A Skipper's Guide to Fishing Vessel Stability &
Modifications
© Copyright 1991 - 2003
Jensen Maritime Consultants, Inc. All Rights Reserved.
Photo courtesy Kelly Roupe
- Contributors (In alphabetical order) -
David L. Green, P.E., Senior Consultant
Jonathan G. Parrott, P.E., Director of Engineering
Craig A. Pomeroy, P.E.
This information has
been produced as a courtesy to the fishing industry and is free to all.
Distribution by others requires that the copyright shown above is clearly shown
on all copies. Additional copies are also available from Jensen Maritime
Consultants, but a nominal fee will be charged for large orders to cover
reproduction. Republication must have the prior written consent of Jensen
Maritime Consultants, Inc..
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I. |
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II. |
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III. |
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IV. |
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V. |
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VI. |
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VII. |
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VIII. |
A. Casualties
Commercial fishing is one
of the most dangerous occupations with over ninety deaths each year. While
statistics vary from year to year, the numbers from 1996 remain typical - one
hundred thirty six (136)
According
to the U.S Department of Health and Human Services publication "Commercial
Fishing Fatalities in
It is important to
understand the term "stability related". At least 75% - 80% of
"stability related" sinkings are caused by
either overloading, or flooding through deteriorated systems or boundaries,
non-tight closures, or other openings added for operational convenience. These
events impair or invalidate the designed stability characteristics of an
otherwise seaworthy vessel. The remaining vessel losses are for unknown
reasons, as there were no survivors, and combinations of weather, icing, or
initial loading can be suspected but not clearly defined.
Obsolete stability guidance
is another factor with the potential to increase stability-related risks. All
vessels experience weight growth over time, and a good rule of thumb is to have
a naval architect review stability every five years,
or when vessel modifications are made. Undocumented changes are especially
dangerous since the vessel crew may not be aware that the stability guidance is
obsolete. Modifications affecting stability include any weight changes,
watertight bulkhead alterations, tank boundary changes, fishing method changes,
freeing port alterations, lifting gear changes, windage
changes, ventilation terminal changes, bilge keel area changes, and repowering.
While the risks are high,
so can be the profits. The fisherman must weigh the risks of his occupation
against the benefits. Many losses result from deferring maintenance of
watertight & weathertight closures, or the lure
of potential profit overcoming common sense, such as pulling an overloaded net
on deck, or returning to port with holds plugged and fish on deck.
B. History of Stability
Criteria
The current arsenal of
stability criterias go far beyond the original IMO
standard. The Naval Architect can now determine the effect of wind & waves,
lifting devices, towing nets, water on deck, etc.. The
revolution in the computer industry has made stability analysis much faster and
more detailed, with some programs simple enough to be used by the Master on
board his own boat. Stability criteria are continuing to develop as more data
is added to the pool of knowledge each year. It is important to understand,
however, that no stability criteria can make up for poor seamanship or improper
loading. The Master is still the one that decides whether it is safe to pull up
that last net, or stack that next tier of pots.
C. Responsibilities of
the Master
The Master is responsible
at all times to ensure the stability and safety of his vessel. A qualified
Naval Architect can supply him with the necessary information to accurately
determine the stability of his vessel under normal operating conditions. He can
also supply a method of determining stability under unusual circumstances. He
cannot, however, stand over the Master's shoulder and force him to follow the stability
recommendations. The Master must understand basic stability concepts, be
familiar with his stability booklet, and use every means at his disposal to
ensure that the stability of his vessel is adequate to meet the sea and weather
conditions encountered. It is also paramount that the Master ensure that proper
vessel maintenance and repair is carried out, including maintaining the hull
and systems watertight & weathertight consistent
with the stability criteria.
A. Discussion of
Righting Arms & Metacentric Height
In common terminology, a
stiff boat (with at quick roll) has high initial (upright) stability. A vessel
with a slow roll generally has lower initial stability. It must be remembered
that initial stability has little bearing on the ability of a vessel to right
itself at larger heel angles. A very stiff boat may have poor stability at high
heel angles, while a boat with low initial stability may have excellent stability
at the higher heel angles.
