, ship.baseShieldStrength, shieldGenerator, 1);
+    const boostersStrength = generatorStrength * boost;
+    const shield = {
+      generator: generatorStrength,
+      boosters: boostersStrength,
+      total: generatorStrength + boostersStrength
+    };
+
+    // Resistances have three components: the shield generator, the shield boosters and the SYS pips.
+    // We re-cast these as damage percentages
+    const absolute = {
+      generator: 1,
+      boosters: 1,
+      sys: 1 - sysResistance,
+      total: 1 - sysResistance
+    };
+
+    const explosive = {
+      generator: 1 - shieldGenerator.getExplosiveResistance(),
+      boosters: boosterExplDmg,
+      sys: (1 - sysResistance),
+      total: (1 - shieldGenerator.getExplosiveResistance()) * boosterExplDmg * (1 - sysResistance)
+    };
+
+    const kinetic = {
+      generator: 1 - shieldGenerator.getKineticResistance(),
+      boosters: boosterKinDmg,
+      sys: (1 - sysResistance),
+      total: (1 - shieldGenerator.getKineticResistance()) * boosterKinDmg * (1 - sysResistance)
+    };
+
+    const thermal = {
+      generator: 1 - shieldGenerator.getThermalResistance(),
+      boosters: boosterThermDmg,
+      sys: (1 - sysResistance),
+      total: (1 - shieldGenerator.getThermalResistance()) * boosterThermDmg * (1 - sysResistance)
+    };
+
+    return { shield, absolute, explosive, kinetic, thermal };
+  }
+
+  /**
+   * Calculate the resistance provided by SYS pips
+   * @param {integer} sys  the value of the SYS pips
+   * @returns {integer}    the resistance for the given pips
+   */
+  _calcSysResistance(sys) {
+    return Math.pow(sys,0.85) * 0.6 / Math.pow(4,0.85);
+  }
+
+  /**
+   * Render shields
+   * @return {React.Component} contents
+   */
+  render() {
+    const { ship, sys } = this.props;
+    const { language, tooltip, termtip } = this.context;
+    const { formats, translate, units } = language;
+    const { shield, absolute, explosive, kinetic, thermal } = this.state;
+
+    const shieldTooltipDetails = [];
+    shieldTooltipDetails.push(<div key='generator'>{translate('generator') + ' ' + formats.int(shield.generator)}{units.MJ}</div>);
+    shieldTooltipDetails.push(<div key='boosters'>{translate('boosters') + ' ' + formats.int(shield.boosters)}{units.MJ}</div>);
+
+    const absoluteTooltipDetails = [];
+    absoluteTooltipDetails.push(<div key='generator'>{translate('generator') + ' ' + formats.pct1(absolute.generator)}</div>);
+    absoluteTooltipDetails.push(<div key='boosters'>{translate('boosters') + ' ' + formats.pct1(absolute.boosters)}</div>);
+    absoluteTooltipDetails.push(<div key='power distributor'>{translate('power distributor') + ' ' + formats.pct1(absolute.sys)}</div>);
+
+    const explosiveTooltipDetails = [];
+    explosiveTooltipDetails.push(<div key='generator'>{translate('generator') + ' ' + formats.pct1(explosive.generator)}</div>);
+    explosiveTooltipDetails.push(<div key='boosters'>{translate('boosters') + ' ' + formats.pct1(explosive.boosters)}</div>);
+    explosiveTooltipDetails.push(<div key='power distributor'>{translate('power distributor') + ' ' + formats.pct1(explosive.sys)}</div>);
+
+    const kineticTooltipDetails = [];
+    kineticTooltipDetails.push(<div key='generator'>{translate('generator') + ' ' + formats.pct1(kinetic.generator)}</div>);
+    kineticTooltipDetails.push(<div key='boosters'>{translate('boosters') + ' ' + formats.pct1(kinetic.boosters)}</div>);
+    kineticTooltipDetails.push(<div key='power distributor'>{translate('power distributor') + ' ' + formats.pct1(kinetic.sys)}</div>);
+
+    const thermalTooltipDetails = [];
+    thermalTooltipDetails.push(<div key='generator'>{translate('generator') + ' ' + formats.pct1(thermal.generator)}</div>);
+    thermalTooltipDetails.push(<div key='boosters'>{translate('boosters') + ' ' + formats.pct1(thermal.boosters)}</div>);
+    thermalTooltipDetails.push(<div key='power distributor'>{translate('power distributor') + ' ' + formats.pct1(thermal.sys)}</div>);
+
+    return (
+      <span id='shields'>
+        <table>
+          <tbody>
+            <tr>
+              <td colSpan='5' onMouseOver={termtip.bind(null, <div>{shieldTooltipDetails}</div>)} onMouseOut={tooltip.bind(null, null)} className='summary'>{translate('shields')}: {formats.int(shield.total)}{units.MJ}</td>
+            </tr>
+            <tr>
+              <td className='le'>{translate('damage from')}</td>
+              <td className='ri'>
+                <span onMouseOver={termtip.bind(null, 'absolute')} onMouseOut={tooltip.bind(null, null)}><DamageAbsolute /></span>&nbsp;
+                <span onMouseOver={termtip.bind(null, <div>{absoluteTooltipDetails}</div>)} onMouseOut={tooltip.bind(null, null)}>{formats.pct1(absolute.total)}</span>
+              </td>
+              <td className='ri'>
+                <span onMouseOver={termtip.bind(null, 'explosive')} onMouseOut={tooltip.bind(null, null)}><DamageExplosive /></span>&nbsp;
+                <span onMouseOver={termtip.bind(null, <div>{explosiveTooltipDetails}</div>)} onMouseOut={tooltip.bind(null, null)}>{formats.pct1(explosive.total)}</span>
+              </td>
+              <td className='ri'>
+                <span onMouseOver={termtip.bind(null, 'kinetic')} onMouseOut={tooltip.bind(null, null)}><DamageKinetic /></span>&nbsp;
+                <span onMouseOver={termtip.bind(null, <div>{kineticTooltipDetails}</div>)} onMouseOut={tooltip.bind(null, null)}>{formats.pct1(kinetic.total)}</span>
+              </td>
+              <td className='ri'>
+                <span onMouseOver={termtip.bind(null, 'thermal')} onMouseOut={tooltip.bind(null, null)}><DamageThermal /></span>&nbsp;
+                <span onMouseOver={termtip.bind(null, <div>{thermalTooltipDetails}</div>)} onMouseOut={tooltip.bind(null, null)}>{formats.pct1(thermal.total)}</span>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </span>);
+  }
+}
diff --git a/src/app/components/ShipPicker.jsx b/src/app/components/ShipPicker.jsx
index 49b67a2e..9f319a14 100644
--- a/src/app/components/ShipPicker.jsx
+++ b/src/app/components/ShipPicker.jsx
@@ -56,7 +56,8 @@ export default class ShipPicker extends TranslatedComponent {
 
