| I got this from CompuServe, a test that West Marine did with the Tinker
and comparing the lifeboat approach against the liferaft survival
philosopy:
Page 1
Copyright West Marine and Sea Star Yachting Products
West Marine/Sea Star Life Raft Test
Copyright West Marine and Sea Star Yachting Products
June 25, 1994
Sponsored by:
West Marine Products
Sea Star Yachting Products
Switlik Parachute Co.
Henshaw Inflatables, Ltd.
Introduction
This report documents a heavy weather test comparing the new Switlik
MD-2 yachtsmanUs life raft and the Tinker Traveller life boat. The test
was conducted on June 25, 1994 by West Marine Products, of Watsonville,
CA, and Sea Star Yachting Products of Alameda, CA.
Objectives
This test evaluated two distinctly different types of craft reflecting
two approaches to survival and rescue after abandoning ship. The
Switlik MD-2 life raft is a conventional type raft designed to be
stored for extended periods of time and inflated only during an abandon
ship emergency. It can be readied for boarding in less than a minute,
using conventional CO2/nitrogen inflation systems, and is packed with a
modest inventory of survival gear. It provides environmental protection
for up to six individuals. Due to its octagonal shape and lack of
propulsion and steering methods, it is not maneuverable.
The Tinker Traveller is a combination inflatable dinghy and survival
craft. In appearance, it is similar to an inflatable dinghy like those
made by Avon, Zodiac, and West Marine. It has a segmented plywood
floor, hard transom, and small dodger on the bow. It incorporates an
inflatable survival canopy which encloses the occupants to reduce
exposure. In addition, it is supplied with a compact sloop sailing rig
with a daggerboard and rudder. This rig, plus conventional oars, allow
the Tinker to be sailed or rowed reasonably well so that its crew might
be able to reach land or travel to shipping lanes where the chance of
rescue is greater.
Location
This test was conducted in the open ocean, in an area NW of the Golden
Gate of San Francisco Bay known as the Potato Patch Shoal. This area is
north of the main ship channel into San Francisco Bay which is on an
approximate course of 60!/240! magnetic. While the ship channel is
dredged to about 10 fathoms, the shoals to the north and south of this
channel are very rough due to the shallow depths of around 4 fathoms.
Waves frequently break during storm conditions, especially during an
ebb tide. Due to the strong currents and constricted entrance at the
Golden Gate, short wavelength and steep sided chop is abundant, along
with the longer Pacific swells. The characteristic "beaten egg white"
chop of the Golden Gate provided a remarkably tippy surface to test the
capsize resistance of the tested craft.
Weather
Typical summer conditions for this area prevailed during this test.
Winds at the 1000 PDT aunch time were from the NW at 20 knots (force
5). Over the course of the day, winds increased to a steady 25 knots
with frequent gusts above 30 knots (force 6-7). Waves were about four
feet at the start (sea state 3), building to 6-8 feet (sea state 4-5)
at 1400. Whitecaps were present all day long.
Support Vessels
The primary support vessel was a Garden 51 fiberglass ketch, Sea Star.
In addition, a Tinker 10' dinghy was used to ferry participants between
the life rafts and Sea Star.
Participants
Ray Thackeray provided his vessel Sea Star, the Tinkers, and three crew
members who helped to document the event on video and slide film. West
Marine provided six associates, most of whom had extensive offshore
sailing experience. Due to the rough conditions, it was not possible to
exchange crews as we had done in past tests. Ray Thackeray and Chuck
Hawley were the primary testers, with Scott Lonsway and Pepe Parsons
also spending time in the MD-2 raft.
Seasickness
Conditions were perfect for inducing motion sickness, and several crew
members on the large support vessel were affected by it. Both of our
liferaft testers became sufficiently nauseated to vomit. This was
associated with specific functions on board the rafts: orally inflating
the MD-2 floor, victim recovery from the water where water was
ingested, and projects requiring concentration inside the canopies.
Normal methods for reducing motion sickness were effective,
particularly getting outside the enclosures so that the visual
equilibrium was established.
Communications
A Navico Axis handheld VHF radio was used for communications between
the rafts and the support vessel . This worked well until it was
immersed. We believe that the presence of water in the microphone area
made the transmission excessively garbled, although the battery may
have run down at that point. A Standard Communications HX-230S was also
used in a protective vinyl bag, and it performed well. Since it has a
relatively large PTT button, the HX-230S was quite easy to operate.
