I am questing for something thaat may not exist:

1)A sturdy weatherproof box, ten cubic feet or more in capacity, that will hold survival supplies (water, food, FAK, commo items) for long term storage
2)When opened, would automatically signal the event to responsible agencies, who could then investigate the incident.

Several of these would potentially be placed at various locations on Santa Rosa Island, California (one of the islands within Channel Islands National Park). I have worked for the NPS within the park for many years, beginning in 1982, doing both archaeological and paleontological field work. Originally a working cattle ranch with fairly easy vehicle access across the island, the island is now a proposed wilderness area, with a steadily shrinking road network. This is good overall for park values, but it creates challenges for researchers and park managers.

One change is to approach areas of interest from the sea and land on the beach, an often tricky operation with its own set of problems, many of which could leave a party stranded inadvertently on the island.

Hence the thought about prepositioned survival caches. These would be potentially useful for many others as well, like shipwrecked sailors, etc. Automatic notification seems desirable, because there is a decent chance that a survival cache will be vandalized or used inappropriately. Hence, automatic notification.

Your imput is greatly appreciated.

A steel job site tool box is about the right size — you might be able to rig an automatic radio alert upon opening one. They’d need regular maintenance.

Are the islands covered by local cell service?

It would be fairly easy to rig a EPIRB to go off when a weather proof box is opened. You'd just modify the system that sets it off when the ship sinks and it floats away. The steel job site variety previously mentioned are fairly water tight.

Cell service is at best spotty, and realistically, non-existent. On Santa Rosa Island, there are plenty of places where the park's radio net doesn't work. You are not able to trigger a repeater...

You are also dealing with variables like sea conditions and visibility (fog) which can change very quickly. Just because you can talk to the mainland doesn't mean you can reach the mainland.

Thereis an airstrip an dock on the developed portion of the island, but you can easily be a long day's walk (19-20 miles) distant.

If you are on the distant portions of the island, you need to have plans in case you have to spend the night out. This is one of the things that make working on the islnds so intriguing - you are close to civilizaation, yet very distant.

What is the nature of the mod? Sounds interesting.

If the island is so dangerous that you need to provide survival caches for people, why not implement a permit system? Nobody is allowed to go there without an advance permit that details their plans, and informs them about resources on the island. For survival caches to work, you'd need to pre-inform people about their existence and locations in the first place. So just replace that pre-inform step with a permit system.

For people who would ignore the permit system, then they would be on their own, as they should be.

For "normal" visitors, there is an already existing permit system, much as you describe, and ti has been working rather well. The people who venture into the far reaches of Santa Rosa Island are well informed and equipped.

My concerns are more immediate- my own body and those of colleagues. With the demise and decay of the rod system, the more practical alternative to accessing the regions of interest is beach landing via skiffs, often on the far end of the island, easily at least a good day's hike (18 miles) from the developed area.

Dealing with skiffs in the surf, you want to be nimble, quick, and lightly loaded. Part of your load is necessary gear to record and deal with the material you encounter - not a whole lot left over for dealing with emergencies. Emergencies, while not routine, do occur from time to time, altering the plans of staff working remotely. Historically, shipwrecked boat crews have wound up on the beach.

Sometime in the 1940's,a group of poachers flew to the island, landed, shot their elk, and then found they couldn't take off, having to walk a considerable distance to the ranch and ask for assistance. They got off the island, but their plane remains where they landed. they were treate generously, if you ask me.

Prospecting for paleontological material will be continuing operation, long after I am inactive. Workers stuck on the island will need water, food, and some sort of shelter. While the climate is mild, high winds are routine, and hypothermia is possible. A decent survival stash could be very handy.

I am trying to plan for the eventually inevitable mishap and have necessary items available.

Thank you very much for your comments. I have enjoyed working in the park (it is quite a remarkable place), but accidents do happen...

Sounds like a steel shipping container, would work. Shelter and storage in one unit ,could be dug in to a hill side or sand dune .MTC

If this cache is for your workers, then do you need to have it accessible by the general public? Lock it up tighter than a drum in heavy duty containers with hard-core locks that only your workers have keys for. Inside that container keep a maritime radio, a reasonable portable antenna, and solar recharging gear for the battery. All inside a convenient day pack. Include instructions on radio use if your workers are not familiar with that. Also, a map to the top of the nearest high hill if the route to the top is difficult. Sure, you'd have to be able to hike to the top of the hill to use the radio effectively, and you might have to wait a day while dead batteries recharge via the solar, but from up high I'd think you could probably get the 20-30 miles (???) to the mainland or to a passing ship. You might not have a long transmit time with weak/discharged batteries, but you could hopefully at least get an SOS out before they died again after a partial solar recharge.