A British marine workwear coverall in blue color is a type of protective clothing worn by workers in the marine industry. It is typically made of ripstop material, which is a type of fabric that is reinforced with a special type of thread that makes it resistant to tearing and ripping. This feature makes it ideal for use in harsh and rugged environments, as it is able to withstand the wear and tear of daily use. The blue color is likely chosen for visibility and safety on the job.