We will have job this coming week and gona be the first time in our company to do this, Its a sea wall 300 yards of 5000 psi.with fiber concrete.They're discussing what is the best thing to do load the pump and the concrete trucks in the barge or we gonna do a line which is 1000plus feet long its a flat terrain.In my opinion if the barge can load the 30 concrete trucks of 10 yards each so be it,

My question is will  boom pumps can push that 5000 psi concrete in 1000feet line??.

5000 psi is equal to 35 mpa wich means a B35 mix in my book. And 1000 + feet is 300 + meters.
Have done it with 5" line and B45 concrete with 32 mm agg. and it worked fine, but that was 200 mm slump, so I bet higher than you are gonna use and I had no fiber.
And if you have a failure or a simple plug somewhere you will have a hell of a job to clear it and start up again.
Would have a backup pump just in cause.

And if you load them all up on one barge they are all gonna sit there and cook, so when you are halfway through the rest of the trucks will be unpumpable.
Did it once with underwater mud and 3 trucks on a barge, took 8 hours before we got to the last truck and ended up with a good ol' boom party and had to drill out the lines...
Remember you are out on the sea and far from help.

If possible I would use 2 barges, one with the pump and a couple of trucks out and ferry the rest out with the second.

Lots of retarder or ad water in the mixers on the barge , load some tanks with freshwater...

i have pump through 750 ft of 5 inch line at a 160 slump with fiber and i didnt have any problems

you mean you use boom pumps? were planning to use our putz 36m, if possible gotta be no mess were working on a resorts wherein a lot of guests, minimize noise etc..good thing for the line is we gonna control the truck interval.

1000 ft. is nothing i have done that with a 900 schwing or an old 12 cell putz. My concern can the contractor move the material into the wall fast enough. Is the contractor going to jerk around turning the pump on and off  good luck

I notice you live where it gets alittle hot out. I have in some situations put sprinkler hoses on the pipe line to keep it cooler fro the sun beating on it. make sure your wear parts and cups are in good shape