Craft Tested
Below is a brief description of the craft tested:
Switlik MD-2
The Switlik MD-2 is a 6 person raft, meeting the ORC regulations for
offshore sailing races. It has two buoyancy tubes with a large
self-supported canopy. It is constructed of heat welded polyurethane
fabric and is octagonal in shape. It was supplied with Switlik's
optional inflatable floor. It was packed in the Switlik Cordura nylon
valise.
The MD-2 is the newest of Switlik's yachting life rafts, and it borrows
many design features from their other models. Some of these features
are as follows:
1. Materials: Urethane coated nylon fabric using heat welded
construction. The compressed gas inflation system is the same as those
used on USCG approved life rafts. The canopy is an orange outside/blue
inside material.
2. Stability: Ballast pockets are the same as those used in USCG
approved rafts. Octagonal shape for stability.
3. Access: Two large doors for greater versatility in ventilation
and visibility. Door closure via large marine grade zippers.
4. Price: Competitive with imported rafts with fewer features to
induce customers to buy true offshore life rafts rather than inshore or
coastal rafts.
Tinker Traveller
The Tinker Traveller is a dual purpose dinghy and life boat. Without
its sailing rig and canopy, it resembles a conventional 12' inflatable
sportboat. With its sailing rig in place, the Traveller can be sailed
reasonably well upwind and down. With the inflatable canopy in place,
the Traveller resembles a small covered wagon, with enough space for
two or three adults and some provisions. It can also be fitted with
manually operable CO2 inflation cylinders for rapid inflation of the
hull chambers. The hull fabric is a Hypalon/neoprene mixture, while
other components appear to be heat welded polyurethane/nylon fabric.
The Traveller is a six person dinghy, although is does not have enough
room for six as a life boat.
The Traveller features "hull within a hull" construction. Inflatable
inner portions of the main tubes provide reserve buoyancy should the
outer tubes become punctured. This capability was not tested.
The Tinker Lifeboat was designed after the Fastnet Race of 1979 in
which hundreds of boats were subjected to gale conditions, and 15
yachtsmen lost their lives. The requirements were as follows:
1. Stability: High capsize resistance through hull design and
drogue, keeping the lifeboat beam-on to the seas and wind.
2. Capsize: Easily righted from within, maintaining thermal
protection while inverted.
3. Navigation: Ability to maneuver towards rescue.
4. Comfort: Thermal insulation from ocean and air, ability to be
made dry inside, protection against "fish hits" from below.
5. Deployment: Ability to be kept ready for use on deck, or
inflated quickly using the hand pump or CO2 inflation.
6. Drills: Ability to practice Abandon Ship evolutions except for
CO2 inflation.
7. Durability: Ability to be used for many years as a working
dinghy in addition to life boat duties.
8. Cost: Competitive with high quality inflatable dinghies and
life rafts combined.
Comparison of Equipment/Construction/Specs
Switlik Tinker
MD-2 Traveller Life Boat
Price: $3,970.00 $5,361.00
Price (5 yrs, assuming re-packing): $5,320.00 $5,361.00
Shape: 8-sided Sportboat
Storage Cordura nylon valise PVC coated polyester valise
Tube diameter: 9 1/2S x 2 12S
Outside Dimensions: 7'0S x 7'0" 12'0" x 4'9"
Inside dimensions: 5'5" x 5'5" 10'5" x 1'8"1
Weight as Tested: 65 121
Main Tube Inflation CO2/Nitrogen Hand bellows/CO2 (opt.)
Canopy Inflation: Automatic/CO2 Hand bellows
Canopy Openings Two inverted V doors Two drawstring closures
Arch Tubes: One Self-supporting
Ladders: Two Over the bow boarding
Water: 96 oz. Opt.
Flares: 3 Hand/2 Parachute Opt.
Paddles: Yes 6' Jointed Oars
First aid kit: No Opt.
Repair Kit Yes Yes
Flashlight: Yes Opt.
Water act. lights: One Opt.
Sailing Rig No Yes, sloop rigged
Sailing Hardware No Mast, rudder, daggerboard, shrouds,
sails
Seat/transom No Central wooden thwart, transom
Drogue Yes Yes
ORC Specifications
One of the strongest motivators for equipping a yacht with a life raft
is that it is required if the boat is to participate in offshore races.
