Reply With QuoteWOW I may sound like a total idiot here, as said b-4 all I have ever owned is the past were prop boats. POP's you just went totally over my pea brained sized head!
a pump is designated axial flow because the flow of water is straight along the shaft. in a panther/jacuzzi y-j, to visualize, think of a propeller in an enclosed case, discharging through a single volute to increase velocity. in industrial applications, this design of pump is used to move hundreds of thousands of gallons per minute, but at low pressure.
the term mixed flow is sometimes used in reference to both designs, for different reasons. regardless, the berk/amt/agg/etc. design is a single stage centrifugal design. with this type pump, water enters the suction side near the center (eye) of the impeller, and is centrifugally forced outward throught impeller vanes, converting energy into velocity energy. the bowl volute sections convert a large amount of this velocity energy into pressure energy. the only limiting factors for this design are in maintaining an adequate water supply and structural design (strength) of the components; in other words, more hp will equate to more flow at higher pressure/velocity. in the axial flow design, a high enough difference between suction and discharge pressure will achieve shutoff head - no matter what the hp is, if discharge pressure becomes too high, the pump will not overcome it and flow is substantially reduced.
there are many different types and designs of centrifugal pumps. in an industrial use, the berk design is exactly the same as a pressurized water reactor's reactor coolant pumps, although an RCP is significantly larger. pump suction and discharge lines are 40", with discharge pressures in the neighborhood of 2200psi. each commercial pwr utilizes four of these pumps that are normally operated 24 hours a day for 20 months (if they are shutdown, the reactor must be shutdown).
simply, since force (thrust) = mass x velocity, the berk type design is preferable in hipo applications because it will flow as much mass as is needed, while continuing to increase pressure/velocity. through the efforts of many people over the years, this design in jetboat applications has continued to be refined for both performance and efficiency.
this is not to say that in the application you are looking at, the boat won't perform to satisfy your stated goals. but, to go beyond that for a higher performance objective, the axial flow pump will be the limiter.
