Took boat out Sunday , cruizing about 3000rpm and notice oil pressure dropped to 0 so i shut off motor and noticed my oil line to the cooler came off, It dumped about 5 quarts into bilge. No oil on dip stick so i added 3 quarts of oil started it back up, it had normal oil pressure and seem to run fine. Any damage ???

Drain the oil and check for any materials. If there is debri in the oil then some of the bearings ran dry. But you didn't state the amount of time it was running at 0 oil pressure?? If there is debri which from the sounds of it you may have caught it in time. I would do a tear down and inspect everything at least the mains and Rods at a minimum. I was running 10lbs for about every 1k rpm. Which is perfectly normal for some engine builders. I didn't like the 10lbs. Did a tear down and found brass on all mains. It was extremely close to spinning a main.

I lost an oil filter at 5000RPM and ran until I noticed the red light on the dash.
Did an oil change ran for another 3yrs without any problems. I did cut the next couple of filters
open and inspected them.

Dont think it was very long , i always keep a eye on it.

Just curious, what oil lines/fittings are you using?

Update, changed oil and filter , I now have good oil pressure and it runs fine

I had a similar issue where the pressure sending unit brass pipe cracked off and pumped all the oil in to the bilge. I might have had less than a minute on it. I filled it with oil and ran it for a few more weeks till the end of the season. Pulled the motor to change the bearings and saw nothing wrong with the bearings. Still changed them though. I would think you would be OK if you caught it fairly quickly.