diff --git a/entities/ISerializable.h b/entities/ISerializable.h
index b1d5022..f116eee 100644
--- a/entities/ISerializable.h
+++ b/entities/ISerializable.h
@@ -8,16 +8,6 @@ class ISerializable {
 public:
     virtual void serialize(QDataStream &output) = 0;
     virtual void deserialize(QDataStream &input) = 0;
-
-    friend QDataStream &operator<<(QDataStream &output, ISerializable &s) {
-        s.serialize(output);
-        return output;
-    }
-
-    friend QDataStream &operator>>(QDataStream  &input, ISerializable &s) {
-        s.deserialize(input);
-        return input;
-    }
 };
 
 #endif // ISERIALIZABLE_H
diff --git a/entities/cargo_entity.cpp b/entities/cargo_entity.cpp
index b24a177..27d37f8 100644
--- a/entities/cargo_entity.cpp
+++ b/entities/cargo_entity.cpp
@@ -1,6 +1,6 @@
 #include "cargo_entity.h"
 
-cargo_entity::cargo_entity(const QString &title, int volume) : _title(title), _volume(volume) {
+cargo_entity::cargo_entity(const QString &title, unsigned int volume) : _title(title), _volume(volume) {
     this->_id = volume;
     auto hash = QCryptographicHash::hash(title.toLocal8Bit(), QCryptographicHash::Md5);
     for (auto bit : hash) {
diff --git a/entities/cargo_entity.h b/entities/cargo_entity.h
index cbf00c8..ab5e043 100644
--- a/entities/cargo_entity.h
+++ b/entities/cargo_entity.h
@@ -15,7 +15,7 @@ private:
 
 public:
     cargo_entity() = default;
-    cargo_entity(const QString &title, int volume);
+    cargo_entity(const QString &title, unsigned int volume);
 
     unsigned long long id();
     QString title();
diff --git a/entities/storage_entity.cpp b/entities/storage_entity.cpp
index 83f65a1..31f34d6 100644
--- a/entities/storage_entity.cpp
+++ b/entities/storage_entity.cpp
@@ -21,9 +21,17 @@ const QVector<cargo_entity> storage_entity::cargo() {
 }
 
 void storage_entity::serialize(QDataStream &output) {
-    output << this->_id << this->_capacity << this->_cargo;
+    output << this->_id << this->_capacity << this->_cargo.size();
+    for (auto item : this->_cargo) {
+        item.serialize(output);
+    }
 }
 
 void storage_entity::deserialize(QDataStream &input) {
-    input >> this->_id >> this->_capacity >> this->_cargo;
+    int icnt;
+    input >> this->_id >> this->_capacity >> icnt;
+    this->_cargo.resize(icnt);
+    for (int i = 0; i < icnt; i++) {
+        this->_cargo[i].deserialize(input);
+    }
 }
diff --git a/entities/vessel_entity.cpp b/entities/vessel_entity.cpp
index a5b99a0..aeafd91 100644
--- a/entities/vessel_entity.cpp
+++ b/entities/vessel_entity.cpp
@@ -24,9 +24,21 @@ const QVector<cargo_entity> vessel_entity::cargo() {
 }
 
 void vessel_entity::serialize(QDataStream &output) {
-    output << this->_id << this->_harbor << this->_capacity << this->_cargo;
+    output << this->_id;
+    this->_harbor.serialize(output);
+    output << this->_capacity << this->_cargo.size();
+    for (auto item : this->_cargo) {
+        item.serialize(output);
+    }
 }
 
 void vessel_entity::deserialize(QDataStream &input) {
-    input >> this->_id >> this->_harbor >> this->_capacity >> this->_cargo;
+    input >> this->_id;
+    this->_harbor.deserialize(input);
+    int icnt;
+    input >> this->_capacity >> icnt;
+    this->_cargo.resize(icnt);
+    for (int i = 0; i < icnt; i++) {
+        this->_cargo[i].deserialize(input);
+    }
 }