Besides the strainer plate at the sea chest(as mentioned by smckennz) which is also required by the 2004 ABS rules, it is standard practice to install one more full size cleanable filter before the pumps
There are Reversing engines and non reversing engines coupled with reversing systems e.g.Reversing Gears, Controllable Pitch Propellers e.t.c
Can you give us an example of a Lost Motion Revercing System?