Beware of exposed prop shaft.
A substantial 10 metre yacht had recently been recommissioned after her winter lay up. The engine had been run and the owner had nipped up the stern gland during one short trip.
On a later occasion, the owner was on board with his son, and was motoring the boat a few cables from her mooring to a marina to take on stores for a weekend’s sailing. The weather was excellent, with negligible wind and a flat calm sea.
During this relatively short run, the owner decided to again check the stern gland. After checking the cuffs of his jacket were properly secured, he lifted the hatch to the stern gland/propshaft space. To gain the best indication of the rate of water ingress through the stern gland, he decided to remove a small amount of water that had collected in the bilge space beneath. To do this, he used a sponge, wringing it out once saturated. He did this a couple of times without problems.
Unfortunately, on the next occasion, the left sleeve of his jacket became entangled with a coupling on the rotating propeller shaft (see photograph). His arm was dragged around the shaft and, before he could free it, was very seriously injured.
The owner’s shouts were heard by his son on the helm, who promptly stopped the engine and immediately used his mobile telephone to dial 999 and ask for coastguard assistance. He then used the boat’s first-aid kit to dress his father’s arm, using a wooden spatula from the galley as a splint and cottonwool pads to stem the flow of blood. The injury was serious, with a length of broken bone exposed.
Emergency services were very quickly on scene, with helicopter and lifeboat both available to evacuate the casualty. It was decided to use the lifeboat to transfer the owner to an ambulance and then hospital. Because of the benign weather conditions, the owner was able to climb, unaided, from his boat onto the lifeboat.
The Lessons
1. However smooth and polished they might sometimes appear, spinning propeller shafts should still be considered as rotating machinery, capable of causing serious injury. It is always safest to stop machinery whenever hands, clothing etc. are close to exposed moving parts.
2. The securing arrangements of this coupling could have been rather less hazardous. The square-headed screws, shown in the figure with ‘locking wire’ through their heads, might reasonably be replaced by items that protrude less. ‘Grub’ screws of suitable length, tightened with a hexagonal ‘Allen’ key, could be fitted so that their ends are flush with the coupling’s outer surface.
Alternatively, or even additionally, a metal guard over the shaft and coupling would keep personnel safe and would prevent other parts of the boat’s safety critical systems, such as water or exhaust hoses, from coming into contact with these moving parts.
3. The response of the owner’s son in this emergency showed great presence of mind. In particular, his use of the spatula as a splint was an example of clear thinking that we all would hope to demonstrate in such an emergency; but probably with less success.
Reproduced by kind permission of the Marine Accident Investigation Branch. Originally published in MAIB Safety Digest 1/2005. www.maib.dft.gov.uk