The Recommendations for Offshore Sailing, published in the US by the US
Sailing Association, describe in detail the attributes which a life
raft must have to be approved for use while racing. The following is
taken from Appendix II of the 1994 Special Regulations:
Switlik Tinker
Requirement MD-2 Traveller
1.a Stowage Yes Yes
1.b Only saving of life at sea Yes No
1.c Stable Yes Yes
1.d Canopy, highly visible, can collect rain Yes Yes2
1.e Painter, outer lifeline, inner lifeline Yes No3
1.f Capable of being righted by a single person if inverted.
Yes Yes
1.g Fitted at each opening with an efficient method to board
Yes No
1.h Buoyant and rugged valise Yes Yes
1.i Buoyancy divided into separate compartments Yes4 Yes
1.j.1 Capacity, based on buoyancy of tubes 6 6
1.j.2 Capacity, based on floor area 6 3
1.k Floor design Yes Yes
2.a Rescue quoit Yes No
2.b Knife and bailer Yes No
2.c Two sponges Yes No
2.d Sea anchor or drogue Yes Yes
2.e Two paddles Yes Yes
2.f Repair outfit Yes Yes
2.g Topping off pump Yes Yes
2.h Electric torch Yes No
2.i Three handheld flares Yes No
2.j Six sea sickness pills/person Yes No
2.k Waterproof survival instructions Yes Yes
2.l Non-toxic gas, auto inflation, able to be topped off Yes
Yes
Deployment/Inflation
Crew members Hawley and Thackeray simulated an abandon ship evolution
for each craft. An abandon ship bag was prepared in advance for each
raft. Due to the different design concept of each raft, a different
launch methods were used.
The MD-2 is a conventional raft which should only be deployed when it
is clear that the primary vessel is sinking, since it cannot be
re-used or stored after inflation. In fact, there is a chance of
damaging the raft if it is kept alongside a damaged vessel.
With the painter secured to the support vessel, the MD-2 was tossed to
leeward and its inflation line was pulled. The raft inflated quickly
(approximately 20 seconds), in the upright position, and with the
canopy doors in the down position. After the raft inflated, the over
pressure valves released excess gas causing the raft to "hiss" for
about four minutes. The testers lowered themselves through the canopy
door (with some difficulty owing to the rolling of the support vessel
and its high freeboard), accepted the prepared "grab bag" from one of
the support crew, and cut the painter free.
Deployment of the Traveller requires a different approach. It is stowed
on deck like an inflatable sportboat, with its sailing rig stored
separately in a 6' x 1' zippered duffel. As with the MD-2, a separate
grab bag was used to store the majority of the survival equipment. To
deploy the Traveller, its valise was removed, and it was unfolded on
the stern deck. One crewmember reached inside the transom and turned on
two valves which controlled the flow of CO2 to the right and left hull
tubes. The CO2 supplied was enough to inflate the hull tubes about half
way. Apparently, the soft nature of the boat makes it more stable
initially, since it effectively "sticks" to the water alongside the
mother vessel which reduces the chance that the raft will "skip away"
in high winds. The boat was put over the lifelines in this partially
inflated state. At this point, the sailing rig was slid inside the
deflated canopy so that it would be available for use after boarding.
The flaccid nature of the boat made launching without damage
challenging, since it sort of draped over the lifelines and stanchions.
Two scenarios would have made launching easier: the raft could have
been more fully inflated while on deck before launching, and launching
from the boat as it sank would have reduced the substantial freeboard.
Alternatively, the Traveller can be kept inflated on deck, as with any
inflatable dinghy. This would eliminate the need for the CO2 inflation
cylinders. Optionally, additional cylinders might be installed which
would inflate the life boat more fully. Henshaw believes that pressure
release valves are unreliable and expensive and has therefore elected
not to use them on the Traveller. This accounts for the partial
inflation with CO2 followed by topping off by hand.
Boarding
Switlik believes that life rafts should be as easy to board as
possible. To this end, their rafts are packed with the doors in the
canopies as open as possible. The MD-2 has two large triangular-shaped
doors which we found easy to enter.
The partially inflated Traveller was difficult to board, since it
filled with water from waves and the added weight of the two crew
members. The canopy was deflated, and lying on top of the sailing rig
duffel, which made it difficult to figure out where to sit.
Interestingly, the canopy covers the entire interior of the raft,
necessitating entering the canopy by crawling into the fore and aft
openings.
When the painter was cut free, one crewmember set to work bailing
about 8" of water out of the boat, while the other began to top off the
inflation chambers. This proved difficult due to three factors: the
valves were located several inches underwater, the pump was designed to
be used on a hard surface, and the inflation hose tended to kink if not
held in a smooth arc.
