diff --git a/client/src/App.css b/client/src/App.css
index 14a4f21..6144852 100644
--- a/client/src/App.css
+++ b/client/src/App.css
@@ -3311,6 +3311,13 @@ html.theme-cupertino .events-scroll-container {
   font-size: 17px;
 }
 
+.live-log-modal-hint {
+  margin: -8px 0 12px;
+  font-size: 13px;
+  color: var(--app-text-muted);
+  line-height: 1.4;
+}
+
 .live-log-sail-pills {
   margin-bottom: 16px;
 }
diff --git a/client/src/components/LiveLogView.tsx b/client/src/components/LiveLogView.tsx
index 7241fd7..8ab52a1 100644
--- a/client/src/components/LiveLogView.tsx
+++ b/client/src/components/LiveLogView.tsx
@@ -10,6 +10,7 @@ import {
   Droplets,
   FileText,
   Fuel,
+  Gauge,
   MapPin,
   MessageSquare,
   Radio,
@@ -38,6 +39,8 @@ import {
   liveFuelRemark,
   livePrecipRemark,
   liveSailsRemark,
+  liveSogRemark,
+  liveStwRemark,
   liveTempRemark,
   liveWaterRemark
 } from '../utils/liveEventCodes.js'
@@ -63,6 +66,8 @@ type LiveModal =
   | 'course'
   | 'fuel'
   | 'water'
+  | 'sog'
+  | 'stw'
 
 const AUTO_POSITION_INTERVAL_MS = 3 * 60 * 60 * 1000
 const AUTO_POSITION_CHECK_MS = 60_000
@@ -235,6 +240,17 @@ export default function LiveLogView({
     setModal(type)
   }
 
+  const openSogModal = async () => {
+    let prefill = ''
+    try {
+      const pos = await getCurrentPosition()
+      if (pos.speedKn != null) prefill = String(pos.speedKn)
+    } catch {
+      // Manual entry when GPS speed unavailable
+    }
+    openValueModal('sog', prefill)
+  }
+
   const handleMotorToggle = () => {
     hapticPulse()
     void runQuickAction(async () => {
@@ -405,6 +421,28 @@ export default function LiveLogView({
         }, 'live_water')
         break
       }
+      case 'sog': {
+        const speedKn = parseFloat(primary.replace(',', '.'))
+        if (!Number.isFinite(speedKn) || speedKn < 0) return
+        setModal('none')
+        void runQuickAction(async () => {
+          await appendQuickEvent(logbookId, entryId, {
+            remarks: liveSogRemark(String(speedKn))
+          })
+        }, 'live_sog')
+        break
+      }
+      case 'stw': {
+        const speedKn = parseFloat(primary.replace(',', '.'))
+        if (!Number.isFinite(speedKn) || speedKn < 0) return
+        setModal('none')
+        void runQuickAction(async () => {
+          await appendQuickEvent(logbookId, entryId, {
+            remarks: liveStwRemark(String(speedKn))
+          })
+        }, 'live_stw')
+        break
+      }
       default:
         break
     }
@@ -479,6 +517,14 @@ export default function LiveLogView({
             <Compass size={18} />
             {t('logs.live_course_btn')}
           </button>
+          <button type="button" className="live-log-action-btn" onClick={() => void openSogModal()} disabled={busy}>
+            <Gauge size={18} />
+            {t('logs.live_sog_btn')}
+          </button>
+          <button type="button" className="live-log-action-btn" onClick={() => openValueModal('stw')} disabled={busy}>
+            <Gauge size={18} style={{ transform: 'scaleX(-1)' }} />
+            {t('logs.live_stw_btn')}
+          </button>
           <button type="button" className="live-log-action-btn" onClick={() => openValueModal('fuel')} disabled={busy}>
             <Fuel size={18} />
             {t('logs.live_fuel_btn')}
@@ -610,7 +656,7 @@ export default function LiveLogView({
         </div>
       )}
 
