Alistair_Heaton
Mechanical
This is hot news at the moment mainly due to who was killed.
Seemed to go down very quickly.
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Super Yacht sank in the med 3
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This is hot news at the moment mainly due to who was killed.
Seemed to go down very quickly.
TugboatEng
Marine/Ocean
This appears to be the location of the engine room ventilation. That would certainly let water in at 88 degrees. Perhaps there is a procedure to seal those hatches when rigged for sailing. Was the vessel sailing or motoring during the storm? If motoring, these hatches would have been open.
If hit by a wave from the beam that cause them to lay over, well there is certainly a lot of glass on the side of the house.
If hit by a wave from the beam that cause them to lay over, well there is certainly a lot of glass on the side of the house.
The AIS traces showed it at anchor before apparently breaking free and suddenly no longer being tracked.
TugboatEng
Marine/Ocean
Ships and boats tend to drift broadside to the wind. That AIS track shows otherwise. I don't know if this applies differently to keeled boats.
From what little I have seen, cargo ships have a fairly uniform side profile both above and below water; the have all the shaping of a rounded brick.
Sailing ships, which I once had considerable interest in, tend not to. In particular, the mast of the Bayesian alone represents a considerable surface for wind to apply a load forward of the middle. It also looks to keep the foresail wound around its rigging, adding more area for the wind to act on. If all other loads are balanced, those alone will turn it downwind.
Sailing ships, which I once had considerable interest in, tend not to. In particular, the mast of the Bayesian alone represents a considerable surface for wind to apply a load forward of the middle. It also looks to keep the foresail wound around its rigging, adding more area for the wind to act on. If all other loads are balanced, those alone will turn it downwind.
There are also two forward doors for small watercraft to be aboard and some witnesses thought it went down by the bow; this is in keeping with an early speculation that an access door had been left open.
It looks like there are already efforts to muddy the water:
Dragging the anchor doesn't normally cause a ship to sink, so the 16 minute reference makes no sense. It makes sense to know how long it was from the time it began taking on water until it sank.
I can imagine that it was mainly OK dragging the anchor by the bow, but at some point the anchor line was lost, allowing the drag on the mast and forward rigging to turn the ship sideways and heel. If a forward garage door was open that would allow the door to go under, flooding the forward portion and maybe the rest of the yacht; few details on interlocks and watertight doors.
I would be surprised if it was a knockdown with no sails up, even with the keel up. That is still a more than literal ton of weight.
euronews says:
However, it is laying on its right side, so the starboard garage door may be open and the divers cannot see it.
Interesting comment:
Another superyacht recently sank at anchor from leaving the garage door open in somewhat mild seas so it's not an unheard of cause.
It looks like there are already efforts to muddy the water:
Dragging the anchor doesn't normally cause a ship to sink, so the 16 minute reference makes no sense. It makes sense to know how long it was from the time it began taking on water until it sank.
I can imagine that it was mainly OK dragging the anchor by the bow, but at some point the anchor line was lost, allowing the drag on the mast and forward rigging to turn the ship sideways and heel. If a forward garage door was open that would allow the door to go under, flooding the forward portion and maybe the rest of the yacht; few details on interlocks and watertight doors.
I would be surprised if it was a knockdown with no sails up, even with the keel up. That is still a more than literal ton of weight.
euronews says:
However, it is laying on its right side, so the starboard garage door may be open and the divers cannot see it.
Interesting comment:
Another superyacht recently sank at anchor from leaving the garage door open in somewhat mild seas so it's not an unheard of cause.
GregLocock
Automotive
The alarmism I was alluding to is that a 90 deg knockdown is perfectly survivable, to the extent we carried on racing afterwards, and probably won.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
TugboatEng
Marine/Ocean
What was the beam of your vessel that got knocked down? Was anyone sleeping inside? Did your boat have an engine room with ventilation?
GregLocock
Automotive
Not the point. The point is 90 degrees is survivable if you design for it. Did the DFMEA include knockdown as a criterion?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
TugboatEng
Marine/Ocean
Sure, the knockdown is survivable for most vessels. The trouble is that on a 40 foot wide vessel there is a lot of potential for fall injury and death.
Anybody remember Cougar Ace?
Anybody remember Cougar Ace?
LittleInch
Petroleum
There's now mention of a down draft hitting the vessel. Also could the fact that it was anchored affect how the boat reacted?
So a big downdraft and the anchor chain pushing in kiddie directions pulled the bow down?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
So a big downdraft and the anchor chain pushing in kiddie directions pulled the bow down?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
TugboatEng
Marine/Ocean
It is possible the forces from the anchor could have breached the hull. The anchor transfers forces to the hull through a winch. It's possible the foundation failed and caused a breach. The anchor is also attached to the hull via weak link. Maybe the weak link wasn't weak enough and that damaged the hull.
I don't see any probability on a downdraft strong enough to push the bow down and sustained enough to hold the bow down.
A sudden change in wind direction could cause the boat to make contact with the anchor chain.
I don't see any probability on a downdraft strong enough to push the bow down and sustained enough to hold the bow down.
A sudden change in wind direction could cause the boat to make contact with the anchor chain.
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Alistair_Heaton
Mechanical
What's the dynamics in a water spout and boats in general?
TugboatEng
Marine/Ocean
A boat doesn't float in aerated water. There was a aemi-submersible oil rig that capsized some time back because the well had a blowout and the gas aerates the water enough that it lost buyancy.
Stability is a matter of keeping the center of buoyancy above the center of gravity in all conditions, and it's possible.
But for most ships and boats, including the subject one, not a likely design criteria
But for most ships and boats, including the subject one, not a likely design criteria
The depth of the aeration would need to exceed the freeboard (caveats about waves and heeling) to get them to sink. The little ones that I have seen in the news are because someone cranked up the anti-ice aeration too high, so the water density was lowered all the way to the aerator depth. I think people have drowned this way from falling into water treatment aeration tanks.
I would not expect sufficient churning of the water to do the same to a yacht from a water spout; perhaps a deluge of water directly onto it? Even that requires open hatches.
Google isn't aiding in finding a boat sinking at the dock from aeration, but this is one amusing thing I found about dealing with an upset condition. Who would have guess that bolting ladders with the rungs vertical on the sides of the cabin would have been smart? Sure people make fun of it, but it pays to be prepared.
There are a bunch of Navy ordnance videos where a explosion amidship lowers the density of the water enough that the hull, damaged by the blast in the uplift portion, if finished off when the remaining buoyancy is at the bow and stern and folds it like a church luncheon chair because the middle isn't being supported by the new foamy water installation.
I would not expect sufficient churning of the water to do the same to a yacht from a water spout; perhaps a deluge of water directly onto it? Even that requires open hatches.
Google isn't aiding in finding a boat sinking at the dock from aeration, but this is one amusing thing I found about dealing with an upset condition. Who would have guess that bolting ladders with the rungs vertical on the sides of the cabin would have been smart? Sure people make fun of it, but it pays to be prepared.
There are a bunch of Navy ordnance videos where a explosion amidship lowers the density of the water enough that the hull, damaged by the blast in the uplift portion, if finished off when the remaining buoyancy is at the bow and stern and folds it like a church luncheon chair because the middle isn't being supported by the new foamy water installation.
TugboatEng
Marine/Ocean
The irony is that boats and ships tend to be much more stable when upside-down than they are right side up.
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