Maritime Wood

Type of Light.
The dedicated lifejacket lights had either fixed or flashing lights. There is plenty of debate about which is best. Some say that in a moderate seaway flashing lights catch your eye more, although in a big sea the flashes could correspond to the trough, and therefore be seen intermittently or not at al. To conform to SOLAS (Safety OF Life At Sea), flashing lights need to flash between 50 and 70 times per minute, so you’d need a very confused sea to hide them.

Fixed lights could easily become mixed up with the reflection of shore lights closer inshore. We found that it was not the light but the type of lens that could make the difference between being seen or not. The strobe lights were tremendously bright but trick the eye into thinking they move around a lot. Ironically, the normal lifejacket light could be seen from further away than the high intensity strobe lights.

Operation
All the lights were either automatic or manually operated. Automatic lights switch on in contact with water: Manual lights had a variety of ways to switch them on. The strobes tend to use knurled twist switches at the base or top of the light, whereas the lifejacket lights use pull-cord activation. For a lifejacket light we thought an automatic light would be most useful, but with the facility to turn it off in daylight.

Batteries,
Two types of batteries are used in lifejacket lights, lithium cells with a five year life and those which use a chemical reaction between the battery material and water. The latter will operate in both sea and fresh water. Lithium cells can generally be tested and switched on and off again, whereas the seawater- activated cells are for one-time use.

Construction
Under SOLAS rules, commercial lifejacket lights undergo a tough testing procedure in which their performance in varying temperatures and conditions is monitored. Most dedicated lifejacket lights comply with the SOLAS code. Try to buy those which conform to the latest tests. Personal survival lights do not have to comply with the code.

Round Up
Even if you are wearing a lifejacket with a dedicated light, you may still be invisible from just six boat lengths away. It all comes down to the angle of view for the rescuers. Lights are generally fixed to the lifejacket’s mouth inflation tube or a dedicated area just above it. We found this to be of little use in the water. The MOB’s head obscures the light and gives a 160° blind arc to the search vessel. It’s a shame that lifejackets are not designed to take lifejacket lights. If they were, there would be a raised part of the jacket to which the light could be fixed, giving 360° effectiveness. The costly alternative is to fit two lights, one on either side, or to have a lifejacket light and a personal light with a torch facility. If you fall overboard at night, shine the light at the boat or try to turn yourself around so the light is showing.

If you’re searching for a MOB, don’t give up if you can’t see the light. Hit the MOB button and start a search. The MOB’s light could be on, but in your blind sector. All of the lights tested will be highly visible to a search and rescue helicopter.