-      {['pressure', 'temp', 'precip', 'sea_state', 'course', 'fuel', 'water'].includes(modal) && (
+      {['pressure', 'temp', 'precip', 'sea_state', 'course', 'fuel', 'water', 'sog', 'stw'].includes(modal) && (
         <div className="live-log-modal-backdrop" onClick={() => setModal('none')}>
           <div className="live-log-modal glass" onClick={(e) => e.stopPropagation()}>
             <h3>
@@ -621,9 +667,15 @@ export default function LiveLogView({
               {modal === 'course' && t('logs.live_course_btn')}
               {modal === 'fuel' && t('logs.live_fuel_btn')}
               {modal === 'water' && t('logs.live_water_btn')}
+              {modal === 'sog' && t('logs.live_sog_btn')}
+              {modal === 'stw' && t('logs.live_stw_btn')}
             </h3>
+            {modal === 'sog' && (
+              <p className="live-log-modal-hint">{t('logs.live_sog_hint')}</p>
+            )}
             <input
               type="text"
+              inputMode="decimal"
               className="input-text"
               value={valueInput}
               onChange={(e) => setValueInput(e.target.value)}
@@ -634,7 +686,9 @@ export default function LiveLogView({
                       : modal === 'sea_state' ? t('logs.live_sea_state_placeholder')
                         : modal === 'course' ? t('logs.live_course_placeholder')
                           : modal === 'fuel' ? t('logs.live_fuel_placeholder')
-                            : t('logs.live_water_placeholder')
+                            : modal === 'water' ? t('logs.live_water_placeholder')
+                              : modal === 'sog' ? t('logs.live_sog_placeholder')
+                                : t('logs.live_stw_placeholder')
               }
               autoFocus
               onKeyDown={(e) => { if (e.key === 'Enter') confirmValueModal() }}
diff --git a/client/src/i18n/locales/da.json b/client/src/i18n/locales/da.json
index 5c621c1..d530476 100644
--- a/client/src/i18n/locales/da.json
+++ b/client/src/i18n/locales/da.json
@@ -209,8 +209,8 @@
       "live_stream_label": "Hændelseslog",
       "live_stream_title": "Journal",
       "live_no_events": "Ingen indtastninger endnu — tryk på en handling.",
-      "live_motor_start": "Motor start",
-      "live_motor_stop": "Motor stop",
+      "live_motor_start": "Motor Start",
+      "live_motor_stop": "Motor Stop",
       "live_cast_off": "Afsejling",
       "live_moor": "Anløb",
       "live_sails_btn": "Sejl",
@@ -251,6 +251,13 @@
       "live_course_placeholder": "f.eks. 245",
       "live_fuel_placeholder": "Optankede liter",
       "live_water_placeholder": "Optankede liter",
+      "live_sog_btn": "SOG",
+      "live_stw_btn": "STW",
+      "live_sog_entry": "SOG {{speed}} kn",
+      "live_stw_entry": "STW {{speed}} kn",
+      "live_sog_placeholder": "f.eks. 5,2",
+      "live_stw_placeholder": "f.eks. 4,8",
+      "live_sog_hint": "Fart over grund (kn) — GPS-værdi forudfyldes, hvis tilgængelig.",
       "delete_entry": "Slet tag",
       "delete_confirm": "Er du sikker på, at du vil slette denne rejsedag permanent?",
       "carry_over_tanks_title": "Overføre data fra den foregående dag?",
diff --git a/client/src/i18n/locales/de.json b/client/src/i18n/locales/de.json
index 72b9387..4b9bb8c 100644
--- a/client/src/i18n/locales/de.json
+++ b/client/src/i18n/locales/de.json
@@ -209,8 +209,8 @@
       "live_stream_label": "Ereignisprotokoll",
       "live_stream_title": "Journal",
       "live_no_events": "Noch keine Einträge — tippe auf eine Aktion.",
-      "live_motor_start": "Motor start",
-      "live_motor_stop": "Motor stop",
+      "live_motor_start": "Motor Start",
+      "live_motor_stop": "Motor Stop",
       "live_cast_off": "Ablegen",
       "live_moor": "Anlegen",
       "live_sails_btn": "Segel",
@@ -251,6 +251,13 @@
       "live_course_placeholder": "z. B. 245",
       "live_fuel_placeholder": "Nachgefüllte Liter",
       "live_water_placeholder": "Nachgefüllte Liter",
+      "live_sog_btn": "SOG",
+      "live_stw_btn": "STW",
+      "live_sog_entry": "SOG {{speed}} kn",
+      "live_stw_entry": "STW {{speed}} kn",
+      "live_sog_placeholder": "z. B. 5,2",
+      "live_stw_placeholder": "z. B. 4,8",
+      "live_sog_hint": "Fahrt über Grund (kn) — GPS-Wert wird vorgefüllt, wenn verfügbar.",
       "delete_entry": "Tag löschen",
       "delete_confirm": "Bist du sicher, dass du diesen Reisetag unwiderruflich löschen möchtest?",
       "carry_over_tanks_title": "Daten vom Vortag übernehmen?",
diff --git a/client/src/i18n/locales/en.json b/client/src/i18n/locales/en.json
index 19055e4..449dc76 100644
--- a/client/src/i18n/locales/en.json
+++ b/client/src/i18n/locales/en.json
@@ -209,8 +209,8 @@
       "live_stream_label": "Event log",
       "live_stream_title": "Journal",
       "live_no_events": "No entries yet — tap an action.",
-      "live_motor_start": "Engine start",
-      "live_motor_stop": "Engine stop",
+      "live_motor_start": "Engine Start",
+      "live_motor_stop": "Engine Stop",
       "live_cast_off": "Cast off",
       "live_moor": "Moor",
       "live_sails_btn": "Sails",
@@ -251,6 +251,13 @@
       "live_course_placeholder": "e.g. 245",
       "live_fuel_placeholder": "Liters refilled",
       "live_water_placeholder": "Liters refilled",
+      "live_sog_btn": "SOG",
+      "live_stw_btn": "STW",
+      "live_sog_entry": "SOG {{speed}} kn",
+      "live_stw_entry": "STW {{speed}} kn",
+      "live_sog_placeholder": "e.g. 5.2",
+      "live_stw_placeholder": "e.g. 4.8",
+      "live_sog_hint": "Speed over ground (kn) — prefilled from GPS when available.",
       "delete_entry": "Delete Day",
       "delete_confirm": "Are you sure you want to permanently delete this travel day?",
       "carry_over_tanks_title": "Carry over from previous day?",
diff --git a/client/src/i18n/locales/nb.json b/client/src/i18n/locales/nb.json
index 6133937..c3ed7a3 100644
--- a/client/src/i18n/locales/nb.json
+++ b/client/src/i18n/locales/nb.json
@@ -209,8 +209,8 @@
       "live_stream_label": "Hendelseslogg",
       "live_stream_title": "Journal",
       "live_no_events": "Ingen oppføringer ennå — trykk på en handling.",
-      "live_motor_start": "Motor start",
-      "live_motor_stop": "Motor stopp",
+      "live_motor_start": "Motor Start",
+      "live_motor_stop": "Motor Stopp",
       "live_cast_off": "Avreise",
       "live_moor": "Anløp",
       "live_sails_btn": "Seil",
@@ -251,6 +251,13 @@
       "live_course_placeholder": "f.eks. 245",
       "live_fuel_placeholder": "Påfylte liter",
       "live_water_placeholder": "Påfylte liter",
+      "live_sog_btn": "SOG",
+      "live_stw_btn": "STW",
+      "live_sog_entry": "SOG {{speed}} kn",
+      "live_stw_entry": "STW {{speed}} kn",
+      "live_sog_placeholder": "f.eks. 5,2",
+      "live_stw_placeholder": "f.eks. 4,8",
+      "live_sog_hint": "Fart over grunn (kn) — GPS-verdi fylles inn hvis tilgjengelig.",
       "delete_entry": "Slett tagg",
       "delete_confirm": "Er du sikker på at du vil slette denne reisedagen permanent?",
       "carry_over_tanks_title": "Overføre data fra dagen før?",
diff --git a/client/src/i18n/locales/sv.json b/client/src/i18n/locales/sv.json
index 989fc72..cd5d75e 100644
--- a/client/src/i18n/locales/sv.json
+++ b/client/src/i18n/locales/sv.json
@@ -209,8 +209,8 @@
       "live_stream_label": "Händelselogg",
       "live_stream_title": "Journal",
       "live_no_events": "Inga poster ännu — tryck på en åtgärd.",
-      "live_motor_start": "Motor start",
-      "live_motor_stop": "Motor stopp",
+      "live_motor_start": "Motor Start",
+      "live_motor_stop": "Motor Stopp",
       "live_cast_off": "Avgång",
       "live_moor": "Anlöp",
       "live_sails_btn": "Segel",
@@ -251,6 +251,13 @@
       "live_course_placeholder": "t.ex. 245",
       "live_fuel_placeholder": "Påfyllda liter",
       "live_water_placeholder": "Påfyllda liter",
+      "live_sog_btn": "SOG",
+      "live_stw_btn": "STW",
+      "live_sog_entry": "SOG {{speed}} kn",
+      "live_stw_entry": "STW {{speed}} kn",
+      "live_sog_placeholder": "t.ex. 5,2",
+      "live_stw_placeholder": "t.ex. 4,8",
+      "live_sog_hint": "Fart över grund (kn) — GPS-värde fylls i om tillgängligt.",
       "delete_entry": "Ta bort tagg",
       "delete_confirm": "Är du säker på att du vill radera den här resedagen permanent?",
       "carry_over_tanks_title": "Överföra data från föregående dag?",
diff --git a/client/src/utils/formatEventSummary.test.ts b/client/src/utils/formatEventSummary.test.ts
index b24b8a3..1215084 100644
--- a/client/src/utils/formatEventSummary.test.ts
+++ b/client/src/utils/formatEventSummary.test.ts
@@ -4,6 +4,7 @@ import {
   LIVE_EVENT_CODES,
   liveCommentRemark,
   liveSailsRemark,
+  liveSogRemark,
   parseLiveCommentRemark,
   parseLiveSailsRemark
 } from './liveEventCodes.js'
@@ -12,8 +13,8 @@ import { normalizeLogEvent } from './logEntryPayload.js'
 
