Bourbon Dolphin capsizes

i had no idea weights and pull had gone up so much, astonishing thanks

 

for my two pennyworth - only thing that can pull a vessel down like that is 'girding' (girting, depends where your from) I'd put money on it. Running the anchor and chain out on a bearing, rig calls out come more to left/right, then more, skipper alters course ,suddenly he's beam on, the chain snags (break or anything knot in cable in locker even) jams solid BANG! over goes the ship, so quick can't do a bloody thing about it!

the five below, either off watch or maybe one in the engine room (modern boats in control room or on bridge) so my bet is off watch in bed! No chance, first thing you know your on the deck wondering what the fcuk! and water starts coming down the passage - fast

No not a good way to go! But what do I know? 17 years as mate on AHTS - no not much!

 

Just some info. recently I have worked on several new build AHTS vessels. None of them had any stability information relating to anchor handling! I asked the appropriate people in the company as well as an ABS surveyor, I was informed that there is no requirement for there to be any calculations done to determine the stability of the vessels during anchorhandling ops. The only calcs I have seen relate to towing and it's effects.
Also there were no calcs done to determine the stability of the vessel if the engine room was flooded, apparently as long as the engine room is double bottomed and there are wing tanks the length of the engine room there is no requirement.

 

Well, I'm not at the office now, so I don't have here the IMO codes, but I'm pretty sure they include regulations for lifting weights operations, among them lifting anchors or moorings on offshore supply vessels.

Here some from other source:
"The residual area AR between the righting lever curve and above the heeling lever curve up to 40 degrees angle of heel (or up to the angle of down flooding, θf degrees, if this angle is less than 40 degrees) shall not be less than 40 per cent of the total area under the modified righting lever curve from 0 degrees to 40 degrees (or from 0 degrees to θf degrees)."
"The angle of down flooding shall not be less than 40 degrees."
"The vessel shall have residual area AR measured between the righting lever curve and the load heeling lever curve to the maximum residual ordinate (see Figure 10), or 40 degrees, whichever is less, not less than 4.58 metre-degrees."
(http://www.nmsc.gov.au/documents/NSCV_Subsection_6A_2nd.pdf)

About flooded stability, that's a good question. I would like to know if there was an (unnoticed left) open acess to the engine room through which a progressive and massive flooding may have happened when heeled. It has been too common a problem for fishing vessels, unluckily.

 

if you see my first post on the topic, I said same, tugs do not founder(quickly) unless the E/R has been compremised
Much has changed since my day but I do remember one of our tugs sank in seconds
What happened was a drill ship( there were many ships converted) came up on a swell and the tug Paris, was under and lost her back third A helicopter was flying by, picked up everyone Ekofisk field 1971 (approx)
These ships could not hold station in a blow, we would pick up all the anchors and tow them into the gale for days

 

Hi Guillermo. Under SOLAS there are certain requirements, they do not spell out specifics for an AHTS. I have been looking for rules / regs and would appreciate knowing of any that directly relate to Anchor handling.

 

riggertroy,
Have you tried the latest IMO IS code?
http://www.imo.org/Publications/mainframe.asp?topic_id=740&doc_id=2509

There is also the IMO's Resolution A.469(XII) “Guidelines for the Design and Construction of Offshore Supply Vessels” and now a new one in 2006. See attached document at the foot of this post.

An interesting paper on this kind of vessels:
http://www.eagle.org/news/TECH/2005/Offshore/25. Modern Offshore.pdf

On engine rooms with double bottom and side tanks, I bring your attention to this point in the attached document (if the wing tanks do not extent the full length of the engine room or are less than 76 cm wide, it may apply):
"3.2.6 Where a transverse watertight bulkhead is located within the transverse extent of assumed damage and is stepped in way of a double bottom or side tank by more than 3.05 m, the double bottom or side tanks adjacent to the stepped portion of the transverse watertight bulkhead should be considered as flooded simultaneously"

Cheers.

 

Guillermo - doubt if a hatch was left open, access to engine rooms tends to be rather awkward these days! the only deck hatches which open and close to these areas tend to be accesses to the bulk cargo areas (these are connected to engine room but doors tend to be closed) It could happen but my guess is the water would flood in via the accommodation entrance in the winch bay and down (?) the by now horizontal stairs to the engine room, force of water would be unstoppable and of course no watertight doors from accom to Engine room control room - not 'normally' needed, just sound proof!!

Don't forget in a 'girding' situation the vessel is pulled on her side and then towed towards the cable/chain/bigger vessel, wouldn't take much to force open and keep open doors throught he accom. and once open, you'd need a very strong man to close the door - he'd have trouble looking after himself never mind the door! Don't think you could blame the crew for that little error!

there is an engine room hatch to facilitate getting big stuff into the engine but this tends to be bolted down - quite an evolution to get it open - for the very reason you mention - nobody likes big lumps of water in the engine room, apart from the stability it tends to make the engines stop running!!!