   /**
    * Update ship
-   * @param  {object} ship the ship
+   * @param  {object} shipId  the ship
+   * @param  {string} build   the build, if present
    */
   _shipChange(shipId, build) {
     const ship = new Ship(shipId, Ships[shipId].properties, Ships[shipId].slots);
@@ -71,6 +72,7 @@ export default class ShipPicker extends TranslatedComponent {
 
   /**
    * Render the menu for the picker
+   * @returns {object}    the picker menu
    */
   _renderPickerMenu() {
     const { ship, build } = this.state;
diff --git a/src/app/shipyard/Calculations.js b/src/app/shipyard/Calculations.js
index e5b56dc0..7e74913b 100644
--- a/src/app/shipyard/Calculations.js
+++ b/src/app/shipyard/Calculations.js
@@ -174,6 +174,20 @@ function normValues(minMass, optMass, maxMass, minMul, optMul, maxMul, mass, bas
 	  res];
 }
 
+/**
+ * Calculate a single value
+ * @param {number}   minMass  the minimum mass of the thrusters
+ * @param {number}   optMass  the optimum mass of the thrusters
+ * @param {number}   maxMass  the maximum mass of the thrusters
+ * @param {number}   minMul   the minimum multiplier of the thrusters
+ * @param {number}   optMul   the optimum multiplier of the thrusters
+ * @param {number}   maxMul   the maximum multiplier of the thrusters
+ * @param {number}   mass     the mass of the ship
+ * @param {base}     base     the base value from which to calculate
+ * @param {number}   engpip   the multiplier per pip to engines
+ * @param {number}   eng      the pips to engines
+ * @returns {number}           the resultant value
+ */
 function calcValue(minMass, optMass, maxMass, minMul, optMul, maxMul, mass, base, engpip, eng) {
   const xnorm = Math.min(1, (maxMass - mass) / (maxMass - minMass));
   const exponent = Math.log((optMul - minMul) / (maxMul - minMul)) / Math.log(Math.min(1, (maxMass - optMass) / (maxMass - minMass)));
@@ -184,6 +198,17 @@ function calcValue(minMass, optMass, maxMass, minMul, optMul, maxMul, mass, base
   return res * (1 - (engpip * (4 - eng)));
 }
 
