COMMON MYTHS ABOUT BOATING AND BOAT BUILDING
In every culture there are myths and urban
legends that grow up and get passed on mostly by word of mouth. How they
get started is hard to tell. Boating is no exception. There are many of
these myths that surround the boating life. I do not mean the
superstitions, such as don’t whistle on a boat, or don’t launch a boat
on a Friday. This is about technical myths.
All of the following are statements I have heard people say, or I have
seen in print. It always amazes me how seemingly competent people can
continue to pass these on. I have even heard marine professionals say
these things. It also amazes me that boat owners don’t take the time
to check the Internet or read books to find out the facts.
Belief: Styrofoam flotation is banned by
the Coast Guard.
Not True: Styrofoam may be used as flotation.
33 CFR Subpart F - 183.101 -183.335 Flotation
§183.112 Flotation material and air chambers.
(a) Flotation materials must meet the requirements in §183.114 as
listed in Table 183.114 when used in the: (1) Engine room bilge, (2)
engine room, or (3) bilge, unless located in a sealed compartment.
Any means can be used to achieve the flotation requirements such as foam,
air chambers, balsa, and other materials. The
Coast Guard requirement says that if you use flotation materials and if the
flotational material is exposed
to gasoline, oils or other chemicals that would degrade it, it must be
resistant to these substances. The most common flotation material is
foam. Some are resistant to degradation. Polyurethane foam is. Styrofoam is not. However, you
can use Styrofoam anywhere it isn’t exposed to these substances, or
anywhere if the foam is encased. Foam isn’t even required. It just happens
to be the easiest and most convenient solution. See the next
myth.
Belief: "I am planning on using
Coast Guard Approved Flotation Foam"
Not True:
33 CFR Subpart F - 183.101 -183.335 Flotation See 183.114. There is no such thing. The USCG does not
approve flotation foam. Approval applies to certain items you must carry
on board a boat. This includes things such as Fire Extinguishers, Personal
Flotation Devices, and visual distress signals. Also some courses and
schools for professional mariners are Coast Guard Approved. Flotation foam
is not. Any one telling you they are selling Coast Guard approved
flotation foam is violating the law and lying to you. If they say it meets
the requirement of 33 CFR 183.114 then that means they, the foam
manufacturer, have tested it for resistance to gasoline, oils, bilge
cleaners, etc. and it can be used in the bilge or areas where it is
exposed to these things. But that is not Coast Guard Approval. Approval
means that the Coast Guard has not only looked at the item and inspected
it, but also tested it to see that it meets all of the regulations that
apply. The Coast Guard does not do that for foam.
Coast Guard Certification and Approval:
https://newboatbuilders.com/pages/certified.html
US Coast Guard Approval:
https://cgmix.uscg.mil/Equipment/Definitions.aspx
Belief: The Coast Guard requires Battery Boxes (or ABYC does)
Not true Here is the USCG regulation.
33 CFR 183.420
Sec. 183.420 Batteries.
"(a) Each installed battery must not move more than one
inch in any direction when a pulling force of 90 pounds or twice the
battery weight, whichever is less, is applied through the center of
gravity of the battery as follows:
(1) Vertically for a duration of one minute.
(2) Horizontally and parallel to the boat's center line for a duration
of one minute fore and one minute aft.
(3) Horizontally and perpendicular to the boat's center line for a
duration of one minute to starboard and one minute to port.
(b) Each battery must be installed so that metallic objects cannot come in
contact with the ungrounded battery terminals.
(c) Each metallic fuel line and fuel system component within 12 inches and
above the horizontal plane of the battery top surface as installed must be
shielded with dielectric material.
(d) Each battery must not be directly above or below a
fuel tank, fuel filter, or fitting in a fuel line.
(e) A vent system or other means must be provided to
permit the discharge from the boat of hydrogen gas released by the
battery.
(g) Each battery terminal connector must not depend on
spring tension for its mechanical connection to the terminal."
Notice, it does not say how the battery should be
constrained or how to prevent inadvertent contact by shielding it. A
common method is to put the battery in a ventilated box. However,
the Coast Guard does not require a box. The battery may be held with
a strap or clamps and it can be shielded with boots on the terminals.
