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Non-metal yacht
Yachts with a wooden or GRP body require additional lightning
protection measures.
If the mast is made of e.g. wood, an air-termination rod with metal mast
a thickness of at least 12 mm must protrude at least 300 mm
from the mast. The down conductor routed down the mast can upper shrouds
be made of copper and should have a minimum cross-section
2
of 70 mm . It must be routed in the outdoor area of the yacht
and connected to the earth plate. The earth plate must have ball pin
2
a surface of at least 0.25 m and must be made of copper screwed to
or another saltwater-proof material. In case of large yachts, the mast
different earth plates may have to be used for the lightning
protection and power supply system. In this case, a sufficient
distance must be maintained between these earth plates to
prevent flashover.
If lightning strikes the air-termination rod on the non-metal
mast, the lightning currents must be discharged to the earth
plate via the down conductor on the mast and via the shrouds,
stays and chain plates. To this end, the mast, shrouds, stays and
chain plates must be connected to the earth plate. The copper
connecting conductors must have a minimum cross-section of
2
16 mm . All lightning current carrying connections may only be
established by screwing, riveting or welding.

Mobile lightning protection in case of a metal mast Component Type/material Part No.
A cost-effective mobile lightning protection system, which is Universal earth-
frequently used for occasional charters of a yacht, can be eas- ing clamp UEK 25 HG 774 234
ily implemented. To this end, the lower part of the aluminium
mast is fitted with a ball pin, which is used as down conductor. Can be configured
A lightning current carrying terminal, which is connected to Multipole via the DEHN
two other terminals and two braided copper strips of several earthing cable e.g. V6TZ3N8 earthing and
metres, is screwed to the ball pin. The terminals are connected short-circuiting
to the upper shrouds to use them as down conductor. The free configurator
ends of both braided copper strips must be immersed at least Earthing tongs Stainless steel 546 001
1.5 m in the water (Figure 9.34.3).
All components and the relevant connections must be capa- Braided copper Copper 377 007
ble of carrying lightning currents and must be corrosion-proof. strip
This protection measure can be quickly implemented when Figure 9.34.3 Mobile lightning protection for a yacht with a metal
a thunderstorm approaches and provides a certain protec- mast
tion against lightning strikes. It is not entirely clear to what
extent mobile lightning protection systems provide protection
for yachts since the normative requirements for equipotential power supply circuits (shoreside power supply system) of wa-
bonding (personal protection), separation distances, etc. are ter sport vehicles and house boats supplied by public utilities.
not observed. It can only be assumed that lightning damage Water sport vehicles include boats, ships, yachts, motor launch-
such as punctures of the body can be prevented since most of es and house boats which are exclusively used for sports and
the lightning current flows through the braided copper strips leisure activities.
into the water. Therefore, a fixed lightning protection system The information provided only refers to single-phase alternat-
always has to be preferred. ing current power supply systems in a 230 V/50 Hz system (it
can be also used for three-phase power supply systems in a
Power supply system modified form). The relevant socket outlets up to 63 A must
The IEC 60364-7-709 (HD 60364-7-709) standard (marinas comply with the IEC 60309-2 (EN 60309-2) standard (CEE de-
and similar locations) describes the special requirements for sign, “blue”).

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