diff --git a/frontend/tests/log.spec.ts b/frontend/tests/log.spec.ts
index d2789c5..efa53f0 100644
--- a/frontend/tests/log.spec.ts
+++ b/frontend/tests/log.spec.ts
@@ -102,6 +102,28 @@ test("Cox can start and finish trip", async ({ page }, testInfo) => {
   await expect(page.locator('body')).toContainText('(cox2)');
   await expect(page.locator('body')).toContainText('Ottensheim (25 km)');
   await expect(page.locator('body')).toContainText('Ruderer: cox2, rower2');
+
+
+  //Ausloggen...
+  await page.getByRole('banner').getByRole('link', { name: 'Logbuch' }).click();
+  await page.getByRole('link', { name: 'Ausloggen' }).click();
+  // Login as admin
+  await page.getByPlaceholder("Name").click();
+  await page.getByPlaceholder("Name").fill("main");
+  await page.getByPlaceholder("Name").press("Tab");
+  await page.getByPlaceholder("Passwort").fill("admin");
+  await page.getByPlaceholder("Passwort").press("Enter");
+
+  await page.goto("/log/show");
+  await page.getByText('(cox2)').click();
+  page.once("dialog", (dialog) => {
+    dialog.accept().catch(() => {});
+  });
+  await page.getByRole('link', { name: 'Löschen' }).click();
+
+  //Ausloggen...
+  await page.getByRole('banner').getByRole('link', { name: 'Logbuch' }).click();
+  await page.getByRole('link', { name: 'Ausloggen' }).click();
 });
 
 test("Kiosk can start and cancel trip", async ({ page }, testInfo) => {
@@ -189,6 +211,29 @@ test("Kiosk can start and finish trip", async ({ page }, testInfo) => {
   await expect(page.locator('body')).toContainText('(cox2)');
   await expect(page.locator('body')).toContainText('Ottensheim (25 km)');
   await expect(page.locator('body')).toContainText('Ruderer: cox2, rower2');
+  
+
+
+  //Ausloggen...
+  await page.context().clearCookies();
+  await page.goto("/auth");
+  // Login as admin
+  await page.getByPlaceholder("Name").click();
+  await page.getByPlaceholder("Name").fill("main");
+  await page.getByPlaceholder("Name").press("Tab");
+  await page.getByPlaceholder("Passwort").fill("admin");
+  await page.getByPlaceholder("Passwort").press("Enter");
+
+  await page.goto("/log/show");
+  await page.getByText('(cox2)').click();
+  page.once("dialog", (dialog) => {
+    dialog.accept().catch(() => {});
+  });
+  await page.getByRole('link', { name: 'Löschen' }).click();
+
+  //Ausloggen...
+  await page.getByRole('banner').getByRole('link', { name: 'Logbuch' }).click();
+  await page.getByRole('link', { name: 'Ausloggen' }).click();
 });
 
 test("Cox can start and finish trip with cox steering only", async ({ page }, testInfo) => {
@@ -241,8 +286,31 @@ test("Cox can start and finish trip with cox steering only", async ({ page }, te
 
   await page.goto('/log/show');
   await expect(page.locator('body')).toContainText('cox_only_steering_boat');
-  await expect(page.locator('body')).toContainText('(cox2)');
+  await expect(page.locator('body')).toContainText('(cox2 - handgesteuert)');
   await expect(page.locator('body')).toContainText('Ottensheim (25 km)');
+  
+
+
+  //Ausloggen...
+  await page.getByRole('banner').getByRole('link', { name: 'Logbuch' }).click();
+  await page.getByRole('link', { name: 'Ausloggen' }).click();
+  // Login as admin
+  await page.getByPlaceholder("Name").click();
+  await page.getByPlaceholder("Name").fill("main");
+  await page.getByPlaceholder("Name").press("Tab");
+  await page.getByPlaceholder("Passwort").fill("admin");
+  await page.getByPlaceholder("Passwort").press("Enter");
+
+  await page.goto("/log/show");
+  await page.getByText('(cox2 - handgesteuert)').click();
+  page.once("dialog", (dialog) => {
+    dialog.accept().catch(() => {});
+  });
+  await page.getByRole('link', { name: 'Löschen' }).click();
+
+  //Ausloggen...
+  await page.getByRole('banner').getByRole('link', { name: 'Logbuch' }).click();
+  await page.getByRole('link', { name: 'Ausloggen' }).click();
 });
 
