WATER POLLUTION CONTROL RESEARCH SERIES • 15020DGR 8/70
FLEXIBLE HOLDING TANK FOR
PLEASURECRAFT SANITARY SYSTEMS
ENVIRONMENTAL, PROTECTION AGENCY • WATER QUALITY OFFICE
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe the
results and progress in the control and abatement of
pollution in our Nation's waters. They provide a central
source of information on the research, development, and
demonstration activities in the ¥ater Quality Office of
the Environmental Protection Agency, through inhouse re-
search and grants and contracts •with Federal, State and
local agencies, research institutions, and industrial
organizations.
A triplicate abstract card sheet is included in the
report to facilitate information retrieval. Space is
provided on the card for the user's accession number
and for additional uniterms.
Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Head, Project Reports
System, Planning and Resources Office, Office of Research
and Development, Water Quality Office, Environmental Pro-
tection Agency, Room 1108, Washington, D. C. 202^2.
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FLEXIBLE HOLDING TANK FOR PLEASUEECRAFT SANITARY SYSTEM
By
UNIROYAL, INC.
Research Center
1361 Alps Road
Wayne, N. J. 074-70
for the
WATER QUALITY OFFICE
ENVIRONMENTAL PROTECTION AGENCY
Project No. 15020 DGR
August, 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 - Price 55 cents
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication.
Approval does not signify that the contents necessarily
reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommenda-
tion for use.
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ABSTRACT
The purpose of this effort was to develop a flexible holding tank to
collect waste products in small pleasurecraft. Its use is primarily
proposed as a convenient means for modifying existing craft so as to
comply with proposed standards for the discharge of sewage from
vessels.
A survey delineated numerous locations where a flexible tank could be
located in the various craft under consideration and a corrugated
design was conceived which will conform to most of these.
The placement of the flexible tank in several locations was success-
fully demonstrated using a boat mock-up. Performance tests, also
conducted, showed that the tank could be used both as a simple
holding tank or as a reservoir in a recirculating sanitary system.
Potential construction materials were tested by immersion in a variety
of solutions with which a container might come into contact. The list
included fuel and lubricating type hydrocarbons and aqueous solutions
of several sanitary-system cleaners and treatment chemicals. Nylon
fabric coated with NBR, Neoprene or polyurethane proved to be satis-
factory for the application.
Rocking tests proved that wear is not a serious factor as regards the
application of a flexible holding tank on small pleasurecraft.
Installation of the flexible holding tank is relatively simple. An
overall installation cost was not projected, however, because the
cost of the container itself will vary considerably with the number
produced and an economic study was not undertaken as a part of this
effort.
This report was submitted in fulfillment of Contract #14-12-506 under
the sponsorship of the Federal Water Quality Administration.
iii
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CONTENTS
Section
I Conclusions and Recommendations 1
II Introduction 2
III Objectives 3
IV Application Analysis 4
V Design Analysis 8
Sizing Considerations 8
Construction Materials 12
Systems Layout 12
Transfer Line Details 16
VI Testing Program 23
Application Tests 23
Immersion Tests 28
Use Tests 32
Rocking Tests 34
VII Glossary 36
VIII Appendix 37
IV
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FIGURES
PAGE
1 Typical Space Configurations and Accordion
Design Holding Tank 10
2 Accordion Design Flexible Holding Tank
Configuration 11
3 Typical Pleasurecraft Sanitary Hook-up 13
4 Sanitary System with Holding Tank 14
5 Recirculating Type Sanitary System 15
6 Tank Discharge Port Fitting 17
7 Bulkhead Clean Out Fitting and Purging Pump
Hose End Fitting 18
8 Vent Line Details 20
9 Vent Line Assembly into Tank 21
10 Mock-up Boat Section 24
11 Installed Tank on Mock-up Boat Section 27
12 Deep Keel Section on Rocking Test Platform 35
v
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TABLES
Page
I Tensile Strength and (Elongation) of
Candidate Impregnated Fabrics 30
II Tensile Strength and (Elongation) of
Candidate Liner Elastomers 31
III Sanitary System Use Test Summary 33
VI
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SECTION I
CONCLUSIONS AND RECOMMENDATIONS
It has been shown that a flexible container made of elastomer-coated
nylon fabric provides an acceptable and versatile holding tank for
upgrading a sanitary system on small pleasurecraft. It is particularly
suited to craft in the 22 to 28 ft length classification where open
space is not generally available for the installation of a rigid tank.
An accordion tank design with a 14 in. x 24 in. cross section can be
installed in a majority of the hidden spaces found on small pleasure-
craft. It can be folded and inserted through a relatively small access
opening and used as a simple holding tank or as a reservoir in a
recirculating sanitary system. Clean out is readily accomplished with
a diaphragm type sludge pump which would be located at dock side
servicing stations.
Used as a simple holding tank, a 20 gal. unit will provide approxi-
mately 40 flushes and thereby be suitable for a party of four for a
weekend or two-day cruise. The same size tank used as a reservoir in
a recirculating system will provide about 140 flushes.
Prototype flexible holding tanks should be fabricated and installed on
a variety of craft where their operation can be monitored and their
practical usefulness demonstrated to the general public and potential
manufacturers.
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SECTION II
INTRODUCTION
Until recently, the type and operation of pleasurecraft sanitary
systems have not been seriously regulated. Consequently the vast
majority now in operation discharge waste products directly into the
surrounding water. This is generating a sizable pollution problem in
many of our lakes and harbors - especially around marinas where boats
are generally concentrated. The Department of the Interior, working
with industry and Coast Guard figures, have estimated that there now
exist a total of 8,000,000 recreational watercraft in the United States
(1967) and that over 1.3 million are equipped with toilet facilities,
most of which contribute to this problem.
Several methods are available for handling sanitary waste on small
pleasurecraft other than dumping it over the side. The most direct
involves collecting it in a holding tank for later transfer into a
shore facility. Manufacturers who supply integrated toilet and hold-
ing tank units to the house trailer and aircraft industries are now
offering them for use on boats. Macerator/chlorinators are available
which incompletely treat the sewage before it is discharged into the
sea. One manufacturer offers a unit in which the sewage can be incin-
erated. For large boats involving a sizeable crew, complete treatment
systems should be considered and used.
Two service organizations exist whose interests include sanitary
systems on small boats. One of these, the Yacht Safety Bureau, Inc.,
is sponsored by a marine manufacturing association and several insurance
companies. It is set up to test and certify products for the boating
industry. This organization is mainly interested in the safety aspects
of a product to the user, however, and does not specifically concern
itself with the resulting problem of pollution. The second organiza-
tion, the National Sanitation Foundation, on the other hand is actively
concerned with pollution and has undertaken to formulate specifications
for watercraft sewage disposal systems with this basic viewpoint in
mind.
