From aa519879a76e82d870bb1353eee7dfdf8ea07764 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Janiszewski?= <janisozaur@gmail.com>
Date: Sun, 15 Jun 2025 23:05:55 +0200
Subject: [PATCH 1/2] Fix #24617: Prevent hired boat with 0 speed causing
 division by 0

---
 distribution/changelog.txt    | 1 +
 src/openrct2/ride/Vehicle.cpp | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/distribution/changelog.txt b/distribution/changelog.txt
index 33292ea8b6..3c3b99be94 100644
--- a/distribution/changelog.txt
+++ b/distribution/changelog.txt
@@ -16,6 +16,7 @@
 - Fix: [#24576] It is possible to edit open rides in certain circumstances.
 - Fix: [#24589] Music tab doesn’t fully render in multiplayer.
 - Fix: [#24615] Blank strings in Windows installer.
+- Fix: [#24617] ‘Divide by zero’ error when updating boat hire acceleration.
 
 0.4.23 (2025-06-07)
 ------------------------------------------------------------------------
diff --git a/src/openrct2/ride/Vehicle.cpp b/src/openrct2/ride/Vehicle.cpp
index 698d9627fa..dc7f255c6e 100644
--- a/src/openrct2/ride/Vehicle.cpp
+++ b/src/openrct2/ride/Vehicle.cpp
@@ -3920,7 +3920,10 @@ void Vehicle::UpdateMotionBoatHire()
             }
             eax -= velocity;
             edx = powered_acceleration * 2;
-            ecx += (eax * edx) / ebx;
+            if (ebx != 0)
+            {
+                ecx += (eax * edx) / ebx;
+            }
         }
         acceleration = ecx;
     }

From 18543caf58d66ad9d5aaf1c9ff92a917af2b7b6b Mon Sep 17 00:00:00 2001
From: Gymnasiast <m.o.steenbeek@gmail.com>
Date: Wed, 18 Jun 2025 23:40:07 +0200
Subject: [PATCH 2/2] Rename `ecx` to `newAcceleration`

---
 src/openrct2/ride/Vehicle.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/openrct2/ride/Vehicle.cpp b/src/openrct2/ride/Vehicle.cpp
index dc7f255c6e..74344fad77 100644
--- a/src/openrct2/ride/Vehicle.cpp
+++ b/src/openrct2/ride/Vehicle.cpp
@@ -3909,7 +3909,7 @@ void Vehicle::UpdateMotionBoatHire()
         int32_t curMass = mass == 0 ? 1 : mass;
 
         int32_t eax = ((velocity >> 1) + edx) / curMass;
-        int32_t ecx = -eax;
+        int32_t newAcceleration = -eax;
         if (carEntry->flags & CAR_ENTRY_FLAG_POWERED)
         {
             eax = speed << 14;
@@ -3922,10 +3922,10 @@ void Vehicle::UpdateMotionBoatHire()
             edx = powered_acceleration * 2;
             if (ebx != 0)
             {
-                ecx += (eax * edx) / ebx;
+                newAcceleration += (eax * edx) / ebx;
             }
         }
-        acceleration = ecx;
+        acceleration = newAcceleration;
     }
     // eax = _vehicleMotionTrackFlags;
     // ebx = _vehicleStationIndex;