It can also be in a tray that keeps it from moving and will hold any
spillage.
Here is the NFPA wording for batteries. It does not say they have to be in
a battery box. It allows for other means of compliance.
NFPA 302 says: in 302-7.3
“A vent system or other means shall be provided to allow the discharge
from the boat of hydrogen gas released by the battery. Battery boxes with
a cover that forms a pocket over the battery shall be vented.”
“Batteries shall be secured to provide immobilization to
the extent practicable.”
“Batteries shall be located in a liquid tight tray or battery box of
adequate capacity to retain normal spillage or boilover of electrolytes.
The tray shall be constructed of or lined with materials resistant to
deterioration by the electrolytes.”
“A non conductive, perforated cover or other means shall be provided to
prevent accidental shorting of the ungrounded battery terminals and cell
conductors.”
ABYC says similar things. Standards for batteries are found in
ABYC E-10. Nowhere does it say they must be in a battery box, and it
provides alternative means to comply. Obviously the easiest way of
meeting these requirements is a battery box, but it is not required and it
is not a regulation.
Belief: If I change to a bigger Group Size battery I can increase
my battery capacity:
This is one I have encountered in not only the boating community but in
the RV world as well and anywhere automotive type batteries are used.
I have seen it in boating magazines, and web sites. I have seen
"experts" tell people that all they need is a larger group size. This one
is usually related only to deep cycle or combo starting/deep cycle house
batteries. Combo batteries are usually marketed as RV/Marine
batteries. Usually the person wants to add equipment and needs more
capacity or simply wants to make their batteries last longer.
Not true. The Battery Council International defines Group size as
solely the physical dimensions of the battery.
The BCI (Battery Council International)definition of Group Number is:
"BCI GROUP NUMBER- The BCI Group Number defines a battery by describing
the following characteristics:
A.) Its maximum dimensions (L x W x H)
B.) Voltage (6 volt or 12 volt)
C.) Post configuration
D.) The type of terminal used (top, side, flag, etc.)
It should be noted that the BCI Group Number does not designate a
battery's capacity, it merely defines the above listed physical
characteristics."
To increase battery capacity you need a battery with a higher CCA or MCA,
or Amp Hour rating. Or you need to connect several batteries of the same
capacity in parallel. You can also increase capacity by going to
true deep cycle batteries, such as golf cart batteries (normally 6 volt)
or D8 batteries. True deep cycle batteries have more and thicker
plates in them than combo batteries and tend to release energy slower and
longer than combo style batteries.
Belief: Do it yourself AC wiring: "It is now illegal to use
ROMEX or solid core electrical wire in boats – Many older boats are
grandfathered provided it was wired that way at the factory. If you
wired it in the last 10 years it must be done with stranded copper wire
only. NFPA 302 – ABYC – CFR 33"
Not True: I took this quote off a boating web site. This
is really misleading. It is not illegal to wire your boat yourself. The
Coast Guard requirement for stranded wire applies to boat manufacturers
not owners. 33 CFR 183.425 says “a) Each conductor must be insulated,
stranded copper.” But, that regulation does not apply to boat
owners. Both ABYC and NFPA require stranded copper wire but they are
voluntary standards. You will not pass a survey if you have Romex
(house wire), solid core wire, aluminum wire or automotive wire, but it is
not illegal for the owner to use it. But, it is not good practice.
Boat owners should use marine wire, usually
labeled UL 1426 Boat Cable. Stranded copper marine wire is required on new
boats because it is safer and will last a lot longer. Marine wire is more
flexible and less prone to breaking and corrosion than solid core wire or
auto wire. The insulation is more resistant to oils and cleaners and other
chemicals found on boats than on non-marine wire.
Belief: ABYC
requires Tinned wire.
Not True. ABYC E-11 Electrical
Systems E-11.14.2.4 says: "Conductors and flexible cords shall be stranded
copper according to
TABLE XI."
Tinned wire is recommended and can be used but it
is not required by ABYC.