After approximately 10 minutes of steady manual inflation, the tubes
became firm to the touch, and the crew began to inflate the canopy.
Bailing continued via a dinghy style piston-type pump, which proved
tiring and ineffective. A standard scoop bailer would have worked
infinitely better, being faster and less tiring. Had the Traveller been
inflated firmly before launch, it would no doubt have remained drier
and would have been easier to board.
Drogue Deployment
Each craft was supplied with a conical drogue mesuring approximately
24" in diameter by 36" long. The MD-2's drogue was tethered to one
"end" of the raft, so that the doors face across the wind. The valise,
which was attached to the raft near the port side door, created
substantial drag which caused the raft to yaw about 45! away from the
wind. The attachment point of the drogue could be moved from side to
side along a section of one of the perimeter lifelines, allowing some
variation in drift orientation. It appeared that the attachment point
of the drogue to the raft would chafe over time, possibly causing
either the lifeline or drogue line to part.
The Traveller's drogue is deployed off the starboard beam, which
increases the stability of the raft in heavy conditions according to
tests run by the National Maritime Institute Limited. The drogue is
made from a brilliant orange mesh that is easy to see from rescue craft
due to its distinctive color. It uses a substantially longer rode of
approximately 75' as compared to the MD-2's 35'. The Traveller has a
length of plastic tubing to protect the line and the tube fabric where
the line passes over the inflation tube.
Both drogues would occasionally cavitate on the surface as large waves
hit the rafts. The Switlik drogue actually broke the surface several
times, although it rapidly sank back into the water. Neither appeared
unstable, and neither fouled. While we did not experiment with
different drogue line lengths, it would be interesting to compare the
rate of drift and the effect on comfort in the raft using different
line lengths. In our opinion, both drogues would benefit from
additional weighting.
Canopy Design
The Switlik MD-2 has a single canopy support tube which is placed
outboard of the upper inflation chamber. The height and location of the
canopy support creates sitting headroom for at least four of the
occupants: two at each end under the vertical portion of the tube. The
other two crew members would be adjacent to the door, and would have
headroom if the doors were open. As with other Switlik rafts, the
canopy is bright orange on the outside, and blue on the inside. The
blue color is intended to reduce motion sickness orange canopies often
seem to induce. The primary effect is to dramatically darken the
interior since the combination of the orange and blue colors
effectively block most of the light.
The two doors zip from bottom to top, allowing the crew members to
trade off freeboard for ventilation and visibility as conditions
dictate. There is no designated viewing port. Since the doors zip up,
there is a large variation in how much protection vs. ventilation is
available. In the conditions which we encountered, it was possible to
stand in the raft and grab the arch tube for stability, so that one's
height of eye and visibility was increased.
As expected, it was claustrophobic with both doors shut tightly, and
neither crew member desired to remain in that state for more than a
minute. Light streamed in through the stitching holes along the zipper
and it appeared that water might leak in, although none did during our
test. The 9 o'clock canopy door had a small rain collection tube,
although there was no trough for guiding the rain to the tube.
Fabric tape zipper pulls were located on the outside of the raft, with
only the standard zipper pulls on the inside. This seemed odd, since
the need is greatest on the inside of the raft.
The Traveller's canopy is made from a bright orange heat welded vinyl
fabric that has multiple lengthwise tubes. It is inflated using the
hand inflation pump, and forms a lengthwise arched tube which covers
the hull from the transom to the aft edge of the covered bow.
The Traveller 's canopy can be completely removed, or removed from one
side to open the raft to the elements, as when sailing. The ends of the
canopy serve as viewing and ventilation ports, and their openings can
be adjusted with the light line which is provided. To stand watch, it
is necessary to sit on the transom or forward on one of the tubes, as
the canopy effectively covers the entire interior of the boat.
The canopy is laced in place with light line using a chain stitch that
can be removed in less than a minute. It is far slower to install, but
can be done with the boat in the water. Normally the boat would be
stored with the canopy in place, so that it would only have to be
inflated to be ready for use. A system for compressed gas inflation of
the canopy is available as an option.
The thickness of the inflated canopy provides both insulation in cold
weather and flotation in the event of a capsize. Each end of the canopy
can be drawn down tightly with lines to seal the interior.
Headroom is limited, although there is enough if the occupants sit on
the Traveller's sole. If the sailing rig is fitted, the canopy can be
partially deflated and pulled back so that the mast has clearance.
