Mostly my experiences with the bad programs were on cookie cutter OSV’s. An OSV company that I worked for was notorious for building 6-10 vessels from the same design but each one was slightly different than the previous. Then the company would only pay for 1 set of drawings, schematics, stability program etc. To make it even worse the 10 boats would go work for 10 different clients all over the world doing completely different jobs. Some would be turned into fraq boats, others strictly mud & others would have the mud tanks converted to fuel tanks. With that company captains, mates & some engineers would just do bullshit stability in their heads. The programs were useless in many cases & guys went by the principals to never sink the marks, don’t put to much weight too high, don’t run with slack tanks, don’t sag, don’t hog & pray as much as possible. In hindsight I’m surprised more vessels didn’t sink or flip over.
The times I’ve timed the rolls or checked because of wind heel never found an error. In my experience all the various errors that were missed (wrong data entered etc.) were discovered because of discrepancies between calculated and actual drafts.
I did some time on a supply boat as AB, after getting out of the Coast Guard and going through SUNY on vacations and such. On one trip me carried containers 3 high on the work deck from Florida to the Bahamas. On the bridge there was a placard saying no load on the deck over 6 ft or something like that. Didn’t say anything - but was happy when they were off.
Do you mean “feel” as in “this boat/ship feels loaded wrong” or feel as in you can decide in your head how to load better than the official calculations would tell you.
Any decent seaman with time on the boat should be able to feel when something is wrong, but the second case seems like someone needs to redo the assumptions behind the loading program so it works correctly instead of doing it in your head.
Not to dumb this stuff up. Not a ship guy, but on Large tugs and tow stuff, we “had a feel” when shit wasn’t right regarding boat response in weather on vessels we were familiar with. Valour (Sand Pebble) )did have a permanent list, my chief compensated for that , had no problems. Sailed other Houma built sister rigs that were awesome. Handled quite well. Agree totally you have to know the vessel, but not always possible. Most of my engineers were spot on. I always wanted to run balls to the wall with EMD;s , My last few chiefs requested 880, not 900 rpm. , Glad I listened to them. Wish I could shake the hands of the respectfully departed for getting the crew home in one piece. They ballasted my numerous rigs quite well, and understood stability, Feel of the vessel does come into play. . The ride mattered. We had coffee chats most mornings, I do miss that. Kept us safe no matter what the weather.
My previous comments of course realizes that the “normal” avenues of strength and stability calcs have been verified and that some resemblance of normalcy exists…Do remember though (and I have found this aboard at least one vessel that I was asked to review the strength and stability printouts) that all of these stability programs are dependent upon correct initial input- and also later as the conditions change… I found one program printout to be WAY off the mark, probably by bad data input.
Another thing that is routinely overlooked is that the minimum GM varies widely by changes in the vessel’s displacement- a sliding scale if you will… These things therefore make it of extreme importance that we recognize changes in the vessel’s movement, not only roll period- but also sluggishness, higher power to maintain speed- hell, I could tell the difference on one ship (an MSC UNREP Tanker) when we started get slack in the forward wing cargo tanks (#2 & 3 P/S Wings) after and unrep…
The Bourbon Dolphin went to work with a nonfunctional stability computer and serious discrepancies in the stability calculations (mass of uprated tow winches unaccounted for). As it played out, no amount of feel could save them, because the event that precipitated the capsize (dropping a pin) was instantaneous and irreversible.
The ex-CG vessel that has spawned most of my sea stories didn’t have a stability booklet. The Man didn’t know what it was, and shrugged when I explained matters. I have already posted pictures of the inclinometer maximum needles off the scale at 55 degrees port / 60 degrees starboard. Did that cause me to “have a feeling”? Oh yeah. Did it help? Not at all, because The Man had different feelings, so to speak. It really made me wish for an inclination experiment and fresh calculations, but I lacked the political clout to make it happen. Nobody died, so it might be a poor example.
However, iffy stability feel has saved me, or at least instituted new operational parameters. For example, there was a privately constructed motor yacht that gave me the absolute creeps the first time we encountered beam seas with the athwartship fresh water bunker slack. After that we simply made sure that the tank in question was pressed up whenever we put to sea, and lived happily ever after.
Of course “feel” matters wrt stability, and learning to trust our instincts is an important effect of gaining operational experience. As @Kennebec_Captain points out, the key is to reconcile your sixth sense with concrete aspects of the ship’s condition, either figuring out what’s wrong or expanding your understanding of the ship’s behavior. Only the shoddiest kind of terminal 3M would ignore a feeling that something is seriously wrong and rest easy knowing that the numbers look good.
My answer is similar to yours wrt the question about the gear box lube oil levels.
With the gear box the rule of thumb is follow the manual and if someone is not doing that ask they why. There are two possible reasons; either they are stupid and/or lazy or they have solid explanation as to why the manual can be disregarded in this instance.
Stability on the car ship can be a bit complicated so our rule of thumb is use the stability software but maintain a margin of safety in case of errors. If those rules are not followed (for example changes well within the margin of error) there should be a solid and knowledgeable explanation.
