I'm having the same problem but only when trying to simulate lots at the same time. Here's the model and some pics. When I have only one oar there's no problem but with all of them the program crashes. NOTE! In this model I didn't attach the jonts and motors to the model yet. [image: HWiS_Argooar2animated.png] [image: GItI_Argooar2animated1.png] Argo oar 2 animated.skp