The Traveller canopy can be partially deflated to form a rain water
collection pocket, and the sails make effective "catchers" as well.
Floor Design
The MD-2 was supplied with an optional inflatable floor, which is made
from a light heat welded fabric in two halves. These are inflated
orally using a tube similar to those found on inflatable lifejackets.
The "tufted" type floor used C-shaped welds to hold the floor in a more
or less even thickness. This was comfortable, but not as effective as
the drop-stitch floor of the Switlik Coastal raft we tested in 1991
which has a practically flat surface which did not collect water.
We managed to tear off one of the tie-down straps for the floor when we
re-boarded the raft from the water, but this did not puncture the air
chamber. It is not obvious why the floor is supplied in two halves, but
it does complicate the installation and leaves a seam in the center
which seems unnecessary.
The Traveller has a plywood floor glued into the fabric of the hull.
This makes it somewhat effective for insulation, and also makes it
difficult to lose items since there are no intermediate layers. It is
quite solid under foot. One area where the plywood floor is clearly
superior to inflatable floors is that many survivors have mentioned
"fish hits" where large fish (including sharks) have bumped against the
bottom of the raft's occupants, resulting in painful bruises.
Ease of Familiarization
Once the inflation lanyard/painter ion the MD-2 s pulled , there is
little need for further instructions (a good thing since there are
almost no instructions in evidence). The floor must be blown up and
attached, and the contents of the survival pack need to be inspected,
but for the most part the occupants are left to their own devices. The
survival pack is tied to the interior of the raft and is packed in
bright yellow fabric to make it easy to find. The knife is in the
standard location by one door, along with a water activated light. The
drogue was deployed by yanking it free and allowing it to stream
upwind. The knife was a collapsible design.
The Traveller was equally devoid of instructions, although anyone
familiar with assembling an inflatable sportboat or a sailing dinghy
should have no trouble during the day. At night we suspect that it
might be very difficult, since the boat needs to have its buoyancy
chambers topped off, be supplied with additional gear including the
sailing rig, have its canopy inflated, and be launched. This challenge
would be reduced if the boat were kept fully inflated.
If the Traveller is launched before the canopy is inflated, it becomes
challenging to complete the process since it is necessary to duck under
the unsupported canopy to find the pump, bailers, sailing rig, etc.
This proved very nauseating for at least one participant (but there
wasn't much during the day of testing that wasn't nauseating). It would
be very difficult to complete the process of readying the boat for
survival either on deck in the dark, or in the water in the dark.
One advantage, however, is that the Traveller can be inflated manually
and deflated any number of times before the actual emergency. In fact,
it is likely to be been used many times as a dinghy, so that the
location of valves and other equipment would be known to the users.
Also, depending on the safety orientation of the ship's crew, mock
drills could be carried out with the exception of the CO2 inflation
which would simulate the process of abandoning ship. While this is
possible with a life raft, it is impractical to actually inflate the
raft since it must be professionally re-packed each time, and repeated
inflation has a tendency to gradually weaken the fabric.
Air Holding Ability/Ease of Repair
The MD-2 has the traditional stacked independent buoyancy tubes. The
canopy arch tube is an integral part of the upper tube. In other
words, if the upper tube is violated, the arch tube deflates. Other
rafts have a one-way valve connecting the arch tube to the upper
buoyancy tube so that the arch tube remains inflated separately.
The urethane based MD-2 fabric is light and strong, and is unlikely to
be punctured except at the time of launching. It comes with several
clamp-type leak stoppers in its equipment bag. No air loss was noticed
during the test.
The Traveller uses a heavier Hypalon/neoprene fabric as befits an
inflatable dinghy which might be used on beaches and other rough
surfaces. Its patch kit consists of a container with patches, glue, and
sandpaper. While not tested, this is probably more suitable to
land-based repairs, and would be difficult to use at sea. The twin
chambers of each side of the Traveller provide redundant air holding if
one tube is somehow damaged. No air loss was noticed during the test.
Survival Kits
The survival kits packed in most liferafts, as has been documented in
numerous articles on survival in the past, are meager in their
contents. Depending on the degree of completeness supplied by the
manufacturer, and purchased by the customer, life rafts may or may not
contain water, flares, fishing kits, first aid kits, repair kits, etc.
Life raft buyers are extremely resistant to paying for more complete
kits when buying the raft; however at sea, they believe that every kit
is woefully inadequate.
