Can you run the main engine submerged while still on the dry dock?

Might be a stupid question, but has there been any instance of fully running the engine and propellers while the boat is seated on a drydock partially submerged in water (still grounded to check if the shaft are free from vibration)? My first impression is that this is dangerous and should not be attempted but, maybe you guys have experienced this before.

Engines are two CAT 3152C 1194BKW

 

If you run the engines at full power in those conditions, the propellers will cavitate and probably ventilate too. This will cause vibration. However, if it is only to check if the transmission is shifting, then it can be OK.

 

I agree, we did not went ahead with it. We just launched the vessel as normal.

 

Normally, you keep the boat in slings for minor system checks. That way, if something is wrong, you can pull it right back out.