The main impetus to adopting improved means for handling sewage on
boats is the adoption of appropriate codes by state and federal
legislative bodies. Unfortunately (at least for the present) the laws
are quite inconsistent, one from the other, but a preference does seem
to be developing for the holding tank technique for controlling the
pollution problem. Officials favor tamper-proof permanent hook-ups
that lend themselves to pumping out at dock side only. Both the City
of Chicago and the State of New York now require the use of holding
tanks of this type. Federal standards will not specify any type of
equipment but will merely set effluent requirements.
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SECTION III
OBJECTIVES
It was our objective under the subject contract to demonstrate the
capabilities of a flexible holding tank for upgrading the sanitary
systems of existing pleasurecraft to the point where they conform to
new antipollution codes. These codes require that sewage generated
on a boat be collected and stored for later delivery to a shore treat-
ment facility. A flexible (collapsible) tank lends itself to being
installed in hidden and out-of-the-way spaces on existing boats with a
minimum amount of structural dislocation.
To demonstrate that a flexible container would adequately serve as
described, a program involving three phases was undertaken:
Phase I - An Application Analysis
Phase II - A Design and Fabrication Effort, and
Phase III - A Testing Program
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SECTION IV
APPLICATION ANALYSIS
The application analysis was directed at answering the following
questions:
1. What are the merits of the various means for controlling
the pollution problem caused by small pleasurecraft?
2. How should a holding tank be integrated into a pleasure-
craft sanitary system?
3. Does a flexible holding tank offer unique possibilities
for upgrading an existing pleasurecraft sanitary system?
4. What is the optimum size (and shape) for a flexible
holding tank to be used on small pleasurecraft?
Information of a general interest concerning the above was obtained
from the following sources:
1. State and federal laws.
2. Manufacturer's literature.
3. Specifications promulgated by the Yacht Safety Bureau
and National Sanitation Foundation.
4. Interviews.
5. Field trips.
Regulations vary widely from state to state on the subject of control-
ling the discharge of waste from watercraft. Some states still have
no regulations. A majority of the states that have regulations express
a preference for a holding tank, but many also permit the use of a
macerator/chlorinator.
Toilets on existing pleasurecraft are generally designed to discharge
sanitary waste products directly into the surrounding water. Hand
pumps are used on cheaper models and electric pumps on the more
elaborate but the effect on pollution is the same. The practice is
particularly objectionable in harbors and marinas where the relatively
high concentration of boats in a limited space results in a serious
pollution problem.
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The raacerator/chlorinator is a type of holding tank wherein sanitary
wastes are broken up and treated with chlorine for a short interval
prior to dumping overboard. When operated properly these are effective
for killing bacteria, and several states have approved their use on
pleasurecraft. Many health officials are reluctant, however, to approve
a device which is so completely subject to operator control and which
does not, in any event, prevent solid nutrients from being discharged
into the water.
Toilets designed to incinerate waste are not popular for small pleasure-
craft because of the reluctance of owners to carry, let alone, burn,
highly inflammable products on their boats. Self-contained treatment
plants are generally too bulky to install on small boats.
Owners confronted with laws that require holding tanks have generally
followed two courses of action. Some have installed rigid tanks and
integrated them into their existing sanitary system. Others have
replaced their toilets with small self-contained units in which toilet
and tank are integrated into one compact assembly of the type that was
developed for the aircraft and house trailer industries.
Holding tanks can be used strictly as a collection basin or as a
reservoir in a recirculating system. Advocates of the former stress
the value of a clean water flush while advocates of the latter point to
the greater number of flushes that are possible. In the recirculating
set up, the reservoir is initially half-filled with water. To this is
added a highly perfumed chemical which acts to break down solids. The
water is used over and over again for flushing until the added waste
products fill the tank.
Flexible containers have not been offered to the trade for use as
holding tanks. To determine if this is a feasible proposition and if
it would offer any unique advantages over the rigid tank installation,
a survey was conducted to ascertain the space available for holding
tanks on existing pleasurecraft ranging in length from 20 to 50 feet.
This information was obtained by studying plans in books and magazines,
and viewing boats in a variety of locations. Facilities visited
included:
1. New York Boat Show, New York, N. Y.
2. Yacht Haven Showroom, Stamford, Conn.
3. Doan Harbor Marina, Stamford, Conn.
4. Norwalk Cove Marina, East Norwalk, Conn.
5. Hammel's Marine Center, Freeport, L. I., N, Y.
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6. Viking Boat Co., New Gretna, N. J.
7. Barnagat Marine Mart, Barnagat, N. J.
8. Sanborn's Marina, Waretown, N. J.
9. Chicago Municipal Dock, Chicago, 111.
Where possible, photographs were taken of areas on the many boats
viewed which would accommodate a holding tank. Also, physical measure-
ments were made and sketches were produced for later analysis and
review.
Four basic classes of boats were investigated. The most prominent was
the powered yacht, usually with inboard engine, or lately with inboard-
outdrive power. All are over the 20 foot length classification and are
generally equipped with some type of toilet. Outboard powered run-
abouts, event those over 20 feet in length, were not included in the
survey because they normally have no toilet facility.
The second class comprised the auxiliary powered sailboats. These vary
in length from slightly under 20 feet to over 50 feet for the more
elaborate models. The smallest models generally do not have toilets.
Sailboats without power range from belov/ 12 feet to above 50 feet,
again the smaller models do not have toilets.
The final classification considered was the houseboat. The popularity
of this craft has developed only in recent years. Prior to 1965 there
were probably less than 3,000 boats of this type in actual use. In
that year, however, 1,250 additional units were built. This was
increased to 3,000 in 1968 and several builders planned to double their
output in '69 and '70. Houseboats are planned for complete liveability
and practically all are provided with galleys as well as toilets.
Flexible tanks appear to best meet the requirements of boats between
22 and 28 feet. Above 28 feet, space is occasionally available for
installing a rigid tank and above 35 feet this is almost always true.
Below the 22 foot length classification, boats are rarely equipped
with or need toilets.
Ideally, space for a holding tank is an area or cubby hole which the
owner does not consider he needs for another purpose. Except on the
larger boats, therefore, it generally consists of hidden space under
decking and/or behind bulkheads. We found it to comprise a variety
of configurations and quite often to be limited in size. To apply a
rigid tank in these situations would require that it be custom built
for each application. To install it would require the removal of at
least one complete wall of the selected confined cavity.
