diff --git a/gtsam/slam/slam.i b/gtsam/slam/slam.i
index 52c1e13b2..8b64896f8 100644
--- a/gtsam/slam/slam.i
+++ b/gtsam/slam/slam.i
@@ -322,7 +322,15 @@ template <T = {gtsam::Point2, gtsam::Rot2, gtsam::Pose2, gtsam::Point3,
 virtual class KarcherMeanFactor : gtsam::NonlinearFactor {
   KarcherMeanFactor(const gtsam::KeyVector& keys);
 };
-const gtsam::Rot3 FindKarcherMean<gtsam::Rot3>(const std::vector<gtsam::Rot3>& rotations);
+  
+class Rot3Vector {
+  Rot3Vector();
+
+  // structure specific methods
+  gtsam::Rot3 at(size_t i) const;
+  void push_back(const gtsam::Rot3& R);
+};
+const gtsam::Rot3 FindKarcherMean<gtsam::Rot3>(const Rot3Vector& rotations);
 
 #include <gtsam/slam/FrobeniusFactor.h>
 gtsam::noiseModel::Isotropic* ConvertNoiseModel(gtsam::noiseModel::Base* model,