How is the area of the mast measured when the mast passes the deck at two points?

10R 
Question Details

How is the area of the mast measured when the mast passes the deck at two points? This is relevant where the mast is supported in a mast gate, usually above the gooseneck and main boom, and the gooseneck andkicking strap is below the level of the foredeck.

Answer

Class rule J.2 Measured Rig Area states:

"The measured rig area is the sum of the area of the components of the largest rig excluding (certain stated parts)."

The mast below the mast gate (the upper deck level) and above deck level is not one of the excluded parts so its area shall be included in the Measured Rig Area. Where the mast crosses the deck more than once the area is measured to the lowest point where the mast crosses the deck.

Section K.4 is referenced as the method for measuring the mast area and the diagram L.1 shows the lowest spar cross width, m0, taken at deck level.

No rules restrict the shape of the deck in the vicinity of the mast. It is for the owner to specify where the mast deck level shall be taken. If the measurer disagrees with the choice of that point he shall report his opinion in the comment box provided on the measurement form. The Certification Authority shall not issue a certificate and may ask for an interpretation on the specific case.

 j2 figure