I haven't seen pictures of the torpedo in question, but I can assure you of two things:
1. Barnacles develop pretty damn quickly on unprotected surfaces - if one of our RHIBs is in the water for more than five days (it happens when we're in port), then it's gonna need to have the barnacles scrapped off. It's why they were the bane of all wooden ships as they degraded their ability to move quickly through the water.
2. N. Korean torpedoes are cheap - IE: no protective coatings. It's why they have a selling point with countries like Russia and China.
1. Barnacles develop pretty damn quickly on unprotected surfaces - if one of our RHIBs is in the water for more than five days (it happens when we're in port), then it's gonna need to have the barnacles scrapped off. It's why they were the bane of all wooden ships as they degraded their ability to move quickly through the water.
2. N. Korean torpedoes are cheap - IE: no protective coatings. It's why they have a selling point with countries like Russia and China.