Normally a flexible tank would be oversize of the anticipated installa-
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tion space. This type of tank could be folded to insert through a
relatively small access opening and would expand, when used, to the
maximum confines of the space in which it is located. One design
should serve a variety of space configuration needs as should become
amply clear in the remainder of this report.
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SECTION V
DESIGN ANALYSIS
Criteria for the design of a prototype holding tank are summarized
below:
1. Moderately low first cost
2. Simple to operate
3. Negligible maintenance
4. Tamperproof
5. Compatible with dockside pump out and storage facilities
6. Odor free
7. Light weight and easily handled and installed
8. Applicable to large numbers of watercraft
9. Resistant to salt water and other corrosion and fatigue effects.
To meet these criteria the entire system is involved and is so dis-
cussed below:
Sizing Considerations
A holding tank should be as large as possible to reduce the incon-
venience and expense of purging it and, of course, must be large enough
to satisfy the owner's needs. On the other hand, space is likely to be
a limiting factor and the effect of a relatively large tank on boat
trim must be taken into account. These are matters for the boat owner
to consider when he plans his installation.
For our purpose it was assumed that the owner will want a holding tank
that tends to match his particular boat design. One that is planned
to accommodate four people for a week-end cruise, therefore, should
have a holding tank suitable for eight man-days use. Based on adver-
tizers literature (and later verified by our own tests), sanitary
waste (including flushing water) accumulates at a rate of approximately
2-1/2 gallons per day per individual. Applied to several arbitrary
boat classifications, this works out as follows:
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Boat
Length
Class
22 - 28
28 - 35
Occupancy
2 to 4
4 to 6
Suggested
Waste Tank
Capacity3
(gal)
10 - 20
20 - 35
No. of
Flushes
Provided
20 - 40
40 - 70
35 - 50
a
6 to 8 -I- 35 - 50 + 70 - 100 +
Suitable as simple holding tank for two-day cruise
Since the flexible tank will show up to greatest advantage in a small
boat with limited space, it follows that a 20 gallon size is probably
optimum for this particular product. Unrestricted, it should be large
enough for most boats in the 22 to 28 foot classification and for many
in the 28 to 35 foot group. Actually, however, the number of flushes
provided may be limited by the space selected for its installation.
If space is excessively limiting, a recirculating system which will
facilitate 3-1/2 times as many flushes might have to be considered.
This type of hook-up could, in fact, make the 20 gallon tank suitable
for even the largest size pleasurecraft.
A flexible tank larger than 20 gallons would require such elaborate
supporting means that its advantage over a rigid tank would be
negligible.
Based on the survey conducted under Phase I of this program, it was
noted that the space which is available for the installation of a
holding tank is generally rectangular, both in plan view and in
elevation when viewed along the length of the boat. The shape
coincident with the boat's cross-section, however, is usually similar
to one of the several shown in Fig. 1. It became gradually apparent
that an accordion-pleated tank would conform to all of these config-
urations (see lightface lines in Fig. 1) and furthermore that a
14 x 24 in. cross section was the proper size for most applications.
Such a tank is shown schematically in Fig. 2.
From a fabrication point of view, it was agreed to provide ten 60°
V-shaped pleats to form the accordion. Normally this tank will hold
18 gallons of fluid but will collapse to fit a much more restrictive
space and can actually expand to 21 in. to provide a capacity of
nearly 25 gallons.
To facilitate hooking the tank into the sanitary system, two access
ports are required. These were placed side by side along the shortest
edge of one of the flat end surfaces of the tank. Each comprises a
flanged hollow rubber sleeve which is integrally cured into the tank
and into which fittings can be inserted and clamped. The tank inlet
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Figure 1. Typical Space Configurations and
Accordion Design Holding Tank
10
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1-1/2" I.D.
Inlet Port
Figure 2. Accordion Design Flexible Holding Tank Configuration
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port I.D. is 1-1/2 in. to match the usual toilet discharge line. The
exit port is made with a 2 in. I.D. to permit insertion of the special
fitting and dip pipe assembly. The vent opening is located and cut
after the orientation of the installed tank is established.
Construction Materials
To achieve real flexibility combined with ruggedness and reasonable
weight required that the tank be made of an elastomer-coated fabric.
The specific construction selected, based on considerable experience
in the manufacture of flexible tanks, is as follows:
Elastomer type: nitrile rubber, Uniroyal Compound No. 3010
Fabric reinforcement: Fiberthin nylon, 2 oz/sq yd
Wall construction: 0.042 in. total thickness, 30 oz/sq yd
total weight
Elements of tank wall:
(a) single-ply impregnated fabric, 0.012 in. thick,
7 oz/sq yd, Uniroyal Style No. 5200 (rubber and
fabric as described above)
(b) nonreinforced rubber liner, 0.030 in. thick,
Compound No. 3010 as above.
The prototype tank made for the test program was assembled by a hand
layup technique which is familiar to fabricators throughout the
industry. Sheeting was cut to size, taped and pan cured into the
finished item. The corrugations were formed from a series of frames
taped to one another at their inner and outer edges. Tooling and
more modern production techniques would be required for the fabrica-
tion of a commercial product. Tests described later in this report
have shown that both the nitrile rubber used to impregnate the
reinforcing fabric and the nonreinforced tank liner could be replaced
by either Neoprene or a polyurethane rubber at the manufacturer's
discretion.
Systems Layout
The majority of small pleasurecraft sanitary facilities are comprised
simply of a water closet (toilet) and a dual action pump connected
directly into the surrounding water. This hookup is shown in Fig. 3.
The system can be altered to include a holding tank as shown in Fig. 4,
or can be converted into a recirculating system, wherein the tank
becomes a reservoir as shown in Fig. 5.
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Hand
Flush
Pump
Closet
Figure 3. Typical Pleasurecraft Sanitary Hook-
Up
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Clean-out
Fitting (4
Closet
Discharge
ine
6
Holding
Tank
Clean-out Line
©
Dip Pipe
©
Figure 4. Sanitary System with Holding Tank
14
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Closet Discharge
Line
Hull
Reservoir
Recirculating and
Clean-out Line Cb\
Figure 5. Recirculating Type Sanitary System
15
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For the holding tank hookup, the pump discharge line is connected into
the holding tank filling port. A cleanout line is attached to the exit
port and terminates at a cleanout fitting. The vent line is attached
to the top surface of the tank and terminates in a housing which can
be filled with activated carbon to trap odors that emanate from the
tank. It is generally convenient to handle the carbon in a small
cloth bag and simply insert it unopened into the vent filter housing.
