Emergency Kill Cord

Kill Cord (Dead Man)

We all love diving and some of the best diving is done from a dive rigid inflatable boat (RIB). They are great fun, fast and relatively easy to drive in good conditions.
However, imagine one day you are driving your outboard powered RIB in a slightly choppy sea when you hit a freak wave and you and maybe some of your crew are thrown overboard. If the engine does not automatically stop, the best thing that can happen is that the boat speeds away into the distance, running out of petrol before hitting anything, you are recovered unhurt and the boat is amazingly returned to you undamaged. The worse thing that can happen is that the steering goes full lock and the boat starts to circle you at full speed with possible inevitable fatal consequences.


These are real pictures of that actually happening. In the first picture you can see the two crew members in the water after being thrown out. Note that the engine continued to run because they were not wearing a kill cord. The second picture shows two other RIBs who came to help and eventually managed to get a man aboard the run-away RIB who was able to take control.

In a single engine powered RIB with cable steering; if you fall overboard the wheel (helm) will quickly turn full lock - generally that is to the right (starboard), without you holding it. This is because under the influence of the clockwise rotating propeller, the helm is more stable at full lock clockwise.

In a boat with twin engines and contra rotating propellers, the same thing can still happen. Though it is slightly lest likely as the propeller rotation is balanced, each turning in opposite directions. Also if you have hydraulic steering the helm is more stable and more likely to stay set on the same heading.


The ‘kill cord’is a very important safety item on any outboard powered boat, which is critical to its safe operation. Most modern outboards incorporate an emergency engine stop switch or button, which disables the engine’s ignition system when the ‘clip’o n one end of the ‘kill cord’la nyard is pulled out. The other end of the ‘kill cord’ is designed to be attached securely to the cox’s leg or lifejacket. However, do not be tempted to fix it to your wrist, as it is likely to get caught when operating the boat’s controls and especially the steering wheel.

Please note, do not be tempted to buy a cheap ‘kill cord’la nyard, they are generally more than £10 each. Buy the one specified by your engine manufacturer for two reasons. Firstly it will fit and work correctly, remember this is piece of safety equipment, and secondly cheap ‘copies’o ften do not have the structural ‘inner core’ which make it strong enough not to break when it is ‘yanked’f rom the throttle control box as you fall over board. Check carefully that the ‘kill cord’t hat you have has an ‘inner core’a nd is not simply a ‘red’p lastic curly cable which will most likely break in service. The result of which is a cox’n in the water and the engine potentially still running.

Do you have a spare engine ‘Kill cord’? If so where is it kept? If you went overboard with the only ‘kill cord’a ttached to you, how would any remaining crew restart the engine to rescue you? If you have a secondary ‘kill cord’, would the remaining crewmembers know exactly where it was and could they find and fit it quickly to affect your rescue? All this before they lost sight of your small dark head floating on a dark sea in the large waves which most probably exist at the time of the man over board incident. Remember this emergency situation is very unlikely to happen on a sunny day with a flat calm sea.

If you, as the cox’n became a man overboard, you may be unconscious in the water and need urgent assistance. Another good reason for always wearing a lifejacket with an automatic inflation system fitted. If the boat was heading down wind and into tide at the time, you could find that the disabled boat goes one way and the casualty with the primary ‘kill cord’n ow falling off their leg to the bottom of the sea, goes in the other direction.

The solution used by the oil rig support boats, is to fix a secondary ‘kill cord’ close to the kill switch, perhaps employing a tie wrap to secure it to the throttle control box cables or other suitably close location. Then in the event of the cox’n falling overboard with the primary ‘kill cord’, attached, the secondary would be instantly and more importantly, obviously available to simply fix into position to enable the engine to be started quickly by the remaining crew members. However, do not ever be tempted to be lazy and use the ‘handily placed’ secondary ‘kill cord’ to start the engine under normal circumstances.



Please note; in the picture above, this throttle control box has a diagram conveniently placed showing exactly how to fit the secondary ‘kill cord’. Imagine you are travelling downwind into tide, when you fall overboard and unknown to the rest of the crew; the secondary ‘kill cord’is hidden away in the dry box (assuming you even have a spare on board). So with a dead engine and no way of starting it, they and the boat drift away from you, who is left stranded in the water with the primary ‘kill cord’s lipping off your leg.

Remember, once you have recovered any man overboard casualty, you must re-fit the primary ‘kill cord’ (if it is still attached to the casualty - or the spare in the dry box, if you have one) to the ‘kill switch’a nd attach the other end to the cox’n again. Alternatively, if there are no more ‘kill cords’ (no spare and the primary has been lost) then simply disconnect the secondary ‘kill cord’f rom the control cables so that it can be attached to the cox’n. Consider, if the sea is so rough that you have lost one cox’n, you are quite likely to be in danger of repeating the event, so drive much more carefully and seek shelter at the earliest opportunity.

Tim Moxey
Boat Handling Instructor/Diver Cox’n Assessor
Seamanship Co-ordinator, BSAC Eastern Region