Righting arms are a measure
of reserve buoyancy, or how much watertight structure is available to provide
buoyancy above the waterline. As a vessel heels to one side, the center of
buoyancy shifts outboard in the direction of the heel. The horizontal distance
from the center of gravity (G) outboard to a vertical line through the center
of buoyancy (B) is the righting arm (GZ) (see figure 1). As the vessel
continues to heel the righting arm will increase until the deck edge immerses.
Heeling further past this point, the center of buoyancy stops shifting
outboard, and the vertical line through the center of buoyancy becomes closer
to the center of gravity reducing the righting arm. Eventually the center of
buoyancy and the center of gravity will line up and the righting arm becomes
zero. The area under the righting arm curve up to a given angle is a measure of
the energy required to heel the vessel up to that angle. The area from a given
angle to the angle of zero righting arm is the
vessel's reserve buoyancy. The maximum peak of the righting arm curve
represents the maximum return-to-center force the vessel can exert.
As shown in figure 1, the
intersection of the vertical line through the center of buoyancy (B) and the
centerline of the boat is called the metacenter (M).
Since the metacenter shifts with heel angle, the term
metacentric height "GM" (the distance from
G to M) is defined only at very small heel angles. Hence the metacentric height is only a measure of the initial stability
of a vessel.
B. Available Criteria
The stability criterias currently available are based on stability in
calm water with sufficient safety margins to cover the dynamic conditions of
heavy seas. Over time, this has proved to be a successful approach. Very few
vessels that meet the two basic criterias described
below are lost due to stability problems.
The most widely applied
stability criteria in use today is Torremolino's
criteria, which sets forth minimum values for the initial metacentric
height (GM) and the righting arm (GZ) curve for a vessel (ref 46 CFR 28.570):
1.
GM at least 1.15 ft
2. GZ max at least 0.656 feet at 30 degrees or greater heel
3. Area 0 - 30 degrees at least 10.34 ft-deg
4. Area 0 - 40 degrees (or flooding angle) at least
16.92 ft-deg
5. Area 30 - 40 degrees (or flooding angle) at least 5.64 ft-deg
6. Angle at GZ peak = 25 degrees or greater.
7. Range of positive GZ =60 degrees or greater.
An
alternate criteria
originally developed for offshore supply vessels is also widely used (ref 46
CFR 170.173c). This criteria is useful for vessels
that have difficulty meeting Torremolino criterias 6 & 7:
1.
GM at least 1.15 ft 2. Area 0 - Peak at least 10.34+0.187*(30-Peak Angle)
3. Area 0 - 40 degrees (or flooding angle) at least 16.92
ft-deg
4. Area 30 - 40 degrees (or flooding angle) at least 5.64 ft-deg
5. Angle at GZ peak = 15 - 30 degrees
6. Range of positive GZ = 50 degrees or greater.
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M = Metacenter |
K = Keel |
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G = Center of Gravity |
GZ = Righting Arm |
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B = |
GM = Metacentric Height |
Figure 1
In addition to one of these
basic criterias, others are applied which take into
account service conditions:
- "Severe Wind and Rolling" (SWR) criteria
subjects the vessel to a blast of wind, and limits the vessel to 14
degrees of induced heel and specified righting energy ratios (ref 46 CFR
28.575).
- "Wind Heel" criteria places minimum limits on
the metacentric height (GM) based on wind
profile area (ref 46 CFR 170.170).
- Vessels involved in towing should meet the
"Towline Pull" criteria which places minimum limits on the metacentric height (GM) based on power, freeboard,
towline height above propellers, etc. (ref 46 CFR 173.095).
- Vessels engaged in crane lifting operations at sea
should meet "Lifting" criteria which limits the resulting heel
to 10 degrees and the area between the righting arm and heeling arm to a
minimum of 15 ft-deg up to a specified angle (ref 46 CFR 28.545 &
173.005).