 test("Kiosk can start and finish trip in one stop", async ({ page }, testInfo) => {
@@ -289,4 +357,27 @@ test("Kiosk can start and finish trip in one stop", async ({ page }, testInfo) =
   await expect(page.locator('body')).toContainText('(cox2)');
   await expect(page.locator('body')).toContainText('a (1 km)');
   await expect(page.locator('body')).toContainText('Ruderer: cox2, rower2');
+  
+
+
+  //Ausloggen...
+  await page.context().clearCookies();
+  await page.goto("/auth");
+  // Login as admin
+  await page.getByPlaceholder("Name").click();
+  await page.getByPlaceholder("Name").fill("main");
+  await page.getByPlaceholder("Name").press("Tab");
+  await page.getByPlaceholder("Passwort").fill("admin");
+  await page.getByPlaceholder("Passwort").press("Enter");
+
+  await page.goto("/log/show");
+  await page.getByText('(cox2)').click();
+  page.once("dialog", (dialog) => {
+    dialog.accept().catch(() => {});
+  });
+  await page.getByRole('link', { name: 'Löschen' }).click();
+
+  //Ausloggen...
+  await page.getByRole('banner').getByRole('link', { name: 'Logbuch' }).click();
+  await page.getByRole('link', { name: 'Ausloggen' }).click();
 });
diff --git a/seeds.sql b/seeds.sql
index 1c42ed3..b413278 100644
--- a/seeds.sql
+++ b/seeds.sql
@@ -10,6 +10,7 @@ INSERT INTO "role" (name) VALUES ('Vorstand');
 INSERT INTO "role" (name) VALUES ('Bootsführer');
 INSERT INTO "role" (name) VALUES ('schnupperant');
 INSERT INTO "role" (name) VALUES ('kassier');
+INSERT INTO "role" (name) VALUES ('schriftfuehrer');
 INSERT INTO "role" (name) VALUES ('no-einschreibgebuehr');
 INSERT INTO "user" (name, pw) VALUES('admin', '$argon2id$v=19$m=19456,t=2,p=1$dS/X5/sPEKTj4Rzs/CuvzQ$4P4NCw4Ukhv80/eQYTsarHhnw61JuL1KMx/L9dm82YM');
 INSERT INTO "user_role" (user_id, role_id) VALUES(1,1);
@@ -37,7 +38,12 @@ INSERT INTO "user_role" (user_id, role_id) VALUES(8,5);
 INSERT INTO "user_role" (user_id, role_id) VALUES(8,7);
 INSERT INTO "user" (name,  pw) VALUES('Vorstandsmitglied', '$argon2id$v=19$m=19456,t=2,p=1$dS/X5/sPEKTj4Rzs/CuvzQ$jWKzDmI0jqT2dqINFt6/1NjVF4Dx15n07PL1ZMBmFsY');
 INSERT INTO "user_role" (user_id, role_id) VALUES(9,5);
-INSERT INTO "user_role" (user_id, role_id) VALUES(9,9);
+INSERT INTO "user" (name, pw) VALUES('main', '$argon2id$v=19$m=19456,t=2,p=1$dS/X5/sPEKTj4Rzs/CuvzQ$4P4NCw4Ukhv80/eQYTsarHhnw61JuL1KMx/L9dm82YM');
+INSERT INTO "user_role" (user_id, role_id) VALUES(10,1);
+INSERT INTO "user_role" (user_id, role_id) VALUES(10,2);
+INSERT INTO "user_role" (user_id, role_id) VALUES(10,5);
+INSERT INTO "user_role" (user_id, role_id) VALUES(10,6);
+INSERT INTO "user_role" (user_id, role_id) VALUES(10,9);
 
 INSERT INTO "trip_details" (planned_starting_time, max_people, day, notes) VALUES('10:00', 2, '1970-01-01', 'trip_details for a planned event');
 INSERT INTO "planned_event" (name, planned_amount_cox, trip_details_id) VALUES('test-planned-event', 2, 1);
diff --git a/src/model/boat.rs b/src/model/boat.rs
index fe87f65..a851180 100644
--- a/src/model/boat.rs
+++ b/src/model/boat.rs
@@ -1,5 +1,6 @@
 use std::ops::DerefMut;
 