The hookup is similar for the recirculating system, except that the
water supply line is cross-connected into the tank cleanout line. A
sealed closure on the cleanout fitting makes it possible to circulate
the fluid from the tank through the closet with the closet pump. To
put into operation, the tank must be filled with water to roughly half
its designed capacity. This water is treated with a chemical designed
to break down the solids and control the odor problem. When operated,
the tank fills at a much slower rate than it does when used as a
simple holding tank hookup because additional flushing water is not
being added to the system on each use.
A dip pipe installed in the bag prevents the latter from sealing off
the discharge port prematurely during the purging or cleanout operation,
Regulating ordinances are not in general concerned with waste from
galleys, and basically, the galley on a small runabout is not an
important contributor to the pollution problem. Cooking is discouraged
by the fact that water needed to pursue this activity has to be
carried aboard the craft. Also, garbage from a picnic-style meal is
usually easily bagged and carried off the boat. If the owner desires,
however, a galley sink suitably equipped with a masticator, positive
discharge, and check valve can be connected into a holding tank in
common with a toilet.
Transfer Line Details
The major elements of the fluid transfer lines as shown in Figures 4
and 5 are numbered (T) through(?) respectively. Elements of the tank
vent line are numbered(8)through @. While a choice of materials does
exist here, a convenient combination which was used for our own testing
program is summarized below:
(T) 1-1/2 in. insert type PVC elbow
(2) pair of 1-1/2 in. insert type PVC elbows modified as
shown in Fig. 6
(3) 1-1/2 in. insert type PVC tee
(4) 1-1/2 in. pump out bulkhead fitting (modified fuel
bulkhead fitting as shown in Fig. 7)
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Discharge
Line Position
2-3/4" max.
Modified 1-1/2" PVC
Insert Type Elbow
2" O.D. Coupler
(Rotate elbows as desired
for installation prior to
cementing into coupler).
Dip Pipe
Position
Figure 6. Tank Discharge Port Fitting
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1-1/2"
aske t
/
/
/
/
1
2"
1
1
A
-*: — ;_ Purging Pump
\
\
3° Total Taper
Sealed Closure
<
Decking
Ream to accept
Purging Pump riose
End Fitting
Bulkuead
Clean Out
Fitting
Figure 7. Bulkhead Clean Out Fitting and
Purging Pump Hose End Fitting
18
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Q5) existing lines as recommended by closet supplier
\6) 1-1/2 in. flexible reinforced vinyl hose
(7) 15 in. length - 1-1/2 in. flexible reinforced vinyl
hose perforated x^ith 3 dozen 3/16 in. x 3/4 in. slotted
openings distributed evenly throughout its wall
(8) 5/16 in. Tygon tubing
(9) 1/4 in. Imperial brass ball check valve with spring
removed
@) 3/8 in. bulkhead fitting shown in Fig. 8
(ll) Perforated charcoal container (filter housing) shown
in Fig. 8
Q2) Penetration fitting shown in Fig. 9
The vent is necessary to release gas formed by the decomposition of
sewage in the holding tank, since the pump-out fitting and toilet
flushing pump prevent its escape via the larger lines. To be
effective, the vent penetration fitting should be located at the
highest point in the bag. It is designed to fasten into a bulkhead
or decking so as not to sag, clog, or become submerged in the fluids
in the tank and thus become inoperative. This is shown by Fig. 9.
The check valve in the vent line is required to insure complete dis-
charge of the fluids from the tank during the clean-out operation.
The discharge pump is designed to expel air and develop a suction
sufficient to remove the sewage, and an open vent line could cause
this operation to malfunction. Removal of the spring in the ball
check is necessary to prevent any inadvertent build-up of pressure
from occurring in the holding tank.
Any supplier of flexible holding tanks must arrange to make the
required fittings available to the user - probably in the form of
a kit. Most can be obtained from either an industrial or commercial
supply house, but it might be difficult for the average boat owner to
locate all of them. Also a few must be modified for this particular
application.
The modified bulkhead fitting shown in Fig. 7 is equivalent to the
fitting being used by boat owners on Lake Michigan. All municipal
pump-out stations are equipped with a hose end-piece designed to
match this fitting for executing the pump-out operation.
Flexible reinforced vinyl hose and associated PVC fittings are available
from any plumbing supplier. Holes can readily be cut into a short
19
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Rain Cover
Perforations
2" x 2" x 5"
Housing
5/16" Tygon Tubing
(to odor filter)
./4" Imperial Ball Check
Valve (spring removed)
5/16" Tygon Tubing
(to container)
\
Activated Carbon
Odor Filter
" Nut
Vent Line Bulkhead
Fitting (Bronze)
Tygon Tubing
(to bulkhead
fitting)
Figure 8. Vent Line Details
20
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5/16" I.D.
Tygon Tubing
3/8" Nuts
Flexible Tank
Decking
Penetrating
Fitting
(Bronze)
Figure 9. Vent Line Assembly into Tank
21
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length of hose to form a dip pipe. Joints with fittings are made up
with a standard hose clamp supplemented with plastic tape to insure
an air-tight seal.
22
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SECTION VI
TESTING PROGRAM
During the course of the work the question arose as to whether a
corrugated tank would merit the added expense required for its
fabrication. Both a plain and corrugated tank were therefore
fabricated and included in the tests to be described below. Also
included were tests in which the containers were used as a simple
collection basin and some where they were used as a reservoir in a
recirculating sanitary system. The overall program involved four
types of tests:
1. Application tests
2. Immersion tests
3. Performance tests
4. Rocking tests
Application Tests
The application tests were designed to demonstrate the; advantages of
a flexible holding tank for use in a small pleasure craft. The test
facility consisted of a composite boat section, the elements of a
sanitary system, and a sewage discharge pump.
The simulated boat section is shown in Fig. 10. It provides five
typical locations where a holding tank might be installed in a 22-28
foot pleasure boat. The reader should understand that these spaces
do not necessarily exist in the same cross-section (as they do in the
mock-up) but wherever located they undoubtedly would be accessible to
the boat's toilet. The spaces, which represent typical ones found in
actual boats, include:
1. The wedge-shaped space under the toilet
2. A wedge-shaped space in the deep keel
3. The shape offered by a shallow keel
4. An askew shape in the rope locker, and
5. An open space found in a typical motor chamber
The mock-up boat section (full size) was made of plywood. It was
designed to tilt 15° to the right or left of vertical and thus simulate
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Installation Space Summary
1 Under Head
2 Deep Keel
3 Shallow Keel
4 Rope Locker
5 Open Space
Partial View
Showing Alternate Keel
Purging Pump
(Simulated
location
on Dock)
Head
Compartment
gull View
Figure 10. Mock Up Boat Section
24
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extremes a boat might assume in a rough sea. The center area is
logically a cabin interior, except when used as we did to represent
open space in a motor chamber. The deep and shallow keel spaces
(2 & 3) were designed to replace one another and thus simulate a
sailing boat and motor cruiser, respectively. Space similar to that
represented by 1 and 3 in the mock-up is often found under bunk beds
in a variety of crafts.
