if i set this

"TimerRepeat": {
"spawn cargoshiptest 250,0,4500": 3605,
"spawn cargoshiptest 250,0,4500": 3695,
"spawn cargoshiptest 250,0,4500": 3785
}
}

the first ship comes, but not 90 seconds later the second ship and after the third ship, why?

I don't think it works the way you want it to.

Use Timer Once for what you want to accomplish. Im not sure if cargoshiptest accepts arguments for the spawn position though.