Belief: ABYC does not allow soldered
connections:
Not true. ABYC allows soldered
connections but they cannot be the sole means of support for the wire.
"E-11.14.5.7 Solder shall not be the sole means of
support of mechanical connection in any circuit. If soldered, the
connection shall be so located or supported as to minimize flexing of the
conductor where the solder changes the flexible conductor into a solid
conductor"
Belief: "Anything
electrical within 7" of a battery will become corroded in a average boat."
Not True. Where this came
from, I don't know but I got the quote off a boating forum.
What they were referring to was the requirement
for fuses or circuit breakers to be within seven inches of the source of
power. Why this would cause corrosion is beyond me.
Belief: If your boat has corrosion
on the sterndrive or other underwater metal fittings you can stop it by
cutting the green wire.
Not True. The green wire,
the third wire in AC electrical system, is there to protect you against
shock. Cutting it will not stop corrosion on your boat.
The explanation is much too long to go into here.
See
Corrosion On Boats. But cutting the green wire in the AC system
will cause a serious hazard of shock to people on the boat.
Corrosion is caused by other factors, such as DC current leaking into the
water.
Belief: Recreational Boats must be Coast
Guard Approved (or certified).
Not True: The Coast Guard does
not certify or approve recreational boats. The terms US Coast Guard
Certified and US Coast Guard Approved have specific meanings defined by
law. Recreational boats are certified, but it is the builder or
manufacturer who must certify that their boats meet the requirements of
the Federal Regulations. See
https://newboatbuilders.com/pages/certified.html for more information.
Belief: Foaming in tanks. Encasing a tank
in foam is a good way to protect it and support it.
Not A good Practice: I believe
that foaming in a tank is a death sentence for a metal tank. I could
go on at length about this (and on occasions I have) but the surest way to
trap moisture against a tank and cause it to corrode is to encase the tank
in foam. This is why the USCG made the installation of fuel tanks
encased in foam so difficult.
Sec. 183.516 Cellular plastic used to encase fuel tanks. Put simply,
the bond between the tank and the foam breaks and moisture collects
between the foam and the tank. It has no way out and does not
evaporate. The tank corrodes.
ABYC Standard H-24 Gasoline Fuel Systems says the
same thing as the USCG regulation. However, there are boat builders who
believe that foaming in tanks is the way to do it. This is a controversial
subject and there has been a lot of debate about it over the years.
Belief: All fuel system hose must be
double clamped: Not True: 33 CFR Subpart J Gasoline Fuel Systems
Sec. 183.558 Hoses and connections.
(b) Each hose used—
(1) For a vent line or fill line must be: ..........
(c) Each hose must be secured by:
(3) A hose clamp.
The USCG requires double clamping, and so does
ABYC, on fuel fill and fuel lines but the USCG is silent on how many
clamps on a vent line. ABYC specifically says single clamped.
ABYC H-24 Gasoline Fuel Systems"24.12.9
Hose connections used in the fuel tank vent system or
the fuel distribution and return line system shall have at least one
corrosion resistant metallic clamp with a minimum nominal band width as
indicated in H-24
TABLE III."
So vent lines may be single clamped. But I
recommend you double clamp if possible for an extra measure of safety.
Unfortunately some of the vent fittings on the market are not long enough
for double clamping, so when you buy your fittings look for ones that are
long enough.
Belief: "Loop's in fuel lines are a Coast
Guard/ABYC violation. Fuel must flow downhill to the tank without
any traps as it can be a fire hazard if the boat burns."
Not True:
This is a direct quote from a boating forum. The writer was
speaking about the fuel tank vent line. Loops are not prohibited by the
USCG or ABYC. The vent line needs a means of preventing water from
entering the system, per ABYC.
"H-24.14.6
The tank vent system shall prevent the intake of water when tested to
section H-24.18 Installation tests"A loop is one means of doing this.
The USCG fuel regulations doesn't even mention
this. See 33 CR 183.501
https://newboatbuilders.com/pages/33CFR_Fuel.html
Belief: Your powerboat must have an
Anti-Siphon valve:
Not True.