The discharge pump was located at a height typical for a dock used for
medium sized pleasurecraft at low tide. The pump selected for the
test was designed to pull a suction head of 20 feet and thus would be
suitable for practically any condition imaginable in a lake or seashore
marina. Sea water was furnished along side the hull in a 55 gallon
drum.
o
The toilet used on the mock-up was a standard hand-pumped marine type
found typically on small pleasurecraft. Many are now equipped with
electric pumps, but the operation is essentially unchanged.
The object of the application test was to determine the ease and/or
problems encountered in installing a flexible holding tank aboard a
small pleasurecraft and to check its operation for any malfunctions,
deficiencies, etc. A qualified mechanic with a normal variety of
handyman tools and the necessary supply of hose and fittings was
assigned the task of installing the tanks into each of the assigned
spaces. The actual installation, aside from the tedious and time-
consuming tasks of rounding up tools and materials, required from two
to three hours at each location. Obviously this could vary consider-
ably depending on such factors as the remoteness of the tank's location
to the boat's toilet. The task consisted of the following:
1. Cutting feed-through holes for hose and vent lines in
bulkheads and decking
2. Providing arm-size access openings through bulkheads
and/or decking - one being large enough (an 8 in.
square) to insert the flexible holding tank.
3. Installing supporting walls to contain the tank on all
sides where unsupported heights were deemed excessive.
Existing bulkheads, decking, ribbing and hull are used
to the fullest extent possible here. A basket, formed
of expanded metal, was fabricated for containing the
tank in the open motor space.
1. Series M8000 diaphragm pump manufactured by Mansfield Sanitary,
Inc. A similar pump, Model 204 EC, is available from ITT,
Marlow Pump Div.
2. Groco Model EB, hand operated
25
-------
4. Connecting the holding tank and discharge line into
the sanitary system.
5. Closing the exposed access opening.
Photographs were taken of each installation as it was pumped full by
the hand-operated toilet pump, tilted at various stages and emptied by
the discharge pump. Pictures accumulated during this procedure are
reproduced in the Appendix. Fig. 11 is an enlargement of a typical
installation.
Generally speaking, no difficulty was encountered with filling and
emptying the tanks in any of the locations designated nor at any
degree of boat tilt. The perforated dip pipe was found to be essential
for insuring complete discharge of the tank. The need to install the
vent line at the highest point in each setup was also demonstrated.
By watching for water rising in this line (which consisted of trans-
parent Tygon tubing), one could tell when the tank was nearly filled.
Due to the inherent flexibility of the holding tank, however, numerous
flushes were always possible even after water was first noticed in the
vent line.
The amount of water contained by the two test tanks when filled at the
various installation locations is summarized in the following table.
Location Filled Capacity (gal.)
Number Corrugated Tank Plain Tank
(7) Under head 8.2 6.8
(|) Deep keel 14.0 13.6
(?) Shallow keel 7.3 7.3
(4) Rope locker 15.7 12.8
(5) Motor chamber - basket 18.0 18.4
Approximately 2 to 4 quarts were left in the system after purging, but
this amount could readily be contained in the noncollapsible hose used
in the respective hook-ups. By visual examination it was noted that
the container itself was literally wrung dry during the clean-out
procedure.
The corrugated tank was far simpler to handle than the plain tank.
Because of the pleated design, it tended to lay flat and expand on
filling as it was expected to do. The corrugations provided a cir-
cumferential rigidity which aided in positioning it through blind
access openings. The plain tank behaved in exactly the opposite
manner. It was very difficult to identify the lower corners of the
26
-------
Fig. 11 - Installed tank on mock-up boat section
27
-------
tank to position it in a blind hole and to tell if the bottom surface
was spread out fully or not. Often a part of the bag was turned under
itself and/or folds existed which never opened up fully on filling.
Nevertheless it must be acknowledged that this problem was of no real
significance - whether folded grotesquely or not, the plain container
usually filled to the same capacity as the corrugated design. Only
when filled to the maximum in an unrestricted situation would the
corrugated tank provide a substantially greater capacity (25 gal.)
Immersion Tests
Several candidate materials of construction for flexible holding tanks
were immersed in a variety of solutions with which the tanks might
come into contact during actual use. The materials and solutions
involved are listed below:
Construction Materials
1. Urethane impregnated 8 oz. nylon fabric, Code 5408*
2. Thermoplastic polyurethane, Code E-9
3. Neoprene impregnated 2 oz. nylon fabric, Code T-71595
4. Neoprene compound, Code 3070
5. Nitrile rubber impregnated 2 oz. nylon fabric, Code 5200
6. Nitrile rubber compound, Code 3010
7. Urethane impregnated 5 oz. nylon fabric, Exptl. 2195
8. Axial cut strip from flexible reinforced PVC hose.
"Code numbers assigned by Uniroyal Plastics and Industrial
Products Co., Mishawaka, Ind
Test Solutions
1. Water
2. Sewage
3. "Vanish" bowl cleaner, 1 cup per 3 gals, of water
4. Thetford Engineering Corp. odor control chemical
"Aqua-Kern1, 4 fluid oz. per 10 gals, of water
5. Monogram Industries 'T-5' treatment chemical for recircu-
lating systems, 5 oz. per 4 gals, of water
28
-------
6. Fed. Spec. XT-S-735 hydrocarbon type III test fluid
(gasoline)
7. Commercial diesel fuel
8. Commercial lubricating oil
Solutions 3, 4, 5 and 6 were renewed every other week. Toluene was
added to solution 6 on the off week to replace the amount that evapo-
rated in a one-week period, it being the most volatile portion of the
simulated gasoline test fluid.
The test solutions were contained in battery jars and maintained at
130°F by submerging in a temperature controlled water bath. Racked
samples were submerged in turn in the test solutions. Degradation is
speeded at elevated temperature, but we were advised not to exceed
130°F because this would kill off micro-organism activity in the raw
sewage.
