The bruising hammer
Take your time and maybe used less force on vessel connections suggests Marine Safety Forum following a recent injury.
A platform supply ship was called into the platform to discharge water and fuel. Two deck crewmen were on duty. The weather was calm and fine and it was daylight.
The FW hose was sent down to the starboard side amidships. The IP went to take the end cap off the vessel connection. The connection faces aft and is about 1 metre off the deck. He faced the manifold and took a small hand sledge hammer in his right hand and held the cap in his left hand in case it spun and fell to the deck. He struck the cap lugs with force moving the hammer from right to left to turn the cap anti-clockwise. The hammer head glanced off the cap lugs and struck his left hand heavily on the palm at the base of his thumb.