 const t = (key: string, opts?: Record<string, unknown>) => {
   const map: Record<string, string> = {
-    'logs.live_motor_start': 'Motor start',
-    'logs.live_motor_stop': 'Motor stop',
+    'logs.live_motor_start': 'Motor Start',
+    'logs.live_motor_stop': 'Motor Stop',
     'logs.live_cast_off': 'Cast off',
     'logs.live_moor': 'Moor',
     'logs.live_sails': `Sails: ${opts?.sails ?? ''}`,
@@ -24,6 +25,8 @@ const t = (key: string, opts?: Record<string, unknown>) => {
     'logs.live_pressure_entry': `Pressure ${opts?.value} hPa`,
     'logs.live_wind_entry': `Wind ${opts?.value}`,
     'logs.live_course_entry': `Course ${opts?.course}`,
+    'logs.live_sog_entry': `SOG ${opts?.speed} kn`,
+    'logs.live_stw_entry': `STW ${opts?.speed} kn`,
     'logs.event_mgk': 'Course',
     'logs.event_wind_pressure': 'Pressure'
   }
@@ -57,7 +60,7 @@ describe('liveEventCodes', () => {
 describe('formatEventSummary', () => {
   it('formats live motor start', () => {
     const event = normalizeLogEvent({ time: '08:10', remarks: LIVE_EVENT_CODES.MOTOR_START })
-    expect(formatEventSummary(event, t)).toBe('Motor start')
+    expect(formatEventSummary(event, t)).toBe('Motor Start')
   })
 