Samples of the construction materials were immersed in the solutions
listed above and were removed at pre-established intervals and tested
(tensile strength and elongation at break) in order to determine the
extent of any degradation that may have occurred. The tensile
strength of an elastomer without fabric reinforcement is the pull
required to break a sample and is reported in pounds per sq in. of
sample cross-section. The strength of an impregnated fabric is the
pull to break a 1 in. wide sample and is reported in pounds. The
stretch characteristic of the samples is reported as per cent
elongation when stressed to its breaking point. These results are
summarized in Tables I and II. All of the elastomers swelled to
some extent in the hydrocarbon solutions, but the elastomer-coated
nylon samples were relatively stable in this regard. Neoprene
swelled the most, followed by nitrile rubber, polyurethane and finally
PVC.
The nitrile rubber sample (3010) displayed the greatest overall
stability in contact with the varied test solutions. Polyurethane
(E-9) was nearly as good, but the test results on this material were
slightly more erratic. Unsupported Neoprene (3070) was noticeably
degraded in diesel fuel and suffered some loss in physical strength
by exposure to all the other test solutions except gasoline. The PVC
sample cut from a flexible hose was only slightly affected by the
various aqueous solutions but became quite stiff on exposure to the
hydrocarbon fluids.
The several coated nylon samples were affected to a lesser extent by
exposure to the test solutions. "Vanish" bowl cleaner solution appears
to downgrade coated nylon slightly. Also, all of the aqueous solutions
caused the nitrile rubber-coated nylon to blister (noticed on samples
immersed for only one week), but the condition did not worsen with
time. Lining a tank with a thin sheet of elastomer should therefore
be sufficient to protect the nylon thoroughly in the final tank
29
-------
TABLE I
TENSILE STRENGTH* AND (ELONGATION)** OF CANDIDATE IMPREGNATED FABRICS
>iitcrial Aging
Code Period
5200 Unaged
1 Wk.
3 Wks.
8 Wks.
3 Mos.
5408 Unaged
1 Wk.
3 Wks.
8 Wks.
3 Mos.
2195 Unaged
1 Wk.
3 Wks.
8 Wks.
3 Mos.
71595 Unaged
1 Wk.
3 Wks.
8 Wks.
3 Mos.
Water
106
(34)
95
(62)
83
(64)
88
(30)
496
(46)
495
(48)
510
(51)
473
(44)
288
(34)
250
(50)
230
(50)
246
(31)
93
(31)
80
(33)
69
(41)
92
(32)
Aqua
Chcin
114
(38)
86
(54)
61
(47)
86
(25)
490
(49)
500
(46)
515
(53)
518
(48)
270
(34)
255
(50)
253
(55)
222
(30)
77
(33)
94
(35)
86
(36)
100
(33)
T-5 Vanish
93(23) -
109
(36)
95
(53)
86
(51)
89
(30)
-323(44)
460
(46)
510
(48)
500
(48)
518
(49)
- 255(38)
270
(33)
234
(50)
243
(55)
173
(36)
-68(25) •
85
(33)
86
(36)
35
(42)
89
(30)
113
(39)
110
(47)
92
(43)
90
(35)
503
(49)
505
(47)
505
(48)
490
(48)
260
(31)
260
(50)
115
(50)
96
(30)
98
(33)
108
(36)
151
(35)
72
(30)
Gasoline
117
(36)
112
(36)
94
(56)
73
(24)
513
(48)
500
(40)
490
(46)
481
(43)
295
(31)
274
(50)
260
(53)
258
(29)
99
(30)
103v
(33)
87
(39)
84
(34)
Lub
Oil
118
(35)
93
(54)
90
(60)
94
(29)
444
(36)
500
(46)
495
(49)
483
(45)
294
(36)
261
(50)
228
(53)
253
(29)
94
(30)
94
(31)
94
(35)
76
(26)
Diesel
Fuel
116
(36)
85
(48)
92
(51)
88
(25)
500
(49)
538
(46)
521
(46)
505
(45)
294
(33)
264
(48)
220
(48)
239
'(26)
73
(26)
101
(31)
82
(31)
71
(26)
Sewage
^_
105
(34)
89
(54)
101
(63)
92
(26)
475
(48)
465
(45)
510
(52)
520
(49)
279
(34)
289
(41)
248
(46)
258
(31)
76
(33)
81
(35)
85
(39)
80
(31)
* Given in Ibs /in. width of sample
** Given as Z at break of unstressed length
30
-------
TABLE II
TENSILE STRENGTH* AND (ELONGATION)** OF CANDIDATE LINER ELASTOMERS
Material Aging
Code Period
3010 Unaged
1 Wk.
3
8
Wks.
Wks.
3 Mos.
3070 Unaged
1 Wk.
3
8
Wks.
Wks.
3 Mos.
E 9 Unaged
1 Wk.
3
8
Wks.
Wks.
3 Mos.
PVC Unaged
1 Wk.
3
8
3
Wks.
Wks.
Mos.
Water
1,690
(330)
1,700
(305)
1,553
(275)
1,922
(325)
2,385
(630)
1,941
(515)
1,800
(460)
1,467
(410)
4,560
(485)
6,270
(565)
5,725
(550)
4,800
(485)
36
(145)
38
(135)
40
(132)
32
(242)
Aqua
Chem
1,565
(330)
1,765
(315)
1,765
(300)
1,687
(310)
2,400
(610)
2,058
(540)
1,695
(455)
1,320
(390)
4,765
(480)
6; 010
(540)
4,875
(500)
4,180
(432)
39
(165)
38
(158)
37
(177)
31
(230)
T-5
1.790C
1,695
(345)
1,575
(305)
1,590
(300)
1,582
(310)
2,421(6
2,415
(615)
2,090
(530)
1,650
(465)
1,150
(405)
•4,555(4
4,040
(455)
5,175
(500)
4,138
(485)
3,225
(400)
39(181)
38
(188)
33
(157)
33
(118)
33
(246)
Vanish
1,570
(317)
1,675
(305)
1,643
(280)
1,422
(280)
1 1 1 N - . .
