This is a MATE Compatible version of my ROV Kort Nozzle for Bilge Pump Thruster w/Integrated Mount.

The New Rules for 2018 state.. (courtesy of MATE)

3.2.5 Propellers
New in 2018!!!
MECH -006: Propellers must be shrouded and have thruster guards. ROVs that have propellers exposed without thruster guards will not pass the safety inspection and will not be allowed to compete. A shroud must completely encircle the propeller and extend at least 2 mm in front of and behind the propeller. Thruster guards must completely cover any openings on the thruster and should have a mesh size that meets IP-20 standards (solid particulate protection level 2). This IP code equates to a mesh size >12.5 mm. To pass safety inspection, the shroud and propeller guard should meet this standard. If your finger can touch the propeller, then it is not properly guarded. Teams may construct
thruster guards, 3D print thruster guards, or may purchase commercially available thruster guards. All motors on the ROV must be protected with shrouds and thruster guards.

These modifications should pass tech inspection according to the rules but I am NOT 100% sure of that so use at your own discretion.

There are two different versions...
Mate_Bilge_Kort_Thruster.STL I added more support arms to satisfy the 12.5 mm rule.
Mate_Bilge_Kort_Thruster_2.STL I added one more arm and is to be used with Mate Wire Gaurd.STL

The wire gaurd should be printed using at least 3 outer shells and 0 top and bottom layers with a honeycomb pattern infill to achieve the mesh. I used 7% infill to make an .11 mm mesh size. You can glue or tie the ends together in place on the thruster and it should stay in place.

The pro guards mount with (4) 2-56" flat head screws. I used 1/4" length ones but they do poke through the other side a bit so you might want to try slightly shorter ones.

I have only test printed the wire guards and Prop guards (as seen in the pictures) to test fitment. I have not tested the actual thrusters so I'm not sure if these modifications will affect performance.