and dislodge all the rings all the way to the frame. A simple inspection
procedure to determine a loose ring is to look at the panels from the backside.
The joint between any two adjacent rings should be flat and even. Do not tap
or knock on the backside of the bull's-eye. Gently run your fingers down the
length and width of the panel feeling for any member that may be out of
place. If your fingernails get caught on an edge, examine the depth of the
edge and see how much the ring has moved. Many times the rings start to
shift to one side and become cocked as they move out of their seat. If you
find this occurring, carefully apply TYVEK tape to inner surface with a second
person supporting the outside surface. DO NOT APPLY A GREAT AMOUNT
OF PRESSURE ON THE BACK OF THE BULL'S-EYES AS YOU WILL
DISLODGE THE RINGS AND PUSH THEM OUT. The tape will obscure a
small percentage of light from the flash panel, but still provide a suitable
signal until professional assistance can be obtained.
E. Replacement Prisms. Replacement of broken prisms may be necessary to
restore the rated intensity of the light. One or two broken prisms in a barrel
lens lantern will have a minor impact on the rated range of the lantern. A
general approximation for the reduction of intensity of a flash panel (that
contains a bull's-eye) is equal to the area lost divided by the area of the flash
panel. Lenses that are prone to vandalism may eventually need to be
removed from the lighthouse; however, compliance with NEPA and Section
106 of the NHPA must be completed prior to removal of lenses. Such
compliance must include initiating consultation with the applicable State
Historic Preservation Office (SHPO) and coordination with other interested
parties as stated previously in Section 1.C. of this Guide.
Some replacement prisms may be maintained at the light. They may have
been included in the original shipment, or salvaged from another lens.
Sources of replacement prisms and Bull's-eyes are available if a sample of
the damaged piece is available, however the lead-time and cost are high.
Expect to pay approximately ,000 per element. Contact Commandant (G-
SEC-2) for sources of supply.
F. Fasteners. Many classical lenses use unique fasteners to secure the lens
frames, latches, covers and braces as well as parts of the drive mechanism.
Be sure to retain all fasteners, as replacements are difficult to obtain.
G. Additional Assistance. There are resources for those Units not feeling
comfortable performing repairs on classical lenses. There are few Coast
Guard employees considered experts in the field of lens repair. Utilization of
their services generally requires permission from their command and funded
orders to the site. Outside assistance is available on a contract basis.
Contact Commandant (G-SEC-2) for details.
7-3