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3.3 Hamilton-Kenyon Model
11 Compartment Parallel (TIIa-11F6) (aka DCAP)
NAUTILUS Dive Planner is the only commercialy available
decompression software product to liscense the Hamilton-
Kenyon decompression model for use in generating
decompression schedules for the technical diver.
The “model” has been incorporated into some proprietary
rebreather decompession computers, most notably the Cis
Lunar and others to be available shortly. Some of Dr.
Hamilton’s algorithms for oxygen handling have been used
in many of the popular dive computers. Until now the only
way to get “tables” using the Hamilton-Kenyon Model was
to have access to the famed Key West Consortium Tables
which were the basis for most of the trimix diving done during
the 1990s, or to have tables provided by NOAA during the
USS Monitor projects (NOAA Trimix 18/50 is based on
Hamtilon-Kenyon Model) or to have a set of tables created
on a custom basis by Hamilton Research Ltd. Dr. Hamilton
has created highly reliable tables using the TII-11F6 model
for such notable dive operations as: Key West Consortium,
Casadore Project, Pillar Project, WKPP, Andrea Doria
Expeditions, USS Monitor Expeditions and many others.
NAUTILUS is fortunate to have been able to liscense the
Hamilton-Kenyon Model for the NAUTILUS Dive Planner
Software. The relationship between R.W. Bill Hamilton and
NAUTILUS co-author Joel Silverstein goes back more than
a decade. The two have worked on many projects together
including authoring two texts on oxygen enriched air diving
for NAUI and for the YMCA. They were co-authors of the
NOAA Diving Manual sections on Nitrox and Mixed Gas
Diving and were the principal and co-investigators for the
Decompression Survey of Air and Air with Oxygen diving
for the US Navy Biomedical Research division. Mr.
Silverstein has relied on the Hamilton-Kenyon Model for
his personal diving and that of his pojects since 1991.
The Hamilton-Kenyon Model has been referred to over
the years as the DCAP model. DCAP is not a model it is a
computer analysis program that allows Dr. Hamilton to create
and model decompression profiles that extend far beyond
the uses and needs of the technical diver.
The computational program identified as the Hamilton-
Kenyon algorithm uses, in our internal terminology, the
Tonawanda IIa model using Matrix MF11F6 computed with
Hamilton Research’s DCAP. It uses a Neo-Haldanian
computational algorithm designated Haldane-Workman-
Schreiner. It uses 11 halftime compartments ranging from 5
to 670 min. The ascent-limiting matrix was developed to
permit deep air dives using air decompression without
compromising established decompressions from short,
shallow air dives. The development was empirical, based
heavily on experience, but formal statistics were not used to
design the matrix. Although designed originally for air the
algorithm has proven to be highly reliable for dives using
oxygen-nitrogen-helium trimixes.
DCAP dates back to commercial diving in the 1960’s when
the search for offshore oil found commercial diving
companies doing heliox diving; up to that time only Navy
tables were available, and they did not meet all needs for
offshore diving. Dr. Heinz Schreiner led a development
team at Ocean Systems, Inc., in both computation and
laboratory validation of new heliox tables. This was done in
collaboration with others, some of whom were then the
leaders in decompression, including Bob Workman, Chris
Lambertsen, Val Hempleman, and Albert Bühlmann.
Schreiner’s computational methods were based on
Haldane’s concepts, and they relied heavily on feedback
from the field and other empirical information.
Following corporate changes at Ocean Systems, Inc. the
task was picked up by Dave Kenyon and Dr. Bill Hamilton
and they offered decompression services to others in the
field . From this, in about 1975 the need for a number of
different tables by a European client led to the idea for
Hamilton Research, Ltd., to provide a program to generate
decompression tables instead of just providing the tables
themselves. That is, to sell the goose instead of just the