Every life raft owner should know what his/her raft contains. If
unknown, it should be documented at the raftUs next repack. No one, in
our opinion, should rely solely on the equipment supplied in even the
highest specification life raft, but should rather augment it with a
separate kit.
This separate kit, often referred to as an Abandon Ship Bag, should
contain an EPIRB, a water maker, and additional SOLAS-grade flares at a
minimum. Although these items can be packed within the raft, there are
numerous stories of needing these items without needing to launch the
raft. Therefore, we believe that they should be in the raft only if
there are similar items carried on board outside of the raft.
Personal Volume/Floor Space
The MD-2 meets Ocean Racing Council specifications, which require 4 sq.
ft. per person, and minimum equipment inventories. We only attempted to
put four men inside, and while crowded, it was not horribly cramped.
The octagonal shape provides fewer places to get out of each other's
way, compared to the oval shape of the Switlik Coastal. he use of a
vertical canopy arch tube, which is set outboard of the upper tube,
provided excellent headroom reminiscent of the Plastimo Offshore raft
we found most comfortable in our last test.
The Traveller's interior beam is only about 20" across. Since the
canopy attaches to the center of the top of each hull tube, it is
possible for three persons to sit on top of the buoyancy tubes on each
side, with one's head bowed toward the center and with one's knees
against those on the opposite side. With only two aboard, the
Traveller's space seemed cramped but adequate. Three or more would have
been pretty horrible. The daggerboard trunk/thwart and the bow dodger
take up a lot of interior space that might be used for reclining,
although one's legs can be extended underneath both items if seated on
the floor. If the person on watch were to sit forward, while the person
asleep were to lie aft, it might be possible to rest on board.
In general, the Traveller felt too small to spend an appreciable time
aboard, and it would benefit by being taller and beamier before we
would consider it comfortable at sea.
The ORC regulations require 4 sq. ft. of floor area per person, which
the MD-2 achieves with its 24 sq. ft. The Traveller has 15.75 sq. ft.,
so it barely misses the requirement for a four person life raft.
Capsize Resistance and Righting
An important part of the test was to purposely capsize the rafts and
then attempt to right them and re-board them. While we purposely held
the test in rough conditions, neither raft felt unstable when inflated,
bailed, and with the drogue deployed.
We tried to establish the relative capsize resistance by loading the
rafts with all the weight on one side. In the case of the MD-2, two
crewmembers sat in the starboard side gunwale, which caused the port
side to lift rapidly. It took a short time for the water to drain from
the ballast pockets, whereupon a wave hit the raft and it capsized
quickly. Observers reported that the pockets appeared to be 1/3 full of
water, at most, at the time of capsize, although the raft had been
deployed for 30 minutes or so. We were frankly surprised at how easy it
was to capsize the raft.
The raft floated at about a 135! angle of inclination, supported by the
arch tube. One crewman was able to climb aboard the overturned raft,
pull the righting strap free of its snaps, and pull the raft over
easily.
Both crew members boarded without assistance through the doors by means
of the webbing ladders. Like all such ladders, they tended to swing
under the raft and it took several tries to use the ladder correctly.
At night it was felt that the ladders would have been hard to find and
use, particularly if the victim were hypothermic.
The MD-2 was capsized a second time to check our observations. In this
case, the raft was capsized with three persons on board, and it was
only necessary to get them on one side of the raft to initiate the
capsize. Righting was accomplished by reaching up to the webbing and
pulling the raft over while still in the water.
When righted, the MD-2 had 40 gallons of water inside after the first
capsize, and perhaps 10 gallons after the second capsize. The
difference was due to the method of righting. Since we did not stand on
the raft during the second righting, there seemed to be less chance of
scooping water as it came over.
To find out why the MD-2 capsized reasonably easily, we examined the
ballast bags while the raft was upright. Even though ballasted with
chain, the bags tended to collapse and not hold their "bread box"
shape. We are of the opinion that stiff stainless steel wire or the
equivalent might be used to force the bags into the shape resulting in
the maximum volume.
The Traveller was capsized twice with the canopy in place. Since there
are no openings athartships, the two crewmembers had to lean against
the inside of canopy, opposite of the drogue. The life boat rolled
reluctantly, and the crew ended up lying inside the inflatable canopy.
This attitude could have been maintained for some time without
discomfort; in fact, the Traveller was arguably more comfortable upside
down than right side up.
To right the Traveller, the crew simply rolled their bodies in the
opposite direction, which caused the boat to resume its upright
position. The boat was practically dry when righted, with only a gallon
or so left in the hull. This proved to be a much more efficient method
of bailing than the pump.