- Vessels with large open decks which ship high volumes
of water should meet "Water on Deck" criteria (ref 46 CFR
28.565).
C. Selection of Criteria
For
Your Naval Architect should
select the appropriate criterias based upon vessel
size and service to ensure compliance with effective regulations, as well as
fundamental safety considerations.
D. Flooding &
Watertight Integrity
As shown in section B
above, the righting arm curve (GZ) is assumed to terminate when flooding occurs
through open vents, unchecked tank airpipes, etc.. Such openings can significantly restrict the vessel's
operation and carrying capacity. Your Naval Architect may recommend
modifications to openings, such as adding manual or automatic closures to
increase the usable righting energy.
It is extremely important
to maintain reserve buoyancy above the main deck, because it creates the forces
that right the vessel at higher roll angles. When rolling in a seaway, an open
porthole, vent, or door can allow water to enter on each roll. A vessel may
capsize if too much water enters, either by excessive free surface, or loss of
freeboard.
III. The
Stability Test (Incline Experiment)
A. Preparation
A stability test is a
scientific experiment designed to gather the data required to determine the
weight and center of gravity of a vessel. As such the vessel operator must set
aside dedicated time to conduct the experiment when no work is being done and
no crew is on board.
Your Naval Architect will
require certain technical information prior to the test. This includes an
Arrangement Drawing and a Lines Plan. If a lines plan is not available, the
boat must be hauled out of the water and measured.
You will also need to
supply a set of incline weights (usually concrete blocks) and a crane to move
them. The weights should be weighed on a certified scale prior to the test. Your
Naval Architect will tell you how much weight you will need. Incline weights
are available from most shipyards, or "ecology blocks" may be
purchased from concrete suppliers at minimal cost. Since concrete blocks absorb
rain water, they should be covered between the weighing and the stability test.
During an incline test,
long pendulums are read which accurately measure the heel angle caused by the
movement of the incline weights. Adverse weather conditions may be cause for
postponement of the test since wind & waves may make pendulum reading
impossible. Icing is also cause for postponement since the ice buildup will
increase the weight and raise the vessel's center of gravity. If ice is
present, it must be removed prior to the test.
On vessels with chines, the chine should be immersed at the transom during
the test. This is because the waterplane changes
dramatically with small heel angles on boats with fairly flat bottoms aft. This
change in the waterplane may throw off the results
and require a re-test.
The vessel must be free to
move during the experiment. There must be adequate water depth to ensure that
the boat does not come aground. If there are tides in the area where the test
is to be conducted, the incline may need to be scheduled during high tide. No
other boats should be rafted to the boat being tested, and all mooring lines
should be loose.
All large or wide tanks
should be either completely empty or completely full. Small narrow tanks may be
slack. Any cross connected tank pairs should have the cross connect closed. Sea
water holds should be empty. Your Naval Architect will consult with you in
advance of the test to determine what the tankage
should be during the test. For Load Line incline tests, all tanks must have a
visual means of verifying the liquid level, either by having the tank manholes
off, using sight glasses, or overflowing the tank vent. Tankage
should be arranged such that trim is minimized and list less than 1/2 degree.
Any gear and equipment
which does not belong with the boat should be removed or weighed. Foodstuffs,
pots & pans, ship's books, charts, linens, spare parts, fishing gear,
crew's effects, etc. which are part of a vessel's normal inventory may remain
on board, but will need to be weighed if they are out of position. For Load
Line stability tests, all weight except inventoried engine spares, life saving
gear, dishes & galley equipment, and ship's books & charts must be
accounted for either by removal or weighing.
Bilge water should be
minimal (bilges should be dry for Load Line stability tests). If this is a
problem they should be sucked out prior to the test.
Pendulums are usually hung
in one or more holds, usually in the locations that give the longest pendulum
lengths. Your Naval Architect will tell you where. The hatch covers need to be
removed in those locations. You will need to supply two lengths of lumber (2 x
4s) long enough to span the hatch at each pendulum position.
