I had a brief love affair with a jet boat, years ago. I'm picking up a new hull and was thinking of installing a pump, Dom 12S. Set back? Why, just for more room in the boat or is there a performance gain? Is the plate and shoe going to do any good with a 500 hp +- power plant, or are they just for big motors. Would a loader be any better than the shoe? I would put a droop and diverter on it, is this where the plate would make more sense?  Thank you for your informative responses.

I had a brief love affair with a jet boat, years ago. I'm picking up a new hull and was thinking of installing a pump, Dom 12S. Set back? Why, just for more room in the boat or is there a performance gain? Is the plate and shoe going to do any good with a 500 hp +- power plant, or are they just for big motors. Would a loader be any better than the shoe? I would put a droop and diverter on it, is this where the plate would make more sense?  Thank you for your informative responses.

Which hull? Not all hulls need/want a set back pump. Is/was this an outboard hull? I/O hull? A brand new never-been-cut hull? A ride plate definitly makes a difference, and running a shoe gives you more adjustability on loading the pump, along with a loader. Diverter is a must for lake drivability, but a droop depends on hull, may need it, may not, too many variables, and more info needed.

Dan'l

I have seen many 21' s with an 'E' pump, similar to a setback...Starting fresh, I'd go with a setback, mill the intake for a shoe and ride plate, and run the 500 hp motor, and go have fun (sounds easy, right?)
On my 21', the ride plate and shoe were already on it when I got it, so I don't know how it handled before. I'm in the low to mid 50's with 450+/- hp., ("AA' American Turbine Impeller @ 48-4900 r's.)
1400 lbs easily doubles lake ready. Mines @ 2800+ lbs.

Hope this helps

Dan'l

   The same boat was tested by hot boat back in the day. It was running in the mid 60's with a small block alpha drive. Sure would be embracing to have 500 ponies and only hit 50 ish.

Thrust Vs. Weight

SBC & an Alpha prolly run 60's all day on the lake. But I boat on the river. 

Dan'l