We also tried to use the catamaran righting method of using a line on
the high side of the boat (in this case the drogue rode) to pull the
boat over. This worked well. Crew members in the water could either
slide inside the canopy, or right the boat from the outside. If they
elected to use the "inside" method, they would avoid the need to
re-board the raft over the bow.
Ease of Crew Recovery
Most yachtsman's rafts are equipped with a throwing quoit and line to
assist in making contact with a person in the water. We threw the MD-2
quoit (the Traveller was not so equipped) using a variety of different
techniques, and were able to throw it about 25-40 feet. The weighted
rubber ring was effective against the wind as well as downwind.
To simulate the recovery of a disabled crew member, one person in the
water was pulled aboard by a crewman in the raft. We used a surf
rescue technique where the victim faces away from the raft, and the
rescuer lifts the victim' by the armpits while falling backwards into
the raft. This worked reasonably well , although we were of equal size
and not hypothermic. We did not attempt to deflate the MD-2 top tube to
lower the freeboard, which is apparently a technique that can be used
to make the process easier for rescuers who are of smaller stature.
The method for the Traveller is somewhat different: the low bow area is
used as a boarding ramp, and the reduced buoyancy there makes for much
lower freeboard. This reduced freeboard made recovering the person in
the water much easier.
Water Shipped at Sea/Bailing
The MD-2 was almost entirely dry when initially inflated, and took on
water only as wet crew members climbed in and out, and as it was
righted after capsize. The high sides of the raft seemed unlikely to
allow water in except when struck by breaking waves. The whitecaps that
were prevalent during our trails did not cause water to come aboard.
Once it had been bailed dry initially, the Traveller remained dry as
well . Some water leaked in through the grommets in the dodger where
the sailing control lines passed through the fabric. In severe
conditions, it is possible that water might leak under the canopy along
the top of each buoyancy tube, but we did not notice any during the
test.
Once again, a bailer with a flat bottom would have been far superior to
the dinghy-style piston pump we used.
Rate of Drift/Maneuverability/Sailability
While it was difficult to determine the rate of drift of the rafts with
any certaintly due to the strong currents in the vicinity of the test,
we estimate that, in 25 knots of wind, the rafts drifted at about one
knot.
The MD-2's drift rate could have been increased by retrieving the
drogue and/or collapsing the ballast pockets with a line under the
raft. Otherwise, it was not obvious how to affect its course.
While testing the stability of the Tinker, a large container ship was
noted approaching the ship channel, and about four miles to seaward.
Judging this to be an opportune time to get out of the ship channel, we
elected to erect the sailing rig immediately.
The Traveller 's sailing rig consists of a three-piece jointed mast,
shrouds with adjusters, boom, two sails, and some running rigging. The
kit also includes a kick-up rudder and a daggerboard. After striking
the canopy, the crew of two were able to assemble the sailing rig in
about 10 minutes. With about 20 knots of wind, only the jib was used,
and it propelled the boat at 3-4 knots. There was some trouble with the
kick-up rudder, but that was remedied and the boat remained under
control. Total distance sailed was probably four miles in very rough
water.
The sailing kit, while effective, consists of numerous small items, the
loss of any one of which would have rendered the sailing rig
inoperable. For example, the shackles were the loose pin type. The mast
sections were not joined with shock cord like tent poles. Because this
was also the first time that the rig had been stepped, we would
anticipate that tricks could be employed by an experienced crew to make
it easier in successive attempts.
This is really where the two craft differed the most: the MD-2 is
designed to be a stable, practically immobile, survival platform in
which the occupants can safely wait for rescue, assuming the rescue
agencies have been alerted due to an EPIRB signal or visual sighting.
The Traveller provides the option of sailing to a place where a rescue
is more likely, or conceivably to land. Several accounts exist of
survival in Tinker dinghies where the crew has been able to sail to a
higher traffic area and be rescued.
Conclusions
Nearly all boaters who travel out of sight of land should have some
sort of survival raft in our opinion. The numerous documented cases of
vessels sinking, due to known causes or unknown, and the short time
that a person can survive without protection makes life rafts a
necessary part of offshore survival gear.
The craft tested in this test represent two of the best examples of
their type: a stable, commodious, unmaneuverable life raft capable of
sheltering six occupants; and a multipurpose, maneuverable life boat
that can hold five as a dinghy, and 2-3 as a life boat. The Traveller
proved that is indeed sailable, and stable, under our test conditions.
