Start an editor session
Place a boat rack, oriented as desired, named myboatrack
Place a player near the boat rack
Start multiplayer session (single player not tested)

Issue the console command

mydetectors = allMissionObjects "emptydetector" select { getposasl _x distance2D getposasl player < 100 };

Issue the command and note that there are two detectors

count mydetectors;

Issue the command to record their positions

mypositions = mydetectors apply { getposasl _x };

Issue the command and note that the boat rack rotates 90 degrees

myboatrack setdir (getdir myboatrack + 90);

Issue the commands and note that there are still two detectors

mydetectors = allMissionObjects "emptydetector" select { getposasl _x distance2D getposasl player < 100 };
count mydetectors;

Issue the commands and note that the detectors have not moved

mydistances = [];
{ mydistances pushback (getposasl _x distance (mypositions select _forEachindex)) } forEach mydetectors;
mydistances

Issue the command to delete the boat rack

deleteVehicle myboatrack;

Issue the commands and note that there are still two detectors

mydetectors = allMissionObjects "emptydetector" select { getposasl _x distance2D getposasl player< 100 };
count mydetectors;

This prevents the use of spawned boat racks during a session, which we do for our operations. It can be worked around by locating and moving the detectors manually.