B. Running the Test
There are nine basic steps
that your Naval Architect will perform during the test:
1. Skipper Conference -
Discussion of vessel condition (tanks & deadweight) and operation (fuel burnoff sequence, hold loading sequence, fishing equipment,
etc.)
2. Pendulum Setup -
Pendulums will be set up in positions that are sheltered from the wind and
yield the longest pendulum lengths. This is normally in holds with the
pendulums suspended from one or more deck levels above. A board is typically
placed across a hatch opening from which the pendulums are hung. In the hold
bottom a marking board is placed transversely on sawhorses. The pendulum bobs
are weighted X shaped vanes that are submerged in buckets of water or oil for
motion damping. For Load Line tests, the three pendulums are ideally set up in
different locations and the damping fluid is oil. Each pendulum is measured to
determine its length.
3. Weight Placement - The
inclining weights are normally placed on the widest portion of open deck
available, either at the rail or near centerline. Weights are normally
staggered so that each weight can be moved all the way across the deck to the
other rail. The block positions are marked on deck so that movement distances
can be measured.
4. Deadweight Survey - Your
Naval Architect will inspect all spaces in the vessel for deadweight and
prepare a list of weights and locations. For large vessels where the deadweight
survey is lengthy it may be performed the day before the test. All spaces must
be unlocked.
5. Tank Survey - The levels
in all tanks will be determined by visual inspection. This is usually
accomplished by reading sight gauges or sounding tubes. Full tanks should be
completely full into the vent or fill lines above the tank. Empty tanks should
be sucked down until the stripping pump loses suction. For Load Line stability
tests, empty tanks must have their manholes removed, and if the bottom corner
is not visible from the manhole they must be gas free - safe for men.
6. Freeboards - At
pre-determined positions along the length of the vessel on both sides, a
sounding tape is dropped over the side and the freeboard (distance from the
deck to the water) is measured. By using the lines plan in conjunction with
these freeboards and the specific gravity of the water (see item 7 below) an
accurate representation of the waterline and displacement (vessel's total
weight) will be developed.
7. Specific Gravity - The
density of the water the vessel is floating in varies depending on its salinity
and temperature. A hydrometer is used to determine its specific gravity.
8. Block Movement/Pendulum
9. Calculations - The final
step is to perform approximately five minutes of calculations to determine the
validity of the results. This is done only to determine if the test was
successful, not to give any stability results. If the data is bad, steps 5
through 9 will be repeated. Typical sources for bad data are excessive tank
free surface, high waves & wind, tight mooring lines, grounding, and open
tank cross connects.
C. Stability Analysis
Once the stability test has
been completed, a detailed set of calculations will be performed in the Naval
Architect's office. These calculations will determine "Lightship",
which is the total weight of the vessel (without liquids in tanks or
deadweight), and its center of gravity. With this information any vessel
condition may be analyzed on a computer to determine operational limits.
These general
recommendations are applicable to most vessels.
A. Free Surface
Free surface is the
sloshing of liquid in a tank from side to side. As a vessel heels to one side,
the center of gravity of the liquid in a slack tank shifts in the direction of
the heel, making the heel worse. Narrow tanks have very little free surface, and
are not generally a cause for concern. Wide tanks (larger than 1/3 of the beam)
with free surface can cause severe stability problems. Only one pair of fuel
storage tanks and one pair of fresh water tanks should be slack at any time.
B. Ballast Tanks
The operator should always
know the levels of the ballast tanks. If water inadvertently enters an empty
ballast tank or seeps out of a full ballast tank free surface will result.
Ballast tanks should be kept either completely full or completely empty, and be
checked on a regular basis.
C. Sea Water Holds
Due to the potentially high
free surface of sea water holds, they should be operated only in a completely
empty or completely full condition, and checked periodically to ensure that the
level does not change causing free surface to develop. Sea water holds should
be filled and emptied with the greatest care, by seeking shelter, or by
assuming a favorable heading into wind and sea. No more than one centerline or
pair of P/S holds shall be filled or emptied at a time. When
operating with slush or crushed ice in a hold tank, excess water should be
continually pumped out to minimize free surface effects. Many insurers
now require a level alarm to be installed at the top of each flooded sea water
hold so that the crew is alerted if the water level falls below that point.