>J3)
2,585
(655)
2,155
(545)
2,240
(530)
2,117
(500)
cc\
•D3)
4,505
(462)
3,200
(380)
5,540
(520)
5,045
(495)
40
(170)
37
(167)
38
(155)
38
(268)
Lub
Gasoline Oil
1,735
(365)
2,023
(340)
1,943
(320)
1,845
(315)
2,505
(640)
2,585
(650)
2,235
(640)
2,205
(650)
4,715
(495)
4,315
(435)
2,930
(305)
4,515
(480)
51
(ID
63
(6)
28
(5)
69
(18)
1,995
(365)
2,054
(330)
2,068
(300)
2,092
(325)
2,470
(650)
2,260
(595)
1,985
(590)
1,802
(560)
4,725
(490)
3,930
(330)
4,888
(470)
5,005
(475)
45
(59)
48
(34)
50
(5)
52
(28)
Diesel
Fuel
1,715
(335)
1,830
(330)
1,840
(330)
1,740
(335)
1,028
(460)
760
(450)
640
(475)
235
(395)
3,560
(437)
4,125
(425)
4,810
(560)
2,980
(410)
51
(39)
49
(14)
58
(5)
59
(27)
Sewage
1,735
(337)
1,560
(290)
1,790
(300)
1,800
(315)
1,965
(540)
1,935
(520)
1,840
(470)
1,590
(435)
4,945
(495)
5,750
(535)
6,225
(585)
4,725
(470)
37
(162)
38
(180)
39
(136)
39
(280)
* Given in Ibs/sq in. of original cross section.
** Given as % at break of unstressed length
31
-------
design. Our prototype tanks, for example, have not blistered.
In summary, all of the materials tested except PVC probably could be
used to make a satisfactory flexible holding tank for sewage. The
selection of nitrile rubber coated nylon for fabricating the proto-
type tanks in any event was proven to be acceptable and as good
probably as any other selection that could have been made.
Use Tests
Actual use tests were conducted on the flexible holding tank by con-
structing a room for the purpose in the shop area of the Uniroyal
Research Center. The plain holding tank was used for this purpose
because it incorporated an access opening that permitted examination
of its interior at the conclusion of the testing program. The set-up
also included the Groco toilet used for the application tests previously
described and the required fluid transfer line fittings and hose. The
room was 6x6x8 feet in size and incorporated a small ceiling fan
that was connected in common to the light switch. The tank vent was
terminated outside of the room.
Testing cycles were of relatively short duration because of the large
number of persons who chose to use the facility. A record was
maintained of the type of hookup used, treatment chemicals applied,
and the number of uses involved. This information is summarized in
Table III.
The plain holding tank had a capacity of 18 gals. Used simply as a
holding tank, an average of 38 flushes were accomodated (approximately
1/2 gallon per flush). Used as a reservoir in a recirculating set up,
however, facilitated approximately 133 uses or 3-1/2 times as many.
At no time was it found necessary to use the activated charcoal to
filter odors at the end of the vent line. This line terminated outside
the toilet room in the large shop area and odors were never detected
there. When used simply to collect waste products, the holding tank
was treated with four fluid oz of Thetford Engineering Co.'s Aqua-Kern
deodorizer. In a recirculating system, the tank was precharged with
from 6 to 10 gals, of water and 7-1/2 to 12-1/2 dry oz of Monogram
Industries T-5 sewage treatment chemical. The odor of the T-5 chemical
was dominant at all times but near the end of each recirculating trial,
it had changed sufficiently to become objectionable. The smell seemed
to emanate mainly from the toilet (during flushing), however, rather
than from the vent. For the simulated use tests above, an open mesh
fabric bag was fastened to the toilet discharge line inside the holding
tank. It was placed there to hold the solids and prevent them from
being recirculated until completely dissolved by the T-5 chemical. At
the end of each use cycle, the tank was discharged into the building
sewer. Also, following each sequence the system was cleaned by
filling with fresh water (to which a half can of Vanish bowl cleaner
was added), circulating the solution for several minutes and pumping
32
-------
TABLE III
SANITARY SYSTEM USE TEST SUMMARY
u>
Initial Initial
Water T-5
Uses each day following date activated
Hook up Gallons
recircu- 10
lating
collec-
tion
collec-
tion
recircu- 8
lating
recircu- 6
lating
recircu- 6
lating
Oz.
12%
(4)
(4)
10
7%
7%
local
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Uses Comments
3 18 19 13 14 - - 3 7 9 11 15 - 9 5 136 Odor com-
plaints after
8th day (2)
1 10 18 5 34
9 11 15 8 43
7 15 12 16 - 10 18 20 15 5 - - 10 9 7 137 (3)
10 15 22 - - 5 12 15 11 9 - - 15 114 (3)
10 10 12 10 - - 22 10 20 15 10 - - - 10 6 (3)
(1) Maximum capacity, approximately 18 gals.
(2) Filter bag partially filled with paper after flushing system
(3) Complaints on odor always came near end of run
(4) Four oz of Thetford Engineering Corp. odor control chemical "Aqua Kern" used on these tests
NOTE: Cleaning involved two flushes with fresh water. One cup of Vanish bowl cleaner was
added to 1st flush
-------
out a second time. It was noted at the end of the program that all
organic material had dissolved and had been removed. The fabric
filter, however, was still filled with a paper slurry which had never
dissolved. On the basis of these tests, the use of a filter bag is
not recommended.
The holding tank itself remained in excellent condition throughout
the test.
Photographs of this set-up are included in the Appendix.
Rocking Tests
The rocking test facility consisted of a platform mounted on bearings
which could be oscillated via a motor through a simple rocker arm
linkage. Both the frequency and amplitude of the rocking action were
adjustable. Tests were conducted by fastening a simulated boat section
to the platform, installing a flexible tank in the section and then
rocking the asembly while periodically varying the water level in the
tank. Figure 12 Show the set-up with a deep keel section used to hold
the flexible test container.
As noted during the tests, very little destructive action is generated
with a normal rocking motion. A flexible tank tends to open only to
the extent that is necessary to contain the fluid being held and thus
tends to dampen sloshing which can be serious in a rigid container.
When a partially filled flexible tank is rocked, it tends to fold and
unfold from side to side to accomodate the change in water surface
level. Also, no appreciable rubbing action is produced as the flexible
tank unfolds against the confining walls and then alternately pulls
away.
An attempt was made in one test to aggravate the conditions imposed by
the rocking test facility. Sand was purposely stuck to the painted
surface of the boat section involved and both water and some additional
loose sand was scattered throughout the structure to promote slippage
and wear. This test was stopped after six weeks, however, when
visible signs of wear still failed to materialize.
34
-------
Fig. 12 - Deep keel section on rocking test platform
35
-------
SECTION VII
GLOSSARY
Elastomer - A material which at room temperature stretches under low
stress to at least twice its length and snaps back to the original
length upon release of stress. A rubber.
Fiberthin® - Uniroyal's trade name for a tear-resistant nylon fabric.
Macerator/chlorinator - a waste treatment device that pulverizes and
chlorinates the waste material in preparation for discharge into natural
waters.
Neoprene^ - Dupont's trade name for an oil-resistant synthetic rubber
based on chloroprene.