   it('formats sails remark', () => {
@@ -87,4 +90,20 @@ describe('formatEventSummary', () => {
     })
     expect(formatEventSummary(event, t)).toBe('Pressure 1013 hPa')
   })
+
+  it('formats SOG entry', () => {
+    const event = normalizeLogEvent({
+      time: '10:15',
+      remarks: liveSogRemark('5.2')
+    })
+    expect(formatEventSummary(event, t)).toBe('SOG 5.2 kn')
+  })
+
+  it('formats STW entry', () => {
+    const event = normalizeLogEvent({
+      time: '10:20',
+      remarks: '__live:stw:4.8'
+    })
+    expect(formatEventSummary(event, t)).toBe('STW 4.8 kn')
+  })
 })
diff --git a/client/src/utils/formatEventSummary.ts b/client/src/utils/formatEventSummary.ts
index 315b22a..05a8d84 100644
--- a/client/src/utils/formatEventSummary.ts
+++ b/client/src/utils/formatEventSummary.ts
@@ -6,6 +6,8 @@ import {
   parseLiveFuelRemark,
   parseLivePrecipRemark,
   parseLiveSailsRemark,
+  parseLiveSogRemark,
+  parseLiveStwRemark,
   parseLiveTempRemark,
   parseLiveWaterRemark
 } from './liveEventCodes.js'
@@ -36,6 +38,12 @@ export function formatEventSummary(event: LogEventPayload, t: TFunction): string
   const water = parseLiveWaterRemark(code)
   if (water) return t('logs.live_water_entry', { liters: water })
 
