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An early CG study, in 1985, concluded that a non-certified boat was 5 times more likely to be involved in a b
ing accident than a certified boat.
A newer, joint CG/NMMA study in 2005 concluded that a non-certified boat was 7 times more likely to be re-
called than a certified boat.
What Certification is Not
As good as it is, the NMMA Certification program isn’t everything to everybody. Some of the items that we d
certify:
Boat designs
Quality; As an old friend Tom Hale used to say, “a boat that doesn’t float can still be built to ABYC stan-
dards and still be certified.”
Standards not in the program.
The structural components of a boat. There are no ABYC scantlings standards – yet!
Old or used boats – God created surveyors to do that.
Market evaluations - See above
Marine engines
Sound testing
Other NMMA Services and Programs
To go along with certifying boats, NMMA also offers a variety of products including
boat capacity plates, various warning labels, safety brochures and generic owner’s
manuals. Each of these products is provided to both members and non-members on a
non-required basis for a nominal charge.
Summary
NMMA Boat and Yacht Certification continues to provide a valuable service to both boat builders and consu
ers. The program is just one piece in the puzzle of providing safe and fun boating. Isn’t that what boating is
about?
Stability No. to be ≥ 1.0
Stability factor to be ≥ 19 knots
This boat has acceptable stability in regard to its rig as the
Stability Number is greater than 1.0. At the same time, the
Bruce number is reasonably high. This indicates an accept-
able offshore cruiser, with a good turn of speed for a cata-
maran. If the hulls are long and slender at the waterline, this
boat can achieve very high speeds safely.
The Stability Factor is also over 19 knots, indicating again
that the rig is acceptable for offshore cruising use, with re-
gard to stability.
Note the formulas assume low angles
of heel, under 9 degrees, which applies
quite well to essentially all catamarans
that don’t fly a hull and
to most trimarans that
don’t fly a hull. A few trimarans may sail
in heavy air at over 9 degrees without flyi
the vaka out of the water. In this case the “beam” in all t
multihull stability formulas above should be replace with:
“Beam x cos heel angle, in expected sailing trim.”
In most instances; however, the heel angle will be under
degrees and the difference is then 1% or less--too small t
be worth calculating.
Note that many unlimited offshore racing multihulls have
Stability Numbers lower than 1.0. These craft can be exc
tionally fast, but they are not safe for offshore cruising. T
was clearly demonstrated in a recent Round Britain Race
where all but two of the unlimited-60 tris competing eith
capsized or had catastrophic structural failures.
1.45 RPI
Stability No. =
= 1.04
1.39 Bruce
Know It All Contest Solution
- continued from page 6
0.5 x 26 ft. Beam x 13, 440 lb.
Stability Factor = 8.24
= 19.1 knots
1, 100 sq.ft. x 29.4 ft. CE
231 S. LaSalle Street
Suite 2050
Chicago, IL 60604
Tel: (312) 946-6200
Web:
www.nmma.org