diff --git a/src/modules/bottle_drop/bottle_drop.cpp b/src/modules/bottle_drop/bottle_drop.cpp
index 6d24e5d2d1..e0bcbc6e9e 100644
--- a/src/modules/bottle_drop/bottle_drop.cpp
+++ b/src/modules/bottle_drop/bottle_drop.cpp
@@ -223,7 +223,7 @@ BottleDrop::start()
 	_main_task = task_spawn_cmd("bottle_drop",
 				    SCHED_DEFAULT,
 				    SCHED_PRIORITY_DEFAULT + 15,
-				    2048,
+				    1500,
 				    (main_t)&BottleDrop::task_main_trampoline,
 				    nullptr);
 
diff --git a/src/modules/bottle_drop/module.mk b/src/modules/bottle_drop/module.mk
index 9602288790..df9f5473b0 100644
--- a/src/modules/bottle_drop/module.mk
+++ b/src/modules/bottle_drop/module.mk
@@ -41,3 +41,5 @@ SRCS			= bottle_drop.cpp \
 			  bottle_drop_params.c
 
 MAXOPTIMIZATION	 = -Os
+
+MODULE_STACKSIZE = 1200
diff --git a/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp b/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
index 00900c995f..e7805daa91 100644
--- a/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
+++ b/src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
@@ -1560,7 +1560,7 @@ FixedwingEstimator::start()
 	_estimator_task = task_spawn_cmd("ekf_att_pos_estimator",
 					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_MAX - 40,
-					 5000,
+					 7500,
 					 (main_t)&FixedwingEstimator::task_main_trampoline,
 					 nullptr);
 
diff --git a/src/modules/mavlink/mavlink_main.cpp b/src/modules/mavlink/mavlink_main.cpp
index c251dd3b2c..fb9f65cf50 100644
--- a/src/modules/mavlink/mavlink_main.cpp
+++ b/src/modules/mavlink/mavlink_main.cpp
@@ -1636,7 +1636,7 @@ Mavlink::start(int argc, char *argv[])
 	task_spawn_cmd(buf,
 		       SCHED_DEFAULT,
 		       SCHED_PRIORITY_DEFAULT,
-		       2900,
+		       2800,
 		       (main_t)&Mavlink::start_helper,
 		       (const char **)argv);
 
diff --git a/src/modules/navigator/navigator_main.cpp b/src/modules/navigator/navigator_main.cpp
index 3ca6ac2c0e..10a4ee88f6 100644
--- a/src/modules/navigator/navigator_main.cpp
+++ b/src/modules/navigator/navigator_main.cpp
@@ -499,7 +499,7 @@ Navigator::start()
 	_navigator_task = task_spawn_cmd("navigator",
 					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_DEFAULT + 20,
-					 2000,
+					 1800,
 					 (main_t)&Navigator::task_main_trampoline,
 					 nullptr);