One of the things I developed a hatred for very quick in my maritime engineering career was when the bridge would call down & ask for me to level the vessel, usually with a set of designated midship wingtanks used for the purpose of leveling. Why I hated it is because more often than not, as soon as the last valve was closed & I’d get back to the ECR the phone would ring & it would be a capt or mate saying it still looks 1/2 a degree or less off & they wanted us to turn the pump back on for a couple of minutes. That “tad-bit” leveling is mostly decided by feel in my opinion. I now tell them, “Its really hard to tell when we are level down here because we don’t have the horizon to judge by & our inclinometer is warped so please call when you see us level & we’ll shut the pump off & close the valves.”
If I gave the ship a 8 degree list then called the bridge & said we were level in the engine room that would be equivalent to filling a gear box slap full & calling it normal.
Yeah, on the car ships typically the engineers don’t get involved with pumping ballast. We had two ballast control rooms, one in an office in the house and one down on the main (6-)deck.
Cargo ops sometimes involve a lot of pumping. For example shifting the side ramp from the main deck to the lower deck involves first listing towards the pier to keep the ramp angle low then after shifting listing away to keep adequate clearance under the ramp.
On a drillship you have to keep her reasonably flat or the drill pipe will rub against the low side of the RKB ( Rotary Kelly Bearing).
As fuel is burned, drill mud pumped down hole, and water and groceries are consumed, ballast water must make up the difference to keep displacement the same.
There is not a lot you can do about the fore and aft bubble.
One thing I noticed early on as an AB some captains and/ or mates when towing in weather would call for port or starboard ballast when the barge most usually turned into the weather resulting in a list due to tow wire pressure. When it started following us, the list went in opposite directions. A properly ballasted boat IMHO should be left alone was my lesson. A heavy bow or stern would be addressed in those conditions, but not side to side.
The vessel that I worked the longest on that scared me the most concerning stability was a fraq boat. None of the clients tanks, which were above the waterline BTW, were center ship, all were port or stbd. They would use humungous pumps to pump thousands of barrels of fraqing chemicals at thousands of psi through their coflex down the well in 30-60 mins. Both of our ballast pumps working together couldn’t keep up with the amount of chemicals they could pump. So we had to start the high pressure down well sequence with a wicked list, start correcting with our ballast pumps & have an equally opposite wicked list 30-60 minutes later once all of their product was off the vessel. Master, CE, 1A/E, Chief Mate & anyone with enough sense to know what could happen if something went wrong were awake during that step of the job. Fraq boats don’t feel right IMO.
I hate it when we are in port & a capt or mate wants to level the vessel against the wind. Every increase or decrease of 10knts & they want to fight it. I’ve been lucky in the last few years to not work with a bunch of guys worried about every gust that blows.
Yes, you have been lucky. At the dock? Good grief. Subject is how important is “Feel”. I noticed the bow was digging in a 7-10 ft head sea and not recovering as well on a tow wire. Called the chief and asked is all your shit right? He said yes, let me look around. He went up to the galley to see water dripping into the quarters while some crew glued to the TV/videos. Come to find out the rather large forward hatch was not secured and water filling the forepeak. Talk about feel for the vessel, it’s real. No computation neccessary in this case.
I don’t know anything about this type of work, don’t know what a Fraq boat is.
I also don’t know what the crew of theses boats have available to them wrt stability.
All that said, this might be a case where digging into a bit of theory, in particular the righting arm at deck edge immersion might be worthwhile.
Teaching has come along way from using a piece of chalk. I remember Swires having a heart stopping simulation video of anchor handler stability with weight on the towline in heavy weather.
I sailed with captains who had taken the long road to reach their present position starting with sailing on short sea vessels of 500 ton max. Most ships were 499 tons. Often the North Sea weather was foul and treacherous. The only navigational instruments in those days were a compass and a radio direction finder. That was a tough learning curve. They learned to live with all kinds of sea and wind conditions. Gradually they developed a sense of total situational awareness which was necessary to survive.
One captain said that the ship was not the problem as he knew all the ins and outs but it is necessary to develop at all times a sound perception of the surroundings as this is essential for safe sailing. Situational awareness according to him is the key to success or failure.
The same captain said something interesting. The feel for the sea and the ship by Mariners is inversely proportional to the height of the bridge above the sea. At a bridge height of 40 meters the waves do not look that high and mighty and this can be a reason that the ship’s speed is kept too high for the prevailing weather conditions, to press on, which can cause damage and also loss of containers. With a bridge of only 10 - 12 meters above the sea level it is another world down there.
It doesn’t get any more honest than that. I would like to add that perhaps higher the altitude from sea level, lower the surrounding air pressure that might cause people on larger ships to have swollen heads.
There is definitely something to that. I’ve noticed a a difference between third mates that have sailed on tugs and the ones that haven’t.
For example on some of the car ships there is a flag halyard aft of the house on the center line. After leaving port and coming up to sea speed that halyard clip sometimes starts banging, same rhythmic bang-bang-bang you sometimes hear in marina where the clip is banging on the mast of a sailboat in the wind.
I can hear it from my office while I’m doing the departure messages.
Sometimes the banging stops after a few minutes, that mate likely sailed on tugs. The fix is to just go outside and hoist the clip clear of the bulkhead.
More often I end up going up to the wheel house and I ask the mate; “What’s that banging noise?”. If I get the answer “Don’t know, I was wondering the same thing” then no tug experience.
Some new third mates assume that if it involves stepping outside and having a look around then it’s beyond their purview.