Smith-Root ELECTROFISHING BOATS, User Manual, Page: 39 / 53

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USER'S MANUAL
as horizontal handrails on cabin tops, smoke stacks from
galley stoves, davits, or metal signal masts.
INTERIOR BOdIES OF METAL
Metal situated wholly in the interior of boats and which at
any point comes within 6 ft (1.8 m) of a lightning conductor
should be electrically interconnected with this lightning
conductor.
Interior bodies of metal include engines, water and gasoline
tanks, and control rods for steering gear or reversing gear. It
is not intended that small metal objects such as compasses,
clocks, galley stoves, medicine chests, and other parts of the
boat’s hardware be grounded.
Metal that projects through cabin tops, decks or sides of
boats above the sheer should be bonded to the nearest
lightning conductor at the point where the metal emerges
from the boat and should be grounded at its lower or extreme
end within the boat.
Radio transmitter antennas should be (a) equipped with
means for grounding during electrical storms or (b)
transmitters and antennas should be protected by lightning
arresters or lightning protective gaps.
Ground Connection. A ground connection for a boat may
consist of any metal surface that is normally submerged in
the water and that has an area of 1 square foot (0.093 m2).
Propellers and metallic rudder surfaces may be used for
this purpose. The ground plate as required by the Federal
Communications Commission for radio transmitters should
be considered adequate. A metal hull itself constitutes an
adequate ground.
Vessels with Metal Hulls. If there is an electrical
contact between metal hulls and metal masts or other
metallic superstructure of adequate height to meet the
recommendations of Section 2, no further protection
against lightning is necessary. Boats with ungrounded or
nonconducting objects projecting above the metal masts
or superstructure should have these objects grounded or
protected with a grounded conductor, respectively, in order
to protect them.
PROTECTION OF SAILBOATS (NONMETALLIC)
Sailboats. Sailboats with metallic standing rigging will be
adequately protected provided that all rigging is grounded,
so that the mast and rigging meet the recommendations of
Sections 2 and 3.
Open Day-Sailors. Open sailboats will be adequately
protected if any shrouds, backstays, or preventors, and
any continuous metallic track on the mast and boom are
grounded. These should be electrically connected at the
lower or forward end and grounded to a copper plate on the
hull or to a metal rudder, centerboard, or keel.
Cruising Sailboats. All stays and all sail tracks should
be grounded on cruising sailboats since it is assumed that
persons will be in proximity of fore-stays as well as after-
stays. Grounding of other objects on cruising boats should
be in accordance with the foregoing subsections.
PROTECTION OF POwER BOATS
(NONMETALLIC)
Power boats may be adequately protected by a grounded
radio antenna and other suitable grounded lightning
protective mast provided the height of the mast meets the
recommendations for the zone of protection in Figure 2.
Interconnection and grounding of metallic masses should be
in accordance with previous materials.
Where the size of the boat is such as to render the use of a
single mast impractical, additional lightning protective masts
should be erected to form overlapping zones of protection.
Protection of Small Boats. Small boats may be protected
by means of a temporary lightning protective mast which
may be erected when lightning conditions are observed in
the distance. Grounding provisions may be made by means
of flexible copper wire and a submerged ground plate of at
least 1 sq ft (0.093 m2) in area.
PROTECTION OF SHIPS
Ships almost invariably are constructed with steel masts,
spars, superstructures, hulls, smokestacks, and shrouds
and the array of masts, stacks, and radio antennas usually
provide the zones of protection recommended in Figure
2. Therefore, ships and personnel aboard them are usually
inherently protected against the effects of lightning. In those
LIGHTNING PROTECTION