Starter Battery Ground Point

I am installing LifePO4 batteries in a boat replacing wet cell batteries. The question is the starter battery ground. I am using a Victron Smart shunt. My thoughts are that the starter ground should go to the negative buss bar (connected to buss bar that is also connect to LiePO4 ground) which is essentially the same potential as the battery minus of the shunt.

This diagram includes the correct placement of starter battery and ground.

The starter is not a load that I want the shunt to measure. The starter battery will start the engine and the house bank will not contribute nor be affected. What would be the outcome be if the engine block and starter ground are on the same buss as the house negative? I viewed that wiring schematic previosly. Thanks for your response.

The starter battery often (but not always) has a common negative with the house battery. The drawing shows where that common negative is connected. The SmartShunt will not measure the starter current.

If the starter negative, house negative (via the SmartShunt), and ground are on the same bus nothing untoward will happen, the bow thruster negative can also be on there. Mine works fine as shown, SmartShunt only measures house loads.