Inclining experiment

Well, we are discussing cutting and welding, then a well engineered platform temporarily welded to the superstructure that can take these loads seems less destructive than cutting access panels. Or anchor points welded on that can receive the feet of such a structure. Then the weight of said structure is part of the test weight.
The original design team, in possession of hull form data, and all installed components must have a reasonably close theoretical value for stability, so will know how much weight the test will ultimately require.
Of necessity they have the structural skill on hand to design a platform for that weight, and knowledge of the vessel's primary structure so as to determine the location for mounting the temporary platform.

And if such tests are unavoidable going forward, it becomes a trivial additional expense to include the mounting brackets for their standard platform.

 

Ok Tansl, let's suppose that the total sum of the inclining weights is W.
And that they are effectively in the centre of the vessel, so that we have no heel and no trim.
If we had 0.5W to port, and 0.5W to starboard, arranged so that we still have zero trim and zero heel, is that not effectively the same?
If we now want to move 0.1W from the centreline to starboard, then this could be achieved by moving 0.05W from the port side to the starboard side?

I think that DC has the best idea (mentioned in his post above) re welding on temporary platforms to each side of the vessel, amidships, at the height of the main / weather deck.

 

Doesn't rolling ang chucking count?

 

Hahaha. Nice one

 

Yes, it is equivalent, not the same.

But what do you get out of it? You have to place W weights to starboard and then move those W weights to port. It is that simple, I do not see that any trick can be used.

I would have to be in a very extreme situation to study, I say study (not apply), that option. But you better ask the OP to see what he thinks.

Rolling, of course (I do not understand what is chucking) Note that we are talking about moving probably more than 30 weights. These weights should be placed as far as possible from the center line, in premises that are full of seats and other furniture, which makes it impossible to find physical space to place them, apart from the problem of moving them through all that network of obstacles.

 

To stop it. To place chocks. Just one the many meaning of the word.

Ours is a cat passenger ferry. We removed some of the seats to make way. Any trained personnel or NA doing the inclining ex can approximate the amount of weight needed to incline a ship to 2 to 3 degrees and then decide what type of weight can be used. For our case, we are in access of a warehouse full of unused fire bricks. It was handy and lots of labor on standby so we used it.

What would you use for a large bulk carrier?

 

Another of the existing problems is that the ship must have a weight as close as possible to the empty ship, with all its weights and these placed exactly in their places. Therefore, removing some pesos and replacing them with others, in another more convenient place, is not correct and, at least in my country, the Administration does not allow it.
In the "large" ships in which I have intervened (around 130 m in length and some of them passenger), we used iron ingots, between 3 and 5 tons, with their certified weight. A small boat was used to position ourselves in the fore and aft perpendiculars in order to determine the drafts as accurately as possible at those points to determine the average draft and the existing trim. Then the hydrostatics of the vessel with this trim were used for the calculations. The density of the water was measured at a depth of 4 or 5 m. The test was carried out at the first or last hour of the day, in which the wind is very light, to avoid that the wind could cause the boat to list indeterminately and, of course, the sea had to be totally calm. These and some other "precautions" were mandatory. A delicate process, as can be seen.

 

Very delicate.

 

@naserrishehri
You said you could use cranes, capable to lift the boat. So you could check the feasibility for an "inclining experiment in air", for example described in chapter 9 "The Inclining Experiment", section 9.5 "Inclining in air" (in The Principles of Naval Architecture, Intact Stability, 2010, SNAME, p. 63).
(David Cockey was pointing to it in #16, I don't know the mentioned ISO either.)

 

Nothing about inclining test in ISO 12217.

 

Interesting. I don't have a copy of ISO 12217. What does ISO 12217 say about determination of the vertical center of gravity?

A previous thread contains text claimed to be from ISO 12217 D2.2 (or E2.2): procedure for an inclining experiment in air https://www.boatdesign.net/threads/procedure-for-an-inclining-experiment-in-air.45924/page-2#post-608241

b) an inclining experiment in air using a known length of suspension and moving weights transversely (as in
water), the results being corrected to the appropriate loading condition;​

In the same thread the the convenor of the ISO working group that developed ISO 12217 also posted about the use of air-inclining tests for determining the vertical CG height for ISO 12217.
procedure for an inclining experiment in air https://www.boatdesign.net/threads/procedure-for-an-inclining-experiment-in-air.45924/page-2#post-608251

In another thread thread Chris Barry said in reference to T&R Bulletin 9-01: Standard Guide for Conducting Small Boat Air-Inclining Stability Test (2015) (bolding added):

More information about SNAME T&R Bulletin 9-01

T&R Bulletins & Reports | SNAME https://www.sname.org/publications/T-and-R-technical-research
T&R Bulletin 9-01: Standard Guide for Conducting Small Boat Air-Inclining Stability Test (2015)
Small boat operators, builders, buyers, accident investigators, and others may be required to determine an accurate lightweight and center of gravity for their boat in order to apply stability criteria or perform other analyses. The conventional in-water stability test can be difficult to perform accurately on a small boat, so an air inclining stability test may be specified. This guide is prepared to help standardize and explain the process for an air inclining test. This guide provides the marine industry with an understanding of an Air-Inclining stability test for a small boat. It contains procedures to ensure that valid results are obtained with precision at a minimal cost to owners, shipyards, and the government.

The guide is not intended to direct a person(s) in the actual calculations of the lightweight and centers of gravity, but to be a guide to the recommended procedures required to gather accurate data for use in the calculation of the lightweight characteristics. A complete understanding and documentation of proper procedures to conduct a stability test is paramount to confirm that the results gathered during the test can be examined for accuracy, especially by third parties subsequently reviewing the data.

This guide is recommended to be used for all small boat capable of being lifted safely with forward and aft pick points capable of supporting additional inclining weights to be used for the stability test or with suitable sling arrangements



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Look vaguely like there might be.

 

Same result, just different means.

 

As noted HERE, if you can lift it, you can place load cells on each lifting point and obtain the total weight as well as the LCG.
From this you can do an additional check against your light weight survey and hydrostatics.

 

All that ISO 12217-1 says (which is the applicable standard for this boat) is the following:


From my point of view, the standard mentions the words "inclining experiment" but does not say anything about it. So yes, you are partly right. Maybe I should have qualified my answers.