33 CFR 183.568
The US Coast Guard requires an anti-siphon valve on inboard powered
boats with permanently installed fuel systems, if the fuel tank is
higher than the fuel inlet on the engine. That means if the fuel
line runs down hill from the tank to the engine, you need an anti-siphon
valve. If it runs uphill, that is the fuel inlet on the engine is
higher than the tank, then you don’t need one. These little valves
cause a lot of problems and are always getting clogged by junk in the
fuel. If you don’t need it, get rid of it. They are not
required on outboard boats. ABYC standards do require them on outboards
with permanently installed fuel systems, but only if the fuel system can
siphon itself, which is the same as the USCG requirement for inboards.
Belief: The Coast Guard (or ABYC) bans
Stainless Steel tanks:
Not true: The only tank material
that is banned is ternplate, a tin-lead metal that is very prone to
corrosion. Stainless tanks are permitted. However, they are
very prone to a condition called crevice corrosion, so ABYC recommends
they be 20 gallons or less with domed ends. This minimizes the welds
where they are most subject to corrosion. They should be mounted where
they will be dry and can be inspected on all sides. Only 316L or
317L stainless should be used. As with all the above, tank
regulations are manufacturer requirements.
Belief: "Look at ABYC H-24 Gasoline
Fuel Systems. Gasoline fuel tanks may not be installed in engine
compartments."
Not True: ABYC does not prohibit
fuel tanks from being installed in engine compartments. This is why
ignition protection, ventilation, and fuel systems regulations exist.
Fuel tanks are frequently located close or in the same compartment as the
engine.
Belief: It is illegal to exceed the
horsepower rating on my boat.
Maybe; Why maybe? This is a
gray area. The Federal regulation requires boat manufacturers to post a
label with the recommended maximum safe horsepower for outboard powered
boats. It only applies to mono-hull boats under 20 feet in length.
Horsepower is determined using a formula contained in the regulation.
Under Federal law a boat owner can put any size engine they want on their
boat. However, the catch is, some states have passed laws making it
a violation to exceed the values on the capacity label. Insurance
companies also may cancel your insurance if they discover the boat has an
engine that exceeds the horsepower rating. If you have an accident
and an investigation shows it was related to overpowering then the owner
could be held liable in a law suit by the injured parties.
The Following Item Has Been Revised
Circumstance: I was cited by the police for not having a
capacity label on my boat: AMENDED 01/10/2011
This could be a requirement: Previously I had
said this is not a requirement. However a law enforcement officer who is
very knowledgeable about boating law questioned this. In his state
the law makes this both a manufacturer and owner/operator requirement. So
I queried the US Coast Guard to get a clarification. This is the response;
“Several states have passed laws requiring
operators to have a capacity plate on their recreational boats. To
date, Pennsylvania is the only State that I am aware of that actually has
a website for operators to get a capacity label. I get many phone
calls from boaters in States with such laws that have no idea where or how
to get a label. We do have preemption authority but we don't
normally use it on operator requirements such as a capacity label, or
speed limits, or proximity to other vessels, or wearing life jackets from
November to March, etc. The Alabama kill switch was an attempt at a
manufacturer requirement that we preempted. You need to change your
web-site to make it clear that a capacity label is a manufacturer
requirement except in States that have made it an operator
requirement.”
The label is a manufacturer requirement. But the
boat owner can be held responsible for the label in some states.
Only Pennsylvania has a system in place to issue the label to boats that
don’t have one. If your boat is missing the label you should try to
get a new one from the boat manufacturer. If the manufacturer is no
longer in business, or the boat is so old the manufacturer no longer
stocks the labels, you can have one made. But first you need to know
what the values were that were on the label.
The US Coast Guard does not keep records on the
capacities and does not supply these labels to manufacturers. The
manufacturers make them or have them made by an outside source. So if you
need one you will not be able to get it from the Coast Guard. However,
they may be able to help you with the correct format for the label if you
are having one made. See
https://newboatbuilders.com/pages/labels.html
Belief: I have both a capacity label
and a label showing the number of seats. If the seating label has more seats
than people on the capacity label, then I can use the seating label as the
capacity.
