I have recently been asked to help get an old tug through Sub M inspection. It’s the first one to be inspected in this company and maybe the second for the local CG.
The local CG questioned stability when the vessel was floated out of dry dock with a 5 degree list. No ballast on board and so fuel was transferred to correct the list. The day tank is on stb and has always been balanced by ballast or potable water. They said the vessel must sit at exactly 0 degree list with fuel tanks pressed full and other tanks dry(quoting stability test requirments). Even though we can prove a safe operational history they are not comfortable with the way the reg’s are written and they are looking for a way to avoid passing us on the stability issue without some mathematical backup to cover there decision in the event of an accident. But what good does it really accomplish when all they can require(after list is corrected) is an operational test where they ride along and “ determine” wether they feel the boat is stable or not? A slack tank isnt going to affect the feel of the boat so it should have no effect on their determination after going for a spin in the harbor.
I understand the issues old, modified vessels( lighter engines, upper pilot house) can have with stability and so 3 years ago I asked the CG how they were going to address stability testing with Sub M and they said clearly that existing vessels would only have to prove their safe operational history and would not be required to complete the full stability test process.
144.300 Stability standards for an existing vessel.
(a) The owner or managing operator of an existing vessel operating under a stability document must be able to readily produce a copy of such document.
(b) The owner or managing operator of an existing vessel not operating under a stability document must be able to show at least one of the following:
(1) The vessel’s operation or a history of satisfactory service does not cause the stability of the vessel to be questioned by either the Coast Guard or a TPO engaged to perform an audit or survey.
(2) The vessel performs successfully on operational tests to determine whether the vessel has adequate stability and handling characteristics.
(3) The vessel has a satisfactory stability assessment by means of giving due consideration to each item that impacts a vessel’s stability characteristics which include, but are not limited to, the form, arrangement, construction, number of decks, route, and operating restrictions of