D. Freezer Holds
Holds that store frozen
cargo need to be loaded with care, and secured as necessary. In heavy seas,
loose cargo may shift and result in a dangerous list situation.
E. Listing
Never correct a list until
you know the cause. If cargo has shifted resulting in a list, pumping from
tanks on one side to the other can result in a dangerous situation by
dramatically increasing tank free surface.
F. Icing
Stability reports generally
give restrictions for operating under icing conditions. For the
G. Cranes
The use of on-board cranes
at sea can cause a dangerous situation if the resulting list is too great,
leading to a reduction of reserve buoyancy. A stability report usually
incorporates recommendations on usage of cranes at sea. A good rule of thumb is
never to submerge more than half of the available freeboard in the act of
lifting.
H. Freeing Ports
Freeing ports and scuppers
should be kept clear of debris at all times to maintain their effectiveness.
I. Factory Operations
(ref: 46 CFR 28.255)
A space supplied with water
for the sorting or processing of fish must be fitted with a dewatering system
capable of dewatering the space under normal conditions of list and trim at the
same rate as water is introduced. Pumps used as part of the processing of fish
do not count for meeting this requirement. The dewatering system must be
interlocked with the pumps supplying water to the space so that in the event of
failure of the dewatering system the water supply is shut off.
J. Trash Chutes
A trash chute from a
watertight processing space should have a non-return flapper and a means of
securing it closed watertight from outside the space. The area in way of the
chute should be kept clear of machinery and stores for access in an emergency.
The flapper should never be secured in an open position. The chute's operation
should be checked periodically.
K. Weather Tightness
All weather deck doors, air
ports, and vents should be kept closed and securely dogged when operating in
heavy weather conditions. All watertight doors should be kept closed except
when used for passage under safe conditions.
L. Bilges
Bilges should be kept
pumped to a minimum level at all times. Bilge system requirements for all
fishing vessels are described in 46 CFR 28.250 & 28.255.
M. Modifications
No permanent ballast or
other such weights should be added, removed, altered, and/or relocated, and no
watertight bulkheads should be removed or altered unless the effect on
stability has been investigated by your Naval Architect.
N. Anti-Roll tanks
Vessels with exceptional
stability may be equipped with an anti-roll tank. These tanks are designed such
that the liquid sloshes from side to side out of sync with
the vessel's rolling. In a correctly designed tank, the liquid will
slosh to the high side of the tank to reduce the vessel's roll amplitude, and
give a much more comfortable ride. In a poorly designed tank the liquid will
shift to the low side of the tank, increasing the rolling amplitude. Anti-roll
tanks must be "tuned" to each vessel. Since a vessel will behave
differently in a light condition than a heavy condition, an anti-roll tank may
be ineffective or dangerous in an out-of-tune condition. For this reason, an
anti-roll tank should never be put into operation without first calculating its
potentially negative effect on stability.
O. Stability in a Seaway
Care should be exercised
when steering with a following sea. Going too fast may drive the vessel through
the swell ahead onto the downside where the following swell can catch the stern
and throw the vessel broadside to the swells. This "broaching to" may
cause the vessel to capsize. An equally dangerous situation may result if the
vessel's speed is close to the speed of the swell upon which it is riding
causing a loss of steering control.
P. Freeboard
Freeboard is the vertical
distance measured from the water to the deck at side. In some instances your
Naval Architect may recommend a minimum overall freeboard corresponding to the
deepest possible draft.
Q. Deck Loads
Each stability report will
provide guidance for the maximum load (crab pots, cod ends, etc.) which may be
safely placed on deck. All deck loads must be secured in a fashion that will
prevent shifting in a seaway. You may also be limited by the strength of the
deck supporting the load. If you are concerned about deck strength you should
request that your Naval Architect perform a structural analysis.
