diff --git a/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/constraints/sixDoFRigidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.C b/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/constraints/sixDoFRigidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.C
index 1bd6f0a850..62e01cf435 100644
--- a/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/constraints/sixDoFRigidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.C
+++ b/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/constraints/sixDoFRigidBodyMotionConstraint/sixDoFRigidBodyMotionConstraint.C
@@ -60,7 +60,7 @@ bool Foam::sixDoFRigidBodyMotionConstraint::read
     const dictionary& sDoFRBMCDict
 )
 {
-    sDoFRBMCCoeffs_ = sDoFRBMCDict.subOrEmptyDict(type() + "Coeffs");
+    sDoFRBMCCoeffs_ = sDoFRBMCDict.subDict(type() + "Coeffs");
 
     return true;
 }
diff --git a/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/restraints/sixDoFRigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.C b/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/restraints/sixDoFRigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.C
index cd0a5b39d5..10ea658140 100644
--- a/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/restraints/sixDoFRigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.C
+++ b/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion/restraints/sixDoFRigidBodyMotionRestraint/sixDoFRigidBodyMotionRestraint.C
@@ -60,7 +60,7 @@ bool Foam::sixDoFRigidBodyMotionRestraint::read
     const dictionary& sDoFRBMRDict
 )
 {
-    sDoFRBMRCoeffs_ = sDoFRBMRDict.subOrEmptyDict(type() + "Coeffs");
+    sDoFRBMRCoeffs_ = sDoFRBMRDict;
 
     return true;
 }