Stability criterion – bottom emersion angle

[Kruk]

How the bottom emersion angle can be calculated, and how it can be included in stability criteria ?

[Peter Edmonds]

Bottom emersion angle did appear in Australian commercial vessel simplified stability criteria (essentially where KN information is not available), but does not appear in  current criteria.

Currently downflooding angles are required. These angles can be evaluated using the same procedures.

Simple procedure:

• Draw upright waterline on relevant transverse section of the vessel.
• Draw line from intersection of waterline and  vessel centreline and bilge emersion point (or downflooding point, or other).
• Record the angle.

More precise ;procedure:

I have used this with Hullform software, but  haven’t had occasion to try it in DELFTship.

• Set up model to required displacement and LG.
• Using free trimming hull  balance, heel vessel progressively until required ;point is at the waterline, in an end  view.
• Print this view for  inclusion in the relevant document.

Peter Edmonds

Naval Architect

Perth   WA

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