What are hollows ?

After reading the recent discussions about the "hula" and studying the ACC rule, can someone let me have a definition of a "hollow" ?

Is the abscence of hollows the reason why ACC boats are so slab sided ?

Regards,

Mark

 

Hollow = any concave portion of the hull, specifically any place the measurer can cause a straight edge to touch the hull in two places and see a gap between the hull and the straight edge between the two points of contact. This is to prevent indentations at measurement points. I doubt the sides are effected so much as the bow and stern, where the waterline is measured. A completely rounded shape would be legal as long as the curvature is all convex. A hull similar to a giant Etchells would be legal, but a hull like the schooner yacht America's would no longer be legal in the America's Cup because of the flare in the bow sections and hollow in the waterlines near the bow.

 

Thanks Stephen,

I have seen, in the yacht design school literature, reference ton "hollow garboards".

I guess "garboards" is a US term ?

Would a craft with hollow garboards have a more wine glass shape to its midsection than a yacht with no hollows ?

Regards,

Mark

 

That's right, but it has become clear that filleting the hull into the keel in section hurts performance, so the practice is pretty much dated.

 

Mark

Garboard is one of many Dutch terms (stop grinning yipster ) that were introduced into English in the 16th Century and earlier, a few later. It comes from gadaren, to gather, and boord, board. It is the seam between the first strake and the keel, stem and sternpost. It also meant the actual first strake itself i.e. the strake that was rabbetted into the keel and end posts. It got the name because of the added difficulty of caulking into the keel end end posts.

It became a term on iron ships and is still the technical term for the steel or aluminum strake adjacent the keel plate on modern vessels.

But if ever you were a lad who went to sea on a yacht, carrying belongings in a knapsack, saw the boss, signed your name on the roster, but refused to work on the cruise, and was keelhauled, then thank the Dutch, specifically the Frieslanders.

Michael