Johnson Sea Link was the name of a deep-sea scientific research submersible built by Edwin Albert Link in 1971. Link built the submersible at the request of his friend Seward Johnson, founder of the Harbor Branch Oceanographic Institute. It was the successor to Link's previous submersible, Deep Diver, which had been determined to be unsafe for use at great depths or in extremely cold temperatures.The Johnson Sea Link carried a crew of four in two separate compartments.