The calculations done by the naval architect, not the crew’s
According to the Marine Safety Center, the hydrostatics model that the naval architect provided for the vessel "did not accurately represent the Scandies Rose, " for multiple reasons. MSC alleged that it did not accurately model poop deck or forecastle enclosed volume (top image), did not model the bulwarks, had significantly less superstructure windage than the actual vessel, appeared to have much different tank capacities than the vessel capacity plan, and neglected downflooding in calculations.
I’m torn. On the one hand I appreciate the effort the USCG is putting into investigating the loss of the Destination and the Scandies.
On the other hand the investigations seem to be repeatedly going off on tangents that either won’t lead to any effective regulation changes or are based on poor assumptions and understanding of the seamanship involved.
A lines plan from several decades ago is not going to match the profile of the vessel. Those things were not expected to match during that time period. The wave wall being altered isn’t going to affect reserve buoyancy.
I am getting really tired of seeing absurd operational lightweight changes in fishing vessel lightweight surveys. The boat didn’t gain 150 LT between surveys. An error was made and the error should be found and corrected. How a vessel passes a safety check with an unexplained 183 LT shift in operational lightweight in the stability booklet is unknown to me, but I’ve seen it again and again.
The symmetric 1.3/0.65-inch-thick icing required for stability criteria evaluation by 46 CFR 28.550 is obviously not a realistic description of icing and I’m tired of seeing that brought up like it’s some new revelation. Every stability booklet has a caution note about that and anyways it’s obvious. It’s an assumption to make the math work. Trying to model realistic ice formation would be impossible mathematically and given how quickly it can change wouldn’t be useful anyways.
These boats went down from slack tanks (in the Scandies case a void as well). Most likely a combination of slack tanks and an inability to correct the condition before the vessel capsized. I would like to see the USCG move away from weighing iced up crab pots and going ‘Gee, it’s heavy!’ and move toward requiring effective back up pumps and plumbing to voids and holds, effective alarms for pump failures and tank levels, and ensuring void and hold plumbing can be effectively backflushed in an emergency. That is a simple, easily enforceable change that will save lives.
This is certainly true. You would think after so many crab boat losses due to icing the USCG would convene a forum with crabbers to listen to them describe exactly how ice builds up on their boats (the patterns are always asymmetrical) and the thickness they actually encounter, then use this knowledge as a baseline for further recommendations. It shouldn’t be a matter of guesswork by a marine architect.
Another matter is the effect of icing on tank vents. Once those vents ice-up, transferring fuel or ballast to correct a list is likely not going to happen.
It has to be a matter of guesswork for a marine architect. Computer modeling of ice buildup and the associated stability changes is an impossibly complex task. The 1.3/0.65 standard is adequate for the purpose. It’s primarily a function of weight added for freeboard and GM purposes. Trying to make it more complex and realistic would just lead to dangerous assumptions. A little bit of knowledge is a dangerous thing.
Icing of vents is another reason to ensure you have proper backflush capability. Good to have a positive displacement pump around for that purpose as well. While it’s possible for a vent to ice up to the point where it won’t pop off with backflush pressure it’s exceedingly rare. Generally the ice will at least fracture to the point where the tank/void can then be emptied.
I am pretty much convinced the vast majority of crab boat skippers would not be able to comprehend the contents of his vessel’s stability book and likely has never even tried. Also they would not be able to rapidly effect damage control measures even if they had the piping systems and pumps installed. They are cowboys who catch crab without any true professional training or education yet alone holding licenses.
Every fisheries vessel over 79’ should have a loadline like any other commerical vessel, be inspected by the USCG like tugs are now and the master should hold a license commensurate with the tonnage of the vessel he commands. No more under 200ton exemptions. Hell make it any fishing vessel over 26’ just like for towing. Why not? The schools would rake it in!
Quite a few of them hold licenses and there are a number of boats in the fleet that are over 200 GT and require licensed personnel. What purpose would that serve? I sat for my 2000 Gross Ton Master UFIV upon Oceans a year ago. Do you know how many stability questions there were? 3. Out of hundreds of exam questions I had to answer, there were 3 stability questions and they did not relate to fishing vessel stability in the slightest. I can safely navigate Block Island Sound the way they did it 60 years ago though.
Your proposals to require loadlines and have every fisheries vessel be an inspected one is not only impossible, it’s silly and would reduce overall safety in the industry.
The skippers aren’t able to comprehend the stability books because the stability books are useless garbage. Relying on the contents of a stability book that incorporates a 183 ton shift without accounting for it’s origin will get you and your crew killed.
The amount of marine architects that are capable of producing an effective stability book for fishing vessels in the NW is dwindling quickly and there’s little interest in correcting that.
Until stability is approached in a manner that utilizes modern tools and can give effective information to the master this will continue.
