If you're talking about sims two castaway then here's the answer. You send SOS by finding the radioin island1 and transmitter on island 2, and when you get on island 3 go on the volcano and put the radio down on top of it and then choose to put the transmitter on, then once you have it on choose to send SOS. Or you don't have to send SOS at all just build a big seaworthy boat which you find the directions to make down the diving thing in island3. In my opinion, sending SOS is way easier than finding all the materials to build the ship.
The volCanoe summit
you have to get the radio(found on the 2nd island in the airplane jungle) and the trasmiter(found in the river jungle) then you go to the sumit of the volcano on the third island and put them togather and send the SOS
the cristal island is full of cristal and you can send a SOS and some alients will cam and give you alient food
You can either send a SOS from the top of the volcano on the third island, or you can build a boat at the north volcano beach. :)
To make an SOS you: First get the radio from Airplane Jungle on the second island. Then you get the transmittor in the south river jungle also on the second island. Then you take those two things up to the third island up to the Volcano summit. You then place the radio on the ground somewhere and an option will say "Repair radio". Then you can send an SOS You can't make your sims be completely naked. There will be blurry bars or they will be in their underwear.
i just posted it. you build a sea worthy boat or send an SOS with the radio and antenna from the top of the volcano
Collect both parts of the wrecked plane and get to the top of the vulcano. If its right you can send the SOS
sos
When they are in distress.
find second island ( Airplane Jungle ) there is a radio. So you must find transmitter in this island. You can send SOS in Third Island in Volcano Island
You go to Crystal Island and send a SOS with the airplane radio (plane jungle, island 2) and the antenna (other part of the plane jungle island 2).
Not all dungeons let u send an SOS messeage although most do ~James~