When deciding what to include in your grab bags contents - consider what items are packed already inside the life raft. Typically the following items are included:
If any of the above are not packed in your life raft, add them to the contents of your grab bag.
The life raft may only contain two parachute flares and two hand held flares. In the days before EPIRBs, VHF, and VHF DSC, flares would have been the main means of alerting the attention of potential rescuers - when such a small selection of flares may have been insufficient to attract the attention of other mariners who might not be looking in the right direction when each flare was ignited. Even today, it makes sense to carry additional flares in your grab bag.
The grab bag containing the above items may consist one or more water tight rigid containers or a waterproof kit bag. The location of the grab bag(s) should be known to all crew, and it must be accessible (i.e. not out of sight in a locker or buried under a pile of gear up in the forepeak).
Thermal protective aids are simple all in one suites intended to be worn on top of the wearers normal sailing garments, and are designed to help reduce the risk of hypothermia. Suits of this type are inexpensive and take up very little room in the grab bag.
A more costly option, as used by serious racers, are full dry suit style immersion suits. Having tried some of these out in wintertime in UK waters there is no doubt that these suits will dramatically increase your survival time. Companies such as Secumar have gone so far as designing suit as that can be worn discretely under as the wearers main item of clothing under waterproofs and lifejackets.
If the ship's EPIRB is not kept in the grab bag, make sure you take it into the life raft - so that you and not yacht wreckage will be found first.
How much water you need to take with you will depend upon whether any was contained in the packed life raft, and how long before rescue is anticipated. On an ocean passage it is a good idea to carry a five gallon jerry can of water near the life raft and/or carry a number of two litre bottles of water which can be readily transferred to the raft. Even when sailing coastwise, it is sensible to be able to take some water into the life raft - as sea sick crew may become quickly dehydrated.
The hand held GPS will be useful for providing a position to rescuers by VHF or mobile phone - particularly if the EPIRB isn't a model which transmits a lat long. It may also be useful if you can influence the drift of the life raft, or for assessing the proximity of land or shipping lanes.
The following items may be in frequent use onboard, but are useful items to transfer to transfer to the grab bags or life raft prior to abandoning the yacht.
The remaining items are not essential to survival, but have been found to be useful by 'survivors' following rescue or safe landfall.