Not True: The seating label
is placed on the boat voluntarily by boat manufacturers to show you where
it is safe to sit. This grew out of boat manufacturers trying to
find a way to show boat operators and passengers where it is safe to sit
to prevent injuries and deaths. Even though it is common sense that
it is unsafe to sit on a gunwale, or transom, or the bow, and especially
on pedestal seats when the boat is underway, some people just don't get
the word. Boat operators often fail to follow safe operating basics, such
as sitting in designated seats when the craft is on plane, maintaining a
balanced load or giving themselves an unobstructed view from the helm.
Many boats have casting platforms, storage lockers and other surfaces
which are inappropriate for seating when a boat is on plane. So the
American Boat and Yacht Council and the National Marine Manufacturers
Association developed a label showing where it is safe to sit. It is
simply an information label.
Recreational boat manufacturers are required to
put a capacity label on mono-hull boats under 20 feet in length. The
number of persons on the capacity label is the number you should use.
You will see a similar label on many other types of boats, including
canoes, kayaks, pontoon boats and inflatables. The manufacturers
voluntarily (in the USA) put these on other boats because it is good
business and safety sense to do so. In Canada and Europe the label is
required on all recreational boats (with a few exceptions).In the USA
the label is a manufacturer requirement. The boat owner does not have
any responsibility under Federal law for this label, not even for
complying with the values on the label. (they do in Canada) However,
most states have passed laws making it illegal in the particular state
to exceed the capacities on the label. So if you live in one of those
states you can be cited by state or local law enforcement for exceeding
the capacity on the label. Also your insurance company may take a dim
view of exceeding the capacities. So, use the Capacity Label as a
guide to how many passengers you can carry, and the seat label as a
guide to where they can safely sit.
Belief: I have an old boat with no
capacity label, but I found a formula in a boating book that says if I
multiply length (L) times the width of the boat (B for Beam) and divide
by 15 that will tell me how many people I can carry.
Maybe: This formula, L X
B/15, has been around a long, long, time. I have traced it as far
back as the 1940’s. In the boating world, that is ancient. It has
shown up in a lot of well respected boating publications, books, and even
in the US Coast Guard Boatbuilders Handbook. It is not the formula that
boat manufacturers and builders are required to use to determine persons
capacity for recreational boats, or for commercial passenger carrying
boats. The formula is a rule of thumb. It is only meant to be used as a
rough estimate. It is in the handbook only as a way to estimate the number
of passengers. It is also only intended for use with small mono-hull
boats, usually outboard powered but it has been used for small inboards.
It should never be used for boats more than 25 or 26 feet in length.
It is simply not applicable to larger boats. It also does not apply to
canoes, kayaks, multihulls, inflatables, or pontoon boats.
Belief: The US Coast Guard uses 160
pounds per person to rate the capacity of recreational boats and/or
commercial boats. I hear this one everywhere. It was recently stated
in a BOATUS article.
Not True: Here is an e-mail I
sent to BoatUS concerning this.
"The Coast Guard does not and has never used 160
pounds per person for capacity ratings on recreational boats. This is a
common boating myth and where it got started is beyond me.
But since I spent 25 years working in the Coast Guard Office of Boating
Safety I think I can explain how capacity is determined.
It starts with displacement weight. Displacement weight is the amount
of weight a boat would displace if you weighed the hull down to the
point where water would start to come in. Essentially that is the weight
it would take to sink the boat. That amount is divided by five for
outboard boats, and by seven for inboards. The result is the Maximum
Weight Capacity. That is the amount of weight you can safely put in the
boat including motor gear, batteries, controls and people. To find the
persons capacity you then subtract the outboard motor weight, batteries,
full fuel tank. But a manufacturer must use the outboard weights in the
Coast Guard's Table, or the ABYC table for outboard weights. The result
is persons weight in pounds. To find the number of persons those pounds
represent, the Coast Guard uses a formula: persons weight plus
32 divided by 141. The result is rounded to the nearest person.