+use chrono::NaiveDateTime;
 use itertools::Itertools;
 use rocket::serde::{Deserialize, Serialize};
 use rocket::FromForm;
@@ -391,6 +392,39 @@ ORDER BY amount_seats DESC
         .await
         .ok()
     }
+
+    pub async fn on_water_between(
+        &self,
+        db: &mut Transaction<'_, Sqlite>,
+        dep: NaiveDateTime,
+        arr: NaiveDateTime,
+    ) -> bool {
+        let dep = dep.format("%Y-%m-%dT%H:%M").to_string();
+        let arr = arr.format("%Y-%m-%dT%H:%M").to_string();
+
+        sqlx::query!(
+            "SELECT COUNT(*) AS overlap_count
+FROM logbook
+WHERE boat_id = ?
+  AND (
+    (departure <= ? AND arrival >= ?)  -- Existing entry covers the entire new period
+    OR (departure >= ? AND departure < ?)  -- Existing entry starts during the new period
+    OR (arrival > ? AND arrival <= ?)  -- Existing entry ends during the new period
+  );",
+            self.id,
+            arr,
+            arr,
+            dep,
+            dep,
+            dep,
+            arr
+        )
+        .fetch_one(db.deref_mut())
+        .await
+        .unwrap()
+        .overlap_count
+            > 0
+    }
 }
 
 #[cfg(test)]
diff --git a/src/model/logbook.rs b/src/model/logbook.rs
index cac3fdc..a45a3cc 100644
--- a/src/model/logbook.rs
+++ b/src/model/logbook.rs
@@ -142,6 +142,7 @@ pub enum LogbookUpdateError {
     TooFast(i64, i64),
     AlreadyFinalized,
     ExternalSteeringPersonMustSteerOrShipmaster,
+    BoatAlreadyOnWater,
 }
 
 #[derive(Debug, PartialEq)]
@@ -196,6 +197,7 @@ impl From<LogbookUpdateError> for LogbookCreateError {
             LogbookUpdateError::ExternalSteeringPersonMustSteerOrShipmaster => {
                 LogbookCreateError::ExternalSteeringPersonMustSteerOrShipmaster
             }
+            LogbookUpdateError::BoatAlreadyOnWater => LogbookCreateError::BoatAlreadyOnWater,
         }
     }
 }
@@ -573,6 +575,12 @@ ORDER BY departure DESC
             return Err(LogbookUpdateError::ArrivalNotAfterDeparture);
         }
 
+        if !boat.external {
+            if boat.on_water_between(db, dep, arr).await {
+                return Err(LogbookUpdateError::BoatAlreadyOnWater);
+            };
+        }
+
         let duration_in_mins = (arr.and_utc().timestamp() - dep.and_utc().timestamp()) / 60;
         // Not possible to row < 1 min / 500 m = < 2 min / km
         let possible_distance_km = duration_in_mins / 2;
diff --git a/src/model/user.rs b/src/model/user.rs
index 6a450f5..49d828c 100644
--- a/src/model/user.rs
+++ b/src/model/user.rs
@@ -1106,7 +1106,7 @@ mod test {
     fn test_cox() {
         let pool = testdb!();
         let res = User::cox(&pool).await;
-        assert_eq!(res.len(), 3);
+        assert_eq!(res.len(), 4);
     }
 
     #[sqlx::test]
diff --git a/src/tera/log.rs b/src/tera/log.rs
index 98e49d5..b21b78a 100644
--- a/src/tera/log.rs
+++ b/src/tera/log.rs
@@ -347,6 +347,7 @@ async fn home_logbook(
         Err(LogbookUpdateError::TooFast(km, min)) => Flash::error(Redirect::to("/log"), format!("KM zu groß für die eingegebene Dauer ({km} km in {min} Minuten). Bitte überprüfe deine Start- und Endzeit und versuche es erneut.")),
         Err(LogbookUpdateError::AlreadyFinalized) => Flash::error(Redirect::to("/log"), "Logbucheintrag wurde bereits abgeschlossen."),
         Err(LogbookUpdateError::ExternalSteeringPersonMustSteerOrShipmaster) => Flash::error(Redirect::to("/log"), "Wenn du eine 'Externe Steuerperson' hinzufügst, muss diese steuern oder Schiffsführer sein!"),
+        Err(LogbookUpdateError::BoatAlreadyOnWater) => Flash::error(Redirect::to("/log"), "Das Boot war in diesem Zeitraum schon am Wasser. Bitte überprüfe das Datum und die Zeit."),
         Err(e) => Flash::error(
             Redirect::to("/log"),
             format!("Eintrag {logbook_id} konnte nicht abgesendet werden (Fehler: {e:?})!"),