On Jun 11, 11:58*am, wrote:

Also IIRC most liferafts have a weak link in the teather that should
remain attached to the vessel, unless it sinks in which case the link
will fail allowing the raft to float free.

Fred

My Dearest Fred:
Since I know you are vastly more experinced and knowldegable my self I
though I would paste some info for you regarding lifraft Painter/weak
link/hydro static release. I konw you will read this carfully so you
do not shame yourself again.

By the way, as I am not that knowing what is "iirc?"
Bob

"....NVIC 4-8628 MAR 1986NAVIGATION AND VESSEL INSPECTION CIRCULAR NO.
4 86Electronic Version for Distribution Via the World Wide WebSubj:
HYDRAULIC RELEASE UNITS FOR LIFERAFTS, LIFE FLOATS, AND
BUOYANTAPPARATUS, AND ALTERNATE FLOAT-FREE ARRANGEMENTS1.PURPOSE. This
Circular summarizes the requirements for installing, testing, and
maintainingCoast Guard approved hydraulic release units used with
liferafts, life floats, and buoyantapparatus. Alternate float-free
arrangements not requiring hydraulic releases are also discussed.
2.DIRECTIVES AFFECTED. Navigation and Vessel Inspection Circular 7-69
is canceled, alongwith Changes 1, 2, and 3.3.DISCUSSION.a.General
Description. Hydraulic release units (also referred to as hydrostatic
release unitsor HRUs) are mechanical devices used as -links in the
lashings securing liferafts, life floatsor buoyant apparatus to the
deck of a vessel. If a vessel sinks before the crew canmanually launch
the equipment, the pressure of the water operating on the
HRUautomatically separates it into two parts. This action, at a depth
of between 5 and 15 feet,disconnects the lashing and permits the
unrestrained liferaft, life float or buoyantapparatus to rise to the
surface by its own buoyancy.b.Alternate Float-Free Arrangements. An
HRU is not necessary for satisfactory float-freeinstallation of an
inflatable liferaft, life float, or buoyant apparatus. Enclosure (1)
showsthe installation of a float-free inflatable liferaft in a crib
made of removable loose-fittingstanchions and bars. The height of the
enclosing stanchions will depend on the location ofthe raft on deck
and its exposure to boarding seas. Enclosure (2) shows a stowage rack
ingimbals for preventing a liferaft from being trapped if the vessel
should capsize as it sinks.Apart from the details of the stowage rack,
its location on deck must receive carefulconsideration, especially on
vessels with low freeboards where green water washing overthe deck
could result in the loss of the raft.c.Navy/Coast Guard HRUs. The
first Coast Guard approved HURs evolved from designsmanufactured to a
U.S. Navy specification, MIL-R-15041. Three of these stamped-
metaldevices received approval, although the "Arrow" unit is no longer
in production. Enclosure(3) includes details of these first HRUs, a
table of their operating features, and details ofthe gripes for
restraining the lifesaving device.(1)The Raftgo Model C is produced by
Raftgo Hendry Co. (formerly C.J. HendryCo.) under Coast Guard approval
numbers 160.062/1/0 through 160.062/1/4.Raftgo Model C releases may be
used to secure a single liferaft, life float, orbuoyant apparatus, or
multiple devices.
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Page 2
Enclosure (1) to NVIC 4-861(2)The Arrow Model 404 was produced by
Arrow Manufacturing Co. under CoastGuard approvals 160.062/210 and
160.062/2/1. The Switlik Model S-880 isessentially identical to the
Arrow HRU, and is produced by Switlik Parachute Co.under approval
number 160.062/3/0. Although these units are marked for acapacity of
up to 3750 lbs., the gripe spring arrangement will deform under
abuoyant load of around 1000 lbs. Therefore, Arrow and Switlik
releases areapproved for single unit installation only. They must not
be used to secure morethan one liferaft, life float, or buoyant
apparatus, or the buoyant load may deformthe gripe spring
arrangement.d.Painter-Securing HRUs. In Europe, painter-securing HRUs
perform the three-part functionof (1) a full-strength securing point
for the inboard end of the sea painter; (2) anattachment point for the
float-free weak link on the same end of the sea painter; and (3)
arelease point for one end of the strap restraining the lifesaving
equipment. In contrast, theNavy/Coast Guard style devices shown on
Enclosure (3) perform only the third of thesethree functions.
Enclosure (4) shows how the painter-securing HRUs differ from theNavy/
Coast Guard type. Unproved versions of these devices are available in
the U.S. foruninspected vessels, and there may soon be Coast Guard
approved versions that can beused on inspected vessels...."