Ground tackle load calculations

[safewalrus]

Your grasp of the simple task of a Risk Assessment not only appears flawed, it is!

Your Engineering ability is not open to questionability is it?

Unlike your definition of 'worst' apparantly is! my definition of the word is -

inferior, least likeable, lowest level, most severe!

Unless I'm wrong your idea would be the complete opposite or something completely different! As I said earlier we could disagree about this possibly pointless activity for quite some time!

the Walrus

[MikeJohns]

Originally Posted by safewalrus

Your grasp of the simple task of a Risk Assessment not only appears flawed, it is!

And you have obviously never been involved in Professional risk assessment.

Originally Posted by safewalrus

Your Engineering ability is not open to questionability is it?

Always ... thats why we review each others work

Originally Posted by safewalrus

Unlike your definition of 'worst' apparantly is! my definition of the word is -
inferior, least likeable, lowest level, most severe!

Worst case in my parlance means the highest load. What exactly are you saying?

Originally Posted by safewalrus

Unless I'm wrong your idea would be the complete opposite or something completely different! As I said earlier we could disagree about this possibly pointless activity for quite some time!

You are

[safewalrus]

OOOO! tut tut!

temper temper!

bl**** abo!

So what kind of an Engineer do you think you are (more for the entertainment of others than the record)!

[jedclampit]

Hey…just my two cents…but I agree with PAR.

I’ve worked as a coastal engineer for the last twelve years so I know of which I speak. This is not a task to be taken lightly.

There are many forces on a ship moored or anchored…and all which require accurate understanding. I don’t feel that you should be designing an anchor system for those storm requirements. Most mooring systems are designed based on specific local topographical conditions and the average annual wind direct and speed, wave heights and periods and current flow directions and not for hurricane winds, waves or surge. Why would you want to carry that kind of weight on a ship? In marine (coastal) construction all moored vessels are required to move off mooring and into a sheltered harbor when wind conditions increase above 15 knots and/or seas increase over 3 feet. Cruise ships usually move off their anchors when winds increase over 35 knots (and some cruise lines in as little as 25 knots of wind). I know stories of men whom have died due to anchors dragging in high winds and threatening the safety of the ship…

The actual calculations will require the understanding of all of your variables. The ships profile above and below the waterline, topography of the mooring location (depth and slope and materials of the sea bottom) and the fetch (distance and direction to any landmass that would impede the wind and waves). You can always make generalizations and most designers and retailers for ground tackle will or should be able to assist you with a conservative design for your ship.

There are also many books that I should point out to you (mooring systems for small crafts), but if you really want to design a storm anchoring system for your boat I would suggest that you find a Naval Architect, Coastal Engineer or Ocean Engineer to assist you.

[bhnautika]

Whoa lets slow down. I see “risk assessment” as being used in relation to the holding power of the anchor in whatever material is there and in what conditions. As for the “worst case loads” that is the amount of load likely to be put on the system as a whole from anchor to bollard. One is for the skipper to decide at the time, the other for the necessary equipment.

[jedclampit]

LOL...I guess that I should have read the whole thread....OPPS!

If this is for an insurance settlement than I would seek the opinion of a Professional Coastal Engineer who can give expert testimony, but watch out…you may find that his or her testimony might support the findings of the insurance company (they have deep pockets and probably already have experts on their side on the table).

[jedclampit]

get back on subject...the question was not about risk management...

[safewalrus]

Your right Jed, never was; the boat had a problem as I read it, probably dragged and got bent! Insurance's are arguing - you know the style - they promise the world - you pays the premium - the problem happens (it shouldn't but **** happens) the insurance people look for ways NOT to pay (anywhere else it would be called theft; the guys paid for the service! but insurance companies are crooked -no specifics just all bloody crooked) so someone gets called in to help, hes a member of this forum and asks for help, in the process of establishing what kind of help someone shoots his mouth off and gets it wrong! We have a slanging match I enjoy it the other daft sod believes it and bursts a gasket (red letters!) Some others dive in, one guy actually offers the right help (yep mate you!) And we're still awaiting the result of the slanging match ! which has probably defused itself now! Pity I was enjoying myself!

[Ari]

Huh..thank you for the explanations walrus. The RAM that I have is not compatible to the situation The gasket is o.k I think..what actually blow was the relieve valve..it made to blow anyway.I do really enjoy the info from this discussion

[MikeJohns]

Originally Posted by safewalrus

OOOO! tut tut!
temper temper!
bl**** abo!
So what kind of an Engineer do you think you are (more for the entertainment of others than the record)!

It appears you are trolling for an altercation.

No temper just facts, I put the answers in red simply so you could differentiate between your writing and mine,I have changed it to black since red offends you.


You confused load calculation with risk assesment after attacking me erroneously for using the word Presume. Each time I have simply tried to point out where I think you are in error. If you have a valid point to debate then do so. Please don't resort to boorish insults and insinuation. This forum deserves better.

If you wish to know what I do read my bio. Unlike you I don't hide behind a non-de-plume. Perhaps you would like to give your name for future reference ?


Regarding anchor loads my point was that a definitive number is a hard call and depends on much more than wind loading. A big problem in the marine indiustry is doing a nice neat static calculation for theoretical loads while ignoring the dynamic loads. Even with computer generated FEA models for the dynamics you get such a complicated solution that you cannot check it .

What happens is we fall back on simple proven rule of thumb for those complex issues such as the size of an anchor chain. Why rules of thumb often triumph over calculation is an important concept and should be clearly understood.

[CDBarry]

The API has a recommended practice for mooring design. This would be a useful standard to look at, especially since it is meant to be applicable to keeping offshore floating platforms on their moorings in very severe weather.