V. Effect of
Vessel Configuration on Stability
Each vessel has its own
stability characteristics and will tend to be restricted by perhaps two or
three of the criteria limits described in section IIB. Because a similar size
boat was able to place a larger winch on his deck does not mean that your boat
can. It is very important to discuss any proposed changes with your Naval
Architect beforehand to ensure that the stability will not be impaired.
A. Adding Weight
Adding weight high will
raise the center of gravity and reduce stability. Adding weight low will lower
the center of gravity and increase initial (upright) stability, but this is not
always beneficial. Adding weight on vessels with low freeboard causes the deck
edge to submerge at a smaller heel angle, and the righting arm curve to drop
off sooner.
B. Removing Weight
Removing weight below the
main deck will reduce the initial stability, but may increase the range of
stability (the angle where the righting arm drops to zero). Removing weight
above the main deck will increase both the initial stability and the range of
stability.
C. Weight Growth
All vessels will get
heavier and experience a rise in the center of gravity as time passes. This is
because equipment, spares, dirt, paint, etc. tend to accumulate. You should
make an effort to keep your vessel in a clean condition to reduce this
potential problem. We recommend a new stability test and report be prepared
every five years, and whenever you add/remove/relocate major pieces of
equipment. It is also advisable to perform an annual vessel cleanout, removing
nonessential equipment & gear.
D.
There are various methods
of altering an existing hull that can significantly alter load carrying and
stability characteristics, including sponsoning, midbody extension, deepening, raised poop decks, stern
extensions, and house additions. As a general statement, any hull alteration
which creates additional freeboard has the potential for improving stability
and/or increasing vessel payload. Each of the listed techniques can have
different benefits and costs for a particular vessel design.
Any hull alteration is
expensive. To obtain the best benefit to cost factor, advance consultation with
your Naval Architect concerning your project objectives can pay high dividends.
The same computer models used for stability calculations can be utilized to
forecast stability and loading performance of different configurations. A few
words relative to each modification technique follow:
1. Sponsoning
- Sponsons are extensions to the beam of a vessel,
usually resulting in a second set of wing tanks. A carefully designed set of sponsons will be almost unnoticeable to the eye, and will
dramatically improve stability and cargo carrying capacity. Wider vessels tend
to have a faster roll period (time to complete one roll cycle), which may not
be desirable in extreme cases.
2. Midbody
Extension - For vessels with good stability, a midbody
lengthening is a good way to increase the cargo carrying capacity. Vessels with
poor stability may not benefit from a midbody
lengthening because the stability is changed very little, and the extra cargo
space may not be usable.
3. Deepening - Adding
watertight space on top of existing working decks increases freeboard, thereby
improving stability. This can be very effective when a wet hold vessel is over
tanked (too much weight and too little buoyancy), or more combined deck and
hold cargo is desired.
4.Raised Poop Decks - A raised poop is a
modified form of deepening. The additional buoyancy aft does not increase
freeboard, but does increase righting arms as a vessel rolls. This relatively
minor modification can significantly improve stability characteristics.
5. Stern Extension - A
stern extension typically has very little effect on the overall stability. Its
common uses are to get the stern further out of the water if the aft deck is
very wet, and to increase working space on the aft deck.
6. Adding
a house - The addition of a full width house will make a vessel heavier and
reduce upright stability, but will increase righting arms as the vessel rolls.
If your boat has sufficient upright stability but has difficulty meeting the
stability range requirements, the addition of a watertight house may be helpful
to the stability.
VI. Fishing
Vessel Regulations
On
There are two very
important definitions: "Substantial Alteration" and "Major
Conversion". There is no clear boundary between these definitions. A
vessel undergoing a "Major Conversion" must meet several additional
stability criteria, which may further limit operations.
New vessels built on or
after September 15, 1991 must meet unintentional flooding (damaged stability)
per 46 CFR 28.580, which may be extremely difficult or impossible to meet for
vessels with large open holds or engine rooms. This requires vessels to survive
flooding with stability margin when damaged lengthwise 10% of the vessels
length (or 10 feet if less), and transversely 30" from the side shell. All
spaces with through-hull fittings, such as engine rooms and lazarettes,
must also be assumed simultaneously flooded. The alternative to meeting this criteria is obtaining and maintaining a Load Line.
