Complex sentence: The company's submarines were too small and their endurance too limited to cross the oceans on their own and towing them was too risky so Schneider commissioned a purpose-built ship to deliver them safely to their destination.
Split into simpler sentences: The company's submarines were too small and their endurance too limited to cross the oceans on their own. Schneider deemed towing them was too risky so the company commissioned a purpose-built ship to deliver them safely to their destination.