diff --git a/gtsam_unstable/slam/Mechanization_bRn2.cpp b/gtsam_unstable/slam/Mechanization_bRn2.cpp
index d2dd02dd3..0f3f2feae 100644
--- a/gtsam_unstable/slam/Mechanization_bRn2.cpp
+++ b/gtsam_unstable/slam/Mechanization_bRn2.cpp
@@ -101,7 +101,7 @@ Mechanization_bRn2 Mechanization_bRn2::integrate(const Vector3& u,
 
   // convert to navigation frame
   Rot3 nRb = bRn_.inverse();
-  Vector3 n_omega_bn = (nRb*b_omega_bn).vector();
+  Vector3 n_omega_bn = nRb*b_omega_bn;
 
   // integrate bRn using exponential map, assuming constant over dt
   Rot3 delta_nRn = Rot3::Rodrigues(n_omega_bn*dt);
diff --git a/gtsam_unstable/slam/Mechanization_bRn2.h b/gtsam_unstable/slam/Mechanization_bRn2.h
index fa33ce5b9..4c85614d4 100644
--- a/gtsam_unstable/slam/Mechanization_bRn2.h
+++ b/gtsam_unstable/slam/Mechanization_bRn2.h
@@ -42,7 +42,7 @@ public:
   /// gravity in the body frame
   Vector3 b_g(double g_e) const {
     Vector3 n_g(0, 0, g_e);
-    return (bRn_ * n_g).vector();
+    return bRn_ * n_g;
   }
 
   const Rot3& bRn() const {return bRn_; }