Also the boat manufacturer does not have to use
this maximum number. They cannot exceed the numbers for maximum weight
capacity, maximum persons capacity and persons but they can use a smaller
number, and many manufacturers do downrate. The amount of flotation that
goes into the boat is based on; the hull weight, the persons weight and
the outboard motor weight.
For inboards a similar exercise is used to
determine maximum weight capacity, maximum persons capacity and persons.
But the engine is not treated separately. It is considered part of hull
weight.
Perhaps the confusion comes from commercial vessels.
On the commercial side of the Coast Guard they use a persons weight to
determine how much weight to use when performing stability tests. Here s a
quote from a paper on this on my web site entitled How Much Of A Load Is
Too Much?:
On a commercial vessel, the number of passengers is
estimated based on the lesser of the following criteria:
1. Length of rail: one passenger for each
30 inches of rail at the sides and stern., or,
2. The deck area; one passenger per 10
square feet of deck area, excluding spaces listed in 46 CFR 176.113, which
include, among other areas, concession stands, toilets, lifesaving gear
storage spaces, required aisle area, or
3. The fixed seating areas, or fixed
seating; one passenger for each 18 inches of fixed seating width.
The stability of the vessel is then
determined using the number of passengers allowed based on the initial
determination. An SST (simplified stability test) is conducted, based on
the Coast Guard criteria of 140 pounds per person. If the boat does not
pass the stability test then the number of passengers is based on the
weight of passengers that would pass the test at 140 lbs per passenger.
The Ethan Allen investigation has determined that this weight is too low,
and should be at least 174 pounds. The Coast Guard has raised it
to 184"
See
HOTTOPICS; How
Much Of A Load Is too Much?
https://newboatbuilders.com/docs/safeloading.pdf
However, I was inaccurate. The figure
140 pounds per person was used for boats with a combination of adults
and children, but if all the passengers were adults, then 160
pounds was used. But still, that is for commercial boats, not
recreational. For recreational boats the number 141 is not a
weight. It is a constant that was found by analyzing capacities of
recreational boats.
Belief: Galvanic Corrosion Vs
Electrolysis.
Which is the correct term? I still hear a lot of
professionals, let alone amateurs, referring to Galvanic Corrosion as
Electrolysis. The differences are complex although they are similar
processes. But the correct term is galvanic corrosion. See
Corrosion on Boats
https://newboatbuilders.com/docs/CorrosionOnBoats.pdf
Belief: You shouldn't use aluminum
boats on salt water.
Not True: Another complete myth.
Aluminum boats do just fine on salt water. Builders who make
aluminum boats should use marine grade aluminum in the 5000 or 6000
series, such as 5052 or 5083. These alloys are made specifically to
resist corrosion in the marine environment, especially salt water.
The aluminum can be left bare, because it has a natural oxide coating, or
it can be painted. But painting aluminum involves a process you must
follow for the paint to adhere correctly, and endure. Also the boat
should be protected from corrosion by anodes (some call them zincs
although they are many different alloys) and by correctly installing the
electrical system to prevent stray currents on the hull or in the water.
If the boat has an Alternating Current (AC) system on board it should have
a galvanic isolator or an isolation transformer to protect it from stray
current corrosion as well. But if properly built and well maintained
an aluminum boat will last as long as any other material. For
more info on aluminum see
https://newboatbuilders.com/docs/aluminum.pdf
Belief: Cored Composites are stronger
than solid laminates.
Not True: See
https://www.passagemaker.com/technical/mythbuster-infused-hulls-stronger.
Many thanks to Phil Friedman for this one.
This is a new one!!
Belief: " I
was told that butt connectors to hook up a bilge pump are the only way the Coast Guard is happy."
(found on a boating forum 06/27/2020
Not True:
This is another good example of someone being told something
by someone who doesn't know what they are talking about.
The Coast Guard does regulate some wiring on boats but not
the type of connections used to hook up the bilge pump. See
33CFR 183.401
https://newboatbuilders.com/pages/33CFR_electrical.html
Copyright newboatbuilders.com 2012 revised
01/27/2022 All Rights Reserved
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