Bourbon Dolphin capsizes

Ace mate, careful we agree on something! As you say something should be done but probably won't - it would be nice to see better quick relase systems but I've a feeling that the reason it didn't work was the extreme angle the wire was at when the order was given; and automatic releases are worse than unlit bouys! downright bloody dangerous to all concerned!

When it come down to it I think it was a case of sheer bad luck! A lot of inponderables that shouldn't have happened did AT THE SAME TIME, if they'd have happened one at a time no doubt a few people would have got a little interested/worried but that would be all - everything to happen at once, well....

Whilst the BD may have had all the extras they weren't put there to be 'nice' but primarily because all those extras can mean the difference between getting the next charter or not! After all the owner is in the gme to make money! Not that that is a perogative of the shipowner - in that case everybody is!

Look forward to our next encounter - this one is about done (save for the wash up after the inquiry!)

the Walrus

 

I think they will do something. It will take time, as usual, but will do. Too scandalous a disaster for a jewel of the AHTS world fleet. Some aditional exigencies and/or limitations will be posed to these vessels. I'm atonished to learn for an AHTS vessel "....it appears to be a basic supply boat stability booklette with no mention of towing, or the cargo storage reels, chain lockers, etc." (Cappy Chuck's words). If this situation is generalized, which I'm not sure about, something will be done for sure, like when the sinking of the "Estonia" (http://www.onnettomuustutkinta.fi/estonia/)
"The ESTONIA accident prompted an extensive investigation within the International Maritime Organisation (IMO) on all aspects of ro-ro passenger ships' safety. The work has led to improvement of existing safety regulations and development of detailed new ones of which a significant part has already come into force."

I'm really interested in knowing the coroner's report.

 

In Norway this accident immediately started a discussion on more detailed rules fr what kind of work or load a boat can take. I think we have a kind of committee working on a proposal.

 

This is not exactly correct. US stability requirements do require that towline stability be done for a vessel capable of towing so these conditions must be run. What is not required is over the side loading, except for crane calculations if there is a crane that is capable of doing offshore lifts fitted.

As well variable weights are considered in all stability manuals to take care of items such as wire rope, chain, ROVs, etc. These are not considered a part of lightship or deck cargo, which was the stated concern of Capt. Chuck in that the VCG of these items exceeded the max uniform deck cargo height as mentioned in his stability manual.

Towing conditions are ONLY required for vessels fitted with towing devices, such as towing winches, tow bitts, etc., so standard PSVs/OSVs are not required to do these particular calculations.

This is for US requirements, I am not sure of what the European vessels must meet, however I would assume that it is similar in scope.

 

Thanks, Ace.
So Captain Chuck vessel's stab manual should contain towing as well as wire rope, chain, ROVs, etc. information, which it seems is not there. (Chuck?)

What are the towing criteriums you follow? The Tow and Self Tripping criteriums ones? Any other?

Do you think it could be sensible and practical to also study over the side loadings? Would it unnecessarily or heavily condition designs?

 

The towing criteria that is required is that found in the Code of Federal Regulations, 46CFR 173.090 Subpart E-Towing.

On the stability manual that I commented on, I said that each stability manual must have cells to enter variable weights. This is where things such as wire, ROVs, chain, etc. that are NOT deck cargo are accounted for. I would be very surprized if Captain Chuck's manual did not have a place to account for these variable weights.

As far as over the side, I have looked at it and the problem is more of dynamics. You can hang a static load over the side and get the resultant heel easily, but dynamics sort of muddy the results into maybe OK, maybe NOT. This would really have to be worked out for this to be reasonable I believe.

 

In the stability booklette as approved by the USCG - there is no mention of towing whatsoever. The only place where it figures is in the 'Minimum allowable KM". There are CFR requirements for weather, towing, etc. The stability booklette just takes the most conservative KM and then plots that curve as the minimum allowable KM. They do take towing into account somewhere in the calculations for figuring the minimum KM but no mention of conditions, weights, or requirements. We have the same minimum KM restictions whether we are hauling cargo or trying to stretch out a 12,000' system in 5500 feet of water. They don't give us many tools for trying to figure out the stability as it changes, such as transferring ballast, etc. It would require another long-hand calculation that not many of the captains are willing to do. I am sure (at least I hope) that there are requirements on the books to computerize the stability calculations in a user-friendly format that would allow the vessel crews to keep track of stability in real time.

...although that, for some reason, also brings to mind the saying "If you try to make it idiot-proof - they just go out and design better idiots."

--Chuck

 

In our manual there are spaces for variable weights - but we use three of these to insert three tanks that they forgot to place in the stability calculation sheet. I am not impressed with the attention to detail.
--Chuck

 

The way the manual is made is to make it conservative and easier for the masters to use. As you say, there is a safe allowable curve. This curve is derived from extensive calculations that include many different criterias, such as weather, towing, crane lifting, damage, etc. The curve represents the WORST case allowable KG for any of the criteria checked at any level of loading. For example one area of the curve may be governed by towing, another area damage, another area crane, or so on. This is the simplest way that it can be provided to the vessel without a autostability program. You don't see the actual GM with this method, but that is taken care of in the calculations performed by the naval architect in the creation of the KG curve.

Sorry that the guys making your manual didn't take any more effort to make it easy to use. Seems a lot of designers today just do not take any pride in their work any more.

 

Trouble is it ain't just designers like that! Tis everybody busy taking the money, and to hell with the pride! some still do but they are the exception rather than the rule and normally only in small family run jobs! Sad

Funnily enough a lot of those that do (in the marine world anyway) actually subscribe to this forum - and as we know there are not too many of those!

 

I had a look at it. Seems to be oriented to evaluate the momentum effect of full propeller(s) thrust with rudder(s) at 45º, taking as pivoting point the tugging bits, instead of the 70% of the bollard pull at the side and the arm down to the CLR, as for the Tow Tripping criterium. Interesting.

Ability to theoretically resist an statical full whinch power pull over the side at the staghorns when anchor handling, and still have positive righting arms, could be one of the exigencies for AHTS vessels. I haven't done numbers, but as a first guess if the GMº at the AH working condition is kept up to 1.5 m with a typical GZ curve, vessels should be able to comply.

(Some minutes later).....mmmm. Thinking twice, the problem are the vents at around 45º. Probably it wouldn't work. I'll try to review this on monday at the office.

 

Just found this on the net:

http://www.imca-int.com/documents/core/sel/safetyflash/2007/IMCASF05-07.pdf

 

So something is being done. Others of you will know better than I, but this seems a move in the right direction. The effectiveness will depend on the details of compliance, of course. Any opinions?

 

Good find, look like they take the moust importent mashurements.

I know some don't use the hrusters while doing bolard pull because the waterflow from the thrusters are disturbing and decreasin the efficensy off the propellers + they rob some power from the main engines so making a seperate bolardpull including the thrusters is a good idea.

 

www.aftenposten.no

Aftenposten is reporting that Bourbon Dolphin was taking more load than it was certified for.

Bourbon Dolphins max bollard pull is rated at 180tonn while it during operation was recorded pull up to 240-300tonn(posibly 33o tonn prior to capsizing)

New regulations are comming into effect because of this including different pull on towing and anchour handling and also regulations saying a ship can only do operation it can handle itself without asistance.