ISO 12217-1 Calculation Swamped Stability and Buoyancy Test

Discussion in 'Stability' started by Arteaga27, Mar 21, 2024.

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1. Joined: Mar 2024
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Arteaga27New Member

Hi, I would like to know if it is possible through calculations to validate Swamped Stability and Buoyancy indicated in Annex F.
In the standard you can read the following: "The methods described in F.2, F.3 and F.4 shall be used, either by actual test or equivalent calculation. "

I want to know about equivalent calculations.

I haven't found anything in forums or books.

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TANSLSenior Member

Of course, when one is carrying out the basic project of a boat that must comply with ISO standards, there is no other solution than to verify compliance through theoretical calculations. These calculations are no different than those required for any other ship that must comply with, for example, SOLAS. Nothing special, then, in the ISOs.

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Arteaga27New Member

Please could you tell me where I can read about these equivalent theoretical calculations, because I understand that in these tests water should enter the boat and comply with stability and flotation. What I don't understand is how to calculate the amount of water that would enter. Thanks

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TANSLSenior Member

The swamp test, as I understand it, consists, with the boat in a certain load condition ( which we will call Swamp Test Load Condition STLC), in the following:

- Real test:
1.- with all hatches and watertight doors closed:
2.- fill all floodable spaces with water as high as possible (that "highest" has to correspond, logically, to the lowest point of the bulwark or side because from that height the water overflows over the bulwark) .
3.- check that the boat maintains a large part of the bulwark above the waterline. That is, the ship, once flooded, retained enough buoyancy to not sink completely)
- Therefore to carry out the theoretical verification:
1. The total volume of water that can be shipped is calculated up to a height that corresponds to the lowest point of the bulwark/side. (see attached picture)
2.- calculate the weight of that volume of water and add it to the weight of the STLC.
3.- With this total displacement, the draft to which it corresponds is interpolated into the hydrostatic values.
4.- it is verified with that draft, that part of the bulwark is out of the water​

The STLC load condition must be the light ship + plus the weights indicated in table F.5 of the standard, placed so that the trim of the boat is the design trim.