An evaluation of the
regulatory impact will be essential for all future changes to hull form or
carrying capacity. Two essential stages of project planning will be:
1.Clear determination of applicable regulatory
requirements.
2.Preliminary engineering verification that the
modified vessel will satisfy the regulations.
In unique circumstances for
which no precedent has yet been established, the correctness of a preliminary
evaluation of applicable requirements should be offered to the local U.S. Coast
Guard OCMI for confirmation. Qualified Naval Architects can then verify that a
planned alteration will satisfy both the vessel Owner's objectives and
regulatory requirements.
VII. License
Limitation Program (formerly Fishing Vessel Moratorium)
The former Fishing Vessel
Moratorium has been superseded by the License Limitation Program. The full text
of the regulations may be found 50 CFR 679.4, which is also available on the
following web site: http://www.fakr.noaa.gov/regs. This program limits certain
catcher and catcher-processor vessels in Alaska groundfish
and Bering Sea/Aleutian Island crab fisheries to a maximum length overall
(MLOA) shown on the groundfish license.
VIII. Vessels
Requiring a Load Line or Classification
The following information
is offered only as basic guidance. For the complete text of the law, please
refer to 46 USC Chapter 51, and 46 CFR 42.03. The following definitions apply:
Fishing Vessel (as defined in 46 CFR 28.50):
"a vessel that commercially engages in the catching, taking, or harvesting
of fish or an activity that can reasonably be expected to result in the
catching, taking, or harvesting of fish."
Fish Processing Vessel (as defined in 46 CFR 28.50):
"a vessel that commercially prepares fish or fish products other than by
gutting, decapitating, gilling, skinning, chucking,
icing, freezing, or brine chilling."
Fish Tender Vessel (as defined in 46 CFR 28.50):
"a vessel that commercially supplies, stores, refrigerates, or transports
fish, fish products, or materials directly related to fishing or the
preparation of fish to or from a fishing, fish processing or fish tender vessel
or a fish processing facility."
Existing Vessel (as defined in 46 USC 5101):
"a vessel on a domestic voyage, the keel of which was laid, or that was at
a similar stage of construction, before January 1, 1986; and a vessel on a
foreign voyage, the keel of which was laid, or that was at a similar stage of
construction, before July 21, 1968."
46 USC 5102, Application
(of Load Line Statues) 1995
(a) Except as provided in
subsection (b) of this section, this chapter (LOAD LINES) applies to the
following:
1.
a vessel of the
2. a vessel on the navigable water of the
3. a vessel owned by a citizen of the United States or a corporation
established under the laws of the United States or a State, and not registered
in a foreign country.
4. a public vessel of the
5. a vessel otherwise subject to the jurisdiction of
the
(b) This chapter (LOAD
LINES) does not apply to the following:
1.
a vessel of war
2. a recreational vessel when operated only for
pleasure
3. a fishing vessel
4. a fish processing vessel of not more than (less
than) 5,000 gross tons that:
- was constructed as a fish
processing vessel before
OR
- was converted for use as a fish
processing vessel before
5.
a fish tender vessel of not more than 500 gross tons
that:
- was constructed, under
construction, or under contract to be constructed as a fish tender vessel
before
AND
- is not on a foreign voyage or
engaged in the Aleutian trade (except a vessel in that trade assigned a
load line at any time before
6.
a vessel of the
7. a vessel of less than 24 meters (79 feet) overall
in length.
8. a public vessel of the
9. a vessel excluded from the application of this
chapter by an international agreement to which the United States Government is
a party.
10. an existing vessel of not more than 150 gross tons
that is on a domestic voyage
11. a small passenger vessel on a domestic voyage
12. a vessel of the working fleet of the Panama Canal
Commission not on a foreign voyage.
46 CFR 28.720 Survey and Classification (of Fish Processing Vessels)
Each Fish Processing Vessel
which is built after, or which undergoes a major conversion completed after
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