HMCo produced straight stock and folding stock anchors. In 1911 the
list of folding stock anchors comprised 27 different models ranging
from 8.6lbs to 1260lbs. I am sure they built other sizes in the
following years.
The 1911 list does not show a 22lbs anchor. The small sizes are
8.6lbs, 12.0lbs, 15.6lbs, 20.0lbs, 25.2lbs, and 31.3lbs.
The next size, 38.0lbs, is the first size for which chain (1/4") is
specified.
The list shows values for Proof Test in lbs. I do not know how this
was determined or what exactly it means but I'd assume this to be
holding power. For what it's worth, the 12lbs anchor showed a proof
test value of 686lbs, the 20.0lbs 1115lbs, and the 25.2lbs anchor 1365
(and the 1260lbs anchor 41700lbs).
L.F. Herreshoff in his "Common Sense of Yacht Design", vol. 2, p. 110
has a lot to say about Herreshoff anchors and also provides data
matching yacht tonnage and anchor weight. He notes that his father
used a different, much more complicated formula which came to
different conclusions.