NBR - Letter code used in the rubber trade as a generic designation for
synthetic rubbers made from acrylonitrile and butadiene. In this
report it is used synonymously with the term nitrile rubber.
Nitrile rubber - The generic name for an oil-resistant synthetic
rubber based on acrylonitrile.
Nylon - The generic name for all synthetic fiber-forming polyamides.
Polyurethane - The generic name for a synthetic polymer which, depending
on its composition, can be an elastomer or a plastic.
PVC (polyvinyl chloride) - A thermoplastic material composed of
polymers of vinyl chloride: a colorless solid with outstanding
resistance to water, alcohols, and concentrated acids and alkalies.
Compounded with plasticizers it yields a flexible material superior
to rubber in aging properties.
Thermoplastic - Capable of being repeatedly softened by heat and
hardened by cooling.
Self-contained Toilet - A toilet which has a build-in reservoir and
does not require external connections to dispose of sanitary wastes.
Tygon - A trade name for a transparent, flexible plastic which is
highly resistant to chemicals.
Uniroyal Compound No. - A number used to designate a particular
rubber or plastic material in the Uniroyal plant in Mishawaka, Indiana.
Uniroyal Style No. - A number used to designate a particular fabric
in the Uniroyal plant in Mishawaka, Indiana.
36
-------
SECTION VIII
APPENDIX
Photograph
Miscellaneous Photos 38
Use Test Facility 39
Applications Test Facility 40
Installation in Deep Keel 41
Corrugated Tank Installation in Motor Room Open Space -
in Basket 42
Tank Installation - Under Closet 43
Installation in Shallow Keel 44
Installation in Rope Locker 45
37
-------
City of Chicago Pump out
Equipment
Recirculating Hook Up
Rocking Test Stand
Dip Pipe and Swivel Fitting
Miscellaneous Photos
38
-------
Test Room
Recirculating Hook Up Dip Pipe and Fiiter Bag
Use Test Facility
39
-------
Applications Test Facility
(3 Views)
-------
Corrugated Tank
Plain Tank
Empty
Empty
Full
Installation in Deep Keel
Full
-------
Installed on Edge
Installed Flat
(O
Empty
Empty
Full Corrugated Tank Installation
in Motor Room Open Space - In Basket
Full
-------
Plain Tank
Corrugated Tank
Empty
Empty
Full
Full
Tank Installation - Under Closet
43
-------
Plain Tank
Corrugated Tank
Empty
Empty
Full Full
Installation in Shallow Keel
-------
Plain Tank
Corrugated Tank
*—,
Empty
Empty
Full Full
Installation in Rope Locker
-------
BIBLIOGRAPHIC:
Uniroyal, Inc. Flexible Holding Tank for PleaaurecrafC Sanitary System,
Final Report: FWQA Contract #14-12-506, August 1970
The purpose of this effort was to develop a flexible holding tank to
collect waste products in small pleaaurecraft. Ita uae la primarily
proposed as a convenient means for modifying existing craft BO as to
comply with existing and proposed new legislation on the subject of
water pollution.
A survey delineated numerous locations where a flexible tank could
be located in the various craft under consideration and a corrugated
design was conceived which will conform to most of these.
The placement of the flexible tank in several locations was success-
fully demonstrated using a boat mock-up. Performance tests, also
conducted, showed that the tank could be used both as a simple
holding tank or as a reservoir in a recirculatlng sanitary system.
ACCESSION NO.
SANITARY SYSTEM
WATER POLLUTION
HOLDING TANK
FLEXIBLE TANK
BIBLIOGRAPHIC:
Uniroyal, Inc. Flexible Holding Tank for Pleasurecraft Sanitary System,
Final Report FWQA Contract #14-12-506, August 1970
ABSTRACT
The purpose of this effort was to develop a flexible holding tank to
collect waste products in small pleaaurecraft. Its use is primarily
proposed as a convenient means for modifying existing craft so as to
comply with existing and proposed new legislation on the subject of
water pollution.
A survey delineated numerous locations where a flexible tank could
be located in the various craft under consideration and a corrugated
design was conceived which will conform to most of these.
The placement of the flexible tank in several locations was succi
fully demonstrated using a boat mock-up. Performance tests, also
conducted, showed that the tank could be used both as a simple
holding tank or as a reservoir in a recirculatlng sanitary system.
ACCESSION NO-
SANITARY SYSTEM
WATER POLLUTION
HOLDING TANK
FLEXIBLE TANK
BIBLIOGRAPHIC:
Uniroyal, Inc. Flexible Holding Tank for Pleasurecraft Sanitary System,
Final Report FWOjA Contract #14-12-506, August 1970
ACCESSION NO-
comply
water pollution
A survey delineated numerous locations where a flexible tank could
be located in the various craft under consideration and a corrugated
design was conceived which will conform to most of these.
The placement of the flexible tank in several locations was success-
fully demonstrated using a boat mock-up. Performance tests, also
conducted, showed that the tank could be used both as a simple
holding tank or as a reservoir In a recirculating sanitary system.
SANITARY SYSTEM
WATER POLLUTION
HOLDING TANK
FLEXIBLE TANK
-------
Accession Number
Subject
Field & Group
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Uniroyal, Inc., Research Center, Wayne, N. J. 07470
Title
Sanitary Holding Tank for Pleasurecraft
10
22
Authors)
Mark W. Olson
11
Date
August 1970
16
^2 1 Pages
45
Project Number
1502DGR06/70
21
•, c Contract Number
FWQA
14-12-506
Note
Citation
oo Descriptors (Starred First)
25 Identifiers (Starred First)
27
Abstract
The purpose of this effort was to develop a flexible holding tank to
collect waste products in small pleasurecraft. Its use is primarily
proposed as a convenient means for modifying existing craft so as to
comply with existing and proposed new legislation on the subject of
water pollution.
A survey delineated numerous locations where a flexible tank could be
located in the various craft under consideration and a corrugated
design was conceived which will conform to most of these.
The placement of the flexible tank in several locations was success-
fully demonstrated using a boat mock-up. Performance tests, also
conducted, showed that the tank could be used both as a simple
holding tank or as a reservoir in a recirculating sanitary system.
Abstractor
Mark W. Olson
Institution
Uniroyal, Inc.
WR;102 (REV. OCT. 1968)
WRSIC
SEND TO: WATER R ESOU RC ES SC I EN T I F I C INFORMATION CENTER
U S. DEPARTMENT OF THE INTERIOR
WASHINGTON, D.C. 20240
ft GPO: 1969—324-444
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