The sailboat we are buying has two SOSpender life jackets (PFD) with pull cords to inflate. There is also one that will automatically deploy if the wearer falls in the water. Are these a good idea? It would seem to me that they are comfortable but, if you are hit in the head with a boom, pretty usesless unless you are wearing the auto version. How can you pull a rip cord if you are unconscious? They are certainly expensive and comfy but......what are your thoughts. What you you wear instead if you do not thing these are good? Thanks