+/**
+ * Calculate speed for a given setup
+ * @param {number}   mass         the mass of the ship
+ * @param {number}   baseSpeed    the base speed of the ship
+ * @param {ojbect}   thrusters    the thrusters of the ship
+ * @param {number}   engpip       the multiplier per pip to engines
+ * @param {number}   eng          the pips to engines
+ * @param {number}   boostFactor  the boost factor for ths ship
+ * @param {boolean}  boost        true if the boost is activated
+ * @returns {number}              the resultant speed
+ */
 export function calcSpeed(mass, baseSpeed, thrusters, engpip, eng, boostFactor, boost) {
   // thrusters might be a module or a template; handle either here
   const minMass = thrusters instanceof Module ? thrusters.getMinMass() : thrusters.minmass;
@@ -201,6 +226,17 @@ export function calcSpeed(mass, baseSpeed, thrusters, engpip, eng, boostFactor,
   return result;
 }
 
+/**
+ * Calculate pitch for a given setup
+ * @param {number}   mass         the mass of the ship
+ * @param {number}   basePitch    the base pitch of the ship
+ * @param {ojbect}   thrusters    the thrusters of the ship
+ * @param {number}   engpip       the multiplier per pip to engines
+ * @param {number}   eng          the pips to engines
+ * @param {number}   boostFactor  the boost factor for ths ship
+ * @param {boolean}  boost        true if the boost is activated
+ * @returns {number}              the resultant pitch
+ */
 export function calcPitch(mass, basePitch, thrusters, engpip, eng, boostFactor, boost) {
   // thrusters might be a module or a template; handle either here
   let minMass = thrusters instanceof Module ? thrusters.getMinMass() : thrusters.minmass;
@@ -218,6 +254,17 @@ export function calcPitch(mass, basePitch, thrusters, engpip, eng, boostFactor,
   return result;
 }
 
+/**
+ * Calculate roll for a given setup
+ * @param {number}   mass         the mass of the ship
+ * @param {number}   baseRoll     the base roll of the ship
+ * @param {ojbect}   thrusters    the thrusters of the ship
+ * @param {number}   engpip       the multiplier per pip to engines
+ * @param {number}   eng          the pips to engines
+ * @param {number}   boostFactor  the boost factor for ths ship
+ * @param {boolean}  boost        true if the boost is activated
+ * @returns {number}              the resultant roll
+ */
 export function calcRoll(mass, baseRoll, thrusters, engpip, eng, boostFactor, boost) {
   // thrusters might be a module or a template; handle either here
   let minMass = thrusters instanceof Module ? thrusters.getMinMass() : thrusters.minmass;
@@ -235,6 +282,17 @@ export function calcRoll(mass, baseRoll, thrusters, engpip, eng, boostFactor, bo
   return result;
 }
 
+/**
+ * Calculate yaw for a given setup
+ * @param {number}   mass         the mass of the ship
+ * @param {number}   baseYaw      the base yaw of the ship
+ * @param {ojbect}   thrusters    the thrusters of the ship
+ * @param {number}   engpip       the multiplier per pip to engines
+ * @param {number}   eng          the pips to engines
+ * @param {number}   boostFactor  the boost factor for ths ship
+ * @param {boolean}  boost        true if the boost is activated
+ * @returns {number}              the resultant yaw
+ */
 export function calcYaw(mass, baseYaw, thrusters, engpip, eng, boostFactor, boost) {
   // thrusters might be a module or a template; handle either here
   let minMass = thrusters instanceof Module ? thrusters.getMinMass() : thrusters.minmass;
diff --git a/src/app/shipyard/Ship.js b/src/app/shipyard/Ship.js
index a9b99652..10da4582 100755
--- a/src/app/shipyard/Ship.js
+++ b/src/app/shipyard/Ship.js
@@ -1286,13 +1286,13 @@ export default class Ship {
       shield = Calc.shieldStrength(this.hullMass, this.baseShieldStrength, sgSlot.m, 1);
       shieldExplRes = 1 - sgSlot.m.getExplosiveResistance();
       shieldExplDRStart = shieldExplRes * 0.7;
-      shieldExplDREnd = shieldExplRes * 0; // Currently don't know where this is
+      shieldExplDREnd = 0;
       shieldKinRes = 1 - sgSlot.m.getKineticResistance();
       shieldKinDRStart = shieldKinRes * 0.7;
-      shieldKinDREnd = shieldKinRes * 0; // Currently don't know where this is
+      shieldKinDREnd = 0;
       shieldThermRes = 1 - sgSlot.m.getThermalResistance();
       shieldThermDRStart = shieldThermRes * 0.7;
-      shieldThermDREnd = shieldThermRes * 0; // Currently don't know where this is
+      shieldThermDREnd = 0;
 
       // Shield from boosters
       for (let slot of this.hardpoints) {