If we''re talking a boat in the 30 foot plus range, then the loads on the rig are many, many times the 165 pound weight you''re talking about.
What you do have to consider is the range of movement......on a 30 foot mast the tip moves through about 15 feet at 15-20 degrees of heel....with a good puff this can happen in seconds. In other words, unless you are very firmly attached you are going to get slapped around something fierce....
So, the only way I would go up at sea is if a repairable equipment failure is becoming a safety issue, and then I would only do it in calm seas, with the boat stopped and as stable as possible under the conditions.
Oscar, c-42 "Lady Kay"