 

As the heeling momentum and energy to totally capsize, just by side pulling, a 75 m AHTS vessel like this is probably quite high, I'm rather inclined to think about the open access downflooding possibility, whatever the access and the flooded compartment has been. I have some personal experience in forensic engineering on a couple of fishing vessels which sinked in a matter of very few minutes because of this, also with sleeping off watch crews not being able to reach deck on time to save their lives. See Post #40 at the 'famous sinkings' thread, on the 'Gaul' and one of such cases here in Galicia.

Going to sail right now. Gloriuos weather!

Ciao!

 

Riggertroy is right. Reviewing agencies only require the standard OSV's IMO intact, damage & wind heel stability calcs. The Tow Pull criteria is tagged on only for towing and AH (over the stern, not the side!).
The Lifting criteria is required only when lifting with onboard crane/Aframe.
Looks like flooding was not involved; This type of vessel is W.T. from focsle to stern and the E.R. is forward. She is floating level right after capsize (for a day?) as seen on attached picture.
As stated by others I strongly suspect 'girding'. It will be shown that once the aft deck port side is submerged and the bilge stbd side comes out of the water the 'INTACT righting energy' offered is minimal because the focsle does not 'kick in' ! The 'wedding cake' design with its high VCG does the rest, in a few scary seconds.
The HP and BP have increased to the point where a boat that size can go from 'routine' to 'turtled' in a few seconds. New specific criteria must be researched and applied.

 

As the new builds I was involved with were started in 2004 & 2005 I think the 2002 code applied.

I still find it hard to believe that the engine room of a vessel is not included in the damage stability criteria because it is double hulled, what happens if due to a collision one of the FIFI intakes failed - no pump fitted to the bilge suctions in the engine room could cope with that sort of flooding, what will the result be of the engine room flooded?

Also on a 2005 built AHTS I found that the point of vanishing stability for when we were to commence anchor handling ops was around 58deg, girting of the vessel will likely result in her going over and not coming back up, hence I always used a gog when towing (even short distances) and when running anchors if possible and practical I used the shark jaws or towpins, and on an older vessel the norman pins came in handy a few times when the barge's winch operator made the wrong move for us.

One point that seems to have been missed - engine room blower intakes - at what angle did down flooding occur though them in the case of the Bourbon Dolphin? was this a contributing factor to her not coming back or was she simply dragged past her point of no return?

The IMO criteria as I know them have no reference to anchor handling when things go wrong, maybe it is time to look closer?

The Stevns Power incident a few years ago where the entire crew was lost was another one that happened during AH ops. Seemed that age of the vessel was partly blamed there.

 

Angle of vanishing stability, that you quoted, seems very small, not enough to wet the engine room intakes, which are very high up, the ship would need be around 110 degrees to to start to flood through those assuming they were low I dunno they are sometimes not much below the funnel height from my recollections Maybe as someone said no flooding occured, she was simple pulled over

 

um sorry I should have read those last few posts, first before I said same thing,
the wedding cake, well as the ship heels, she does get on more waterplane, like ferries , big slab sides they just get more stable as they heel as do yachts, righting arm increasing, But yes I can see these hull could just be stable, then wham over
but we all assume, what IF, like what if she was light by 100,s tonnes fuel? and so on

 

Rigger Education

RiggerTroy, some of us (me at least!) have no background in these Tugs or towing. But I'm very interested in learning more about the principles involved and the terminology and devices used. Every wanna-be Seaman can use all the information and ship-handling wisdom he can find.. Sooner or later it will apply, even on a small boat.

Can you define those exotic (to us) things like Gog, Girt and Shark Jaws, and tell us a bit about how this stuff is used? I'm looking at "Primer of Towing" by George H. Reid. The index has zero entries for "G" ! Hmmmm... Is there a better book?

Maybe we can add a short section to the Stability page on the Wiki about towing.

It certain seems like a tow line should always be restrained somehow from jumping to port or starboard!

Educate us a little??

 

Why! who doesn't use a 'gog' wire when towing! apart from the odd idiot trying to kill his crew - incidentally a sharks jaw CAN be used for the same job, just, at a push! But I wouldn't (again) unless forced to or the tow was VERY short!!

Terry - confusing 'tug talk' I know and I doubt if you'll find much of it anywhere else (bit like sea language in general really!!). for a start the gog or gob wire is a wire that connects to the towing wire and the stern (close) of the vessel, it prevents girting or girding (the pulling over of the vessel by her being pulled beam on and pulled sideways by the tow) As you may be aware the best point for the tow to be attached is somewhere about amidships but this means that the tug can be easily swung under weight about it's axis; bean on and it tends to go over! It can happen very quickly and will easily kill your crew/sink your tug! Not quite what we're about is it?! the gog wire as I said runs from the towing wire (normally a large running shackle) doen to a fixed point on the deck aft (the gog eye) (but the wire ain't fixed) the wire then runs back to another winch from where it's length can be controlled. Usually short in to keep the towing wire over the tugs deck, but it can be lengthed to assist turning the tow (never an easy job, done slowly in 2 to 5 degree increments) Well hope that rambling explanation helps - trouble is it goes on a bit which is why we use single (wierd?) words to explain the happening!