+  const sog = parseLiveSogRemark(code)
+  if (sog) return t('logs.live_sog_entry', { speed: sog })
+
+  const stw = parseLiveStwRemark(code)
+  if (stw) return t('logs.live_stw_entry', { speed: stw })
+
   if (code === LIVE_EVENT_CODES.FIX || code === LIVE_EVENT_CODES.AUTO_POSITION) {
     if (event.gpsLat && event.gpsLng) {
       const label = code === LIVE_EVENT_CODES.AUTO_POSITION
diff --git a/client/src/utils/geolocation.ts b/client/src/utils/geolocation.ts
index fc614db..52048bc 100644
--- a/client/src/utils/geolocation.ts
+++ b/client/src/utils/geolocation.ts
@@ -1,6 +1,10 @@
+const MPS_TO_KNOTS = 1.9438444924406
+
 export interface GeoCoordinates {
   lat: string
   lng: string
+  /** SOG from GPS when available (kn), otherwise null. */
+  speedKn: number | null
 }
 
 export function getCurrentPosition(timeoutMs = 15000): Promise<GeoCoordinates> {
@@ -12,9 +16,13 @@ export function getCurrentPosition(timeoutMs = 15000): Promise<GeoCoordinates> {
 
     navigator.geolocation.getCurrentPosition(
       (pos) => {
+        const speedKn = pos.coords.speed != null && Number.isFinite(pos.coords.speed)
+          ? Number((pos.coords.speed * MPS_TO_KNOTS).toFixed(1))
+          : null
         resolve({
           lat: pos.coords.latitude.toFixed(6),
-          lng: pos.coords.longitude.toFixed(6)
+          lng: pos.coords.longitude.toFixed(6),
+          speedKn
         })
       },
       (err) => reject(err),
diff --git a/client/src/utils/liveEventCodes.ts b/client/src/utils/liveEventCodes.ts
index 230081e..78ff22b 100644
--- a/client/src/utils/liveEventCodes.ts
+++ b/client/src/utils/liveEventCodes.ts
@@ -38,6 +38,14 @@ export function liveWaterRemark(liters: string): string {
   return `__live:water:${liters}`
 }
 
+export function liveSogRemark(speedKn: string): string {
+  return `__live:sog:${speedKn}`
+}
+
+export function liveStwRemark(speedKn: string): string {
+  return `__live:stw:${speedKn}`
+}
+
 export function parseLiveSailsRemark(remarks: string): string | null {
   const prefix = '__live:sails:'
   return remarks.startsWith(prefix) ? remarks.slice(prefix.length) : null
@@ -68,6 +76,16 @@ export function parseLiveWaterRemark(remarks: string): string | null {
   return remarks.startsWith(prefix) ? remarks.slice(prefix.length) : null
 }
 
+export function parseLiveSogRemark(remarks: string): string | null {
+  const prefix = '__live:sog:'
+  return remarks.startsWith(prefix) ? remarks.slice(prefix.length) : null
+}
+
+export function parseLiveStwRemark(remarks: string): string | null {
+  const prefix = '__live:stw:'
+  return remarks.startsWith(prefix) ? remarks.slice(prefix.length) : null
+}
+
 /** Derive motor running state from event history (survives reload). */
 export function isMotorRunningFromEvents(
   events: Array<{ remarks: string }>,