We have summarized our conclusions by listing the outstanding features
and shortcomings of each type of craft tested. Note that these comments
are specifically aimed at the craft tested: there are life rafts and
dinghies which are far worse than our samples, and which may have
additional shortcomings.
Life Raft Advantages:
1. Life raft contains minimum survival inventory even without
additional gear bag.
2. Rapid deployment technique does not require much practice
technique. Most life rafts are identical in operation, and require only
general familiarization.
3. Optional "automatic" hydrostatic deployment available
4. Reasonable area per person when loaded to capacity. Good
headroom.
5. High stability when loaded evenly.
6. Good environmental protection.
7. Large search target.
8. Rugged construction and reliability5
9. High freeboard reduces water shipped in heavy seas.
Life Raft Disadvantages:
1. If capsized, occupants will likely have to right it from the
outside, exposing them to heat loss.
2. High freeboard makes it difficult to board from the water.
3. Stability of the raft depends on the use of a drogue; if the
drogue is lost, the raft is more likely to capsize.
4. Annual re-packing expense expected to cost $200 over the life
of the raft. Risk of deterioration if raft is not re-packed, and
possible deterioration between repack dates.
5. Single floor life rafts promote heat loss and are very
uncomfortable in cold water
6. Maneuverability, even using paddles, is practically nil.
7. Canopy deterioration has been reported which makes collected
water unpalatable.
8. Inability to practice MOB drills without re-packing raft.
Life Boat Advantages:
1. Can be sailed or rowed to land or to somewhere where the chance
of rescue is increased.
2. Multiple opportunities to collect rain water, using sails or
canopy, which will have less tendency to pollute the water.
3. Boarding is relatively easy over the bow.
4. Canopy provides buoyancy when inverted, and hypothermia
protection when upright and inverted.
5. Can be righted from inside the craft, with less heat loss.
6. Heavy construction using Hypalon fabric.
7. Wooden floor protects against fish impacts.
8. Wooden floor offers some hypothermia protection and cannot
deflate with a loss of properties.
9. Redundant air holding in each "side" of the boat.
10. Opportunity for Abandon Ship Drills due to re-packable design.
11. No annual maintenance.
Life Boat Disadvantages:
1. Low freeboard makes water intrusion more likely.
2. Less comfortable, especially when loaded with more than two or
three individuals.
3. Does not meet ORC size specifications for more than 3 persons,
and fails ORC standards in many areas.
4. Weight of complete craft is heavier than many cruisers will be
able to launch easily.
5. More owner responsibility in making sure that craft is ready
for use at sea6
6. More incremental processes prior to launch.
7. Color of canopy is nauseating while inside during the day.
8. Likelihood of launching boat with substantial water aboard if
not done correctly.
PARTICIPANTS:
Sea Star
Capt. Ray Thackeray, Sea Star Yachting Products, Skipper and "Victim"
Amy Ewing, Masterworks, Documentation
Tim Schaaf, Masterworks, Video crew
Dan Spradlin, Deckhand
Chuck Hawley, West Marine, "Victim"
Paul "Pepe" Parsons, West Marine, Deckhand
Howard Wright, West Marine, Helmsman
Scott Lonsway, West Marine, Photographer
Chris Smith, West Marine, Deckhand
Linda Day, West Marine, Deckhand
Vendors:
Switlik Parachute Company, Trenton, NJ
Henshaw Inflatables Limited, Somerset, England
Navico Navigation and Communications Systems
FOOTNOTES:
1 The bow dodger of the Traveller covers an area approximately 2
feet in length, which could be used for storage or leg room. It is a
wedge-shaped area which tapers towards the bow.
2 While the Traveller canopy can collect rain, the rules require
that "means shall be provided for collecting rain". It is not obvious
if this has to be a special apparatus, or whether a method is
sufficient.
3 The Traveller has an outer lifeline along about 60% of its
length and no interior lifeline.
4 With stacked tube rafts, the floor is left unsuppoted if the
bottom tube deflates, while the canopy is unsupported if the upper tube
deflates and the arch tube is not independent.
5 This is primarily an attribute of Switlik rafts which use
polyurethane coated nylon and heat welded seams. Other rafts employ
different fabrics, which may not have the same properties. Other
manufacturers also seal the raft in a vacuum bag to protect it against
the elements.
6 This is arguably an advantage, and is consistent with the life
boat "participatory" survival philosophy.
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