If the boat is brand new, there is a fair chance you have an obstruction from construction debris that was not adequately cleaned from the tanks. More than likely it is clogging the inlet at the pump. Alternatively, the hose clamps may need to be snugged so the pump won't draw air.
Another possibility is that the air leak or blockage is at the manifold, which might explain why switching tanks had no effect and your "back-up" pump also did not work. It's difficult to say for sure without seeing a water system schematic. Is your back-up pump a foot-pump?
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Pacific Seacraft Crealock 31 #62
NEVER CALLS CRUISINGDAD BACK....CAN"T TAKE THE ACCENT