As far as damage control, I’ll bet my last paycheck the majority of good fishermen can kick your ass at that any day of the week.
Be difficult to calculate stability in the dynamic situation of a fishing vessel working in adverse weather. A better way might be keeping track of the rolling period with a smartphone app or similar method. A clear warning while underway in icing conditions would help with crew decision making.
I’ve looked into that but the techs not really there yet. Bering Sea wave periods and smartphone acceloremeters don’t play well together. Would lead to alarm fatigue. A purpose built device might work better if the price can come down.
They do make pre departure checks easier and way more accurate. Especially when you’re fatigued and don’t really want to do it anyways.
I meant the smartphone tech. And actually, the tech is there just the interpretation of the signals that needs to improve.
Visual monitoring of icing works pretty good really, so you have a choice between working on monitoring stability better or working on monitoring tanks/void spaces better. In an ideal world both, but more progress can be made faster monitoring tanks and void spaces better. The tech is there and has been for decades, the requirements are weak and motivation is not always high. The focus on icing and stability is detrimental to what should be a total focus on seamanship.
Ice gets talked about a lot but the ice didn’t put these boats down. Ice loses you time and reserve buoyancy/stability when something else happens.
It should be fairly easy to build a $5000 stand-alone stability computer that “learns” the boat’s typical motions under a variety of load and sea conditions, and of course has the boat’s stability book parameters uploaded. It would alarm when motions become unusual, or stability parameters are reached.
Similar tech could also be applied to the container loss problem.
There is certainly room for improved monitoring of tanks, voids, and other spaces. A lot of that could be accomplished fairly inexpensively with lights and cameras in the spaces that provide a video feed to a wheelhouse monitor.
Couldn’t you adapt any of the MRU devices presently being used on DP vessels and interface it with a simple HMI which allows setting warning or alarm set point on any of the axes? Combine that with a good set of draft sensors for, aft, p, s and with some basic geometry the HMI would also show trim, list, etc.
It’s pretty clear from the USCG Marine Safety Manual, Volume IV, that you do NOT include the bulwarks in the buoyant volume when creating the hull model.
I remember that in the 80s a pneumatic de-icing system was successfully tested on a Dutch trawler. On the front of the superstructure pneumatic boots were installed. Depending on the circumstances the timing of the inflation/deflation cycle could be adjusted, the shortest period was 30 seconde.
A disadvantage is that pneumatic systems are expensive, heavy, complex, and easily damaged and probably due to that it never really caught on. Every penny counts you know…
An overview of the several de-icing techniques and their capabilities.
Marine architects answer the questions that get asked of them. Because few captains ask them questions, the architects tend to be ignorant of the answers. If every boat owner/captain in the fishing fleet assailed their marine architects with the hard questions about icing and flooding, we’d probably have more answers than we do now. But few people challenge the stability data they’re given.
After the El Faro sinking, our company detailed a captain to ask our marine architect questions about survivability in case of various flooding contingencies on our boats. The captain was surprised to find the marine architect didn’t have the answers. Turns out stability and survivability from flooding aren’t the same thing, at least as far as some computer stability program are concerned. As with marine architects, computer stability programs answer a narrow set of questions. If you don’t ask more questions, the architects/programs will never come up with the answers.
Moreover, marine architects don’t like working with soft data, and the weight of the ice is not directly proportional to the thickness of the build-up. Icing can be spongy, or hard as cement, and it makes a difference in the weight. MAs don’t like to make guesses on this stuff, so there is a tendency to avoid the question.
RE; vessel icing; it’s always asymmetrical. It’s always heaver one one side than the other. Stability programs should have models in them that take into account heavy lateral icing on either sides, as well as very heavy icing on the bow.
I’ve dealt with severe icing as captain, and as a shoreside person dealing with the consequences of icing. One bitter lesson: iced-over tank vents are dangerous, at least on vessels 2500 tons and smaller. Once the tank vents ice-over you can’t transfer liquids to compensate for listing due to lateral icing.
If the vent runs through a freezer compartment, you’re not likely to get that ice out until the weather gets warmer, and even then reckon in days, not hours. The ice gets in the piping, aspirated in as sea-mist as the tank pants from rolling. Vents that run through non-freezer compartment are not going to be much different. I remember fueling a vessel with an iced over vent to the fuel tank. We blew a seam in the shell plating because of the built-up pressure.
Chainsaws (wear the chainsaw chaps/helmet. You’ll be working on a slick deck)
Hand Tools
De-icing hammers (Get these from Seamar in Seattle. Huge head/chisel but made of very tough plastic. Tough, but light enough to swing for days. If you can’t find these, use a big Dead-blow mallet. Safer and less energ- intensive than a normal mallet.)
