Hobie,
Sadly, that seems to be the case with the centrifugal pump used on those jet lower units. There are some axial flow units that doesn't waste efficiency by making water make that 90 degree turn coming up into the pump and then being directed aft for drive.
There is no reason that a well designed and properly mounted prop-guard can greatly add to the safety of a rescue and/or training motorvessel. The plastic Prop-Guards mentioned earlier have a cast aluminum version called the MPT that we will be using on a Waikiki Beach daycharter catamaran. The...