I was doing some maintenance on the boat yesterday and checked my oil level. The oil was well below the minimum mark. Only the tip of the dipstick had oil on it. I don't remember when I last checked the oil level however the last oil change was on 9/7/2017. I put 200 hours on the engine since that time. Engine performed normal the whole time. I do have a oil pressure gauge that never went off. Engine is a Volvo 63P-A with about 5200 hrs. Should I be concerned?