[CaptT820]

There are several companies out there that produce on demand concrete and have trucks that only begin mixing the ingredients to produce concrete when they reach the job site. Not sure on truck weight or barge capability, but this may be an option. All the big concrete companies offer concrete mixes that involve a retarder of some sort to allow the mix a longer hold time so it doesnt set up before it reaches the job, this is probably a good option for an island. Best days to order a concrete truck for this type of project would be when the weather is cloudy and the temperature is between 55 and 70.