The shorter whip should hold up better than the long one. It would be
good to determine the frequencies your coast stations will be using and
confirm that your antenna tuner will handle those frequencies with the
17 foot whip.

You don't want to use metal guy wires so close to the antenna. Dacron
would probably be a better choice than stainless for the guys. It also
has some stretch to it. I would think 3/16" braided dacron would be more
than adequate for the purpose. The metal wires could affect antenna
performance, but there's no real danger to people in the pilothouse.
There's another advantage to aluminum! The greater difficulty is that if
you attach the guys at 8 feet up, the angles to the corners of the
pilothouse will be really small, which is not so good. It would be
better at 3-4 feet up, but they guys won't help much if they are that low.

You'll probably get some additional insights as you mount and attempt to
guy the antenna.

If the pilothouse roof is aluminum, you're in good shape. Mount the
tuner close to the base of the antenna and you should be fine.

Good luck!

Chuck

bradleyj wrote:
Thanks again for everyone's input.

To clarify why I am installing a SSB. My boat is a 28' documented
vessel with a fisheries endorsement. I fish commercially as much as
100 nm from shore. Any documented commercial fishing vessel operating
outside of VHF radio range from shore stations (maybe 25-30 miles on a
good day) is required by the Commercial Fishing Vessel Safety Act to
carry a MF/HF radio. I have my FCC ship station license and restricted
radiotelephone operator permit. I also have a 406 MHz Type 2 EPIRB
(also required by law) and other safety devices too numerous to name
(also required by law). All I really need to be able to do is contact
the nearest shore stations. I'm not looking to talk halfway around the
world.

Now back to the installation. I'm leaning toward a guyed installation
on the pilot house roof. This will get the antenna up and away from
all metal structures. I drew up a sketch of the concept, but I still
can't seem to upload any picture files to this server. I'm planning on
going with a Shakespeare 5390 17.5' fiberglass coated whip. I'm
thinking of attaching three stainless guy wires about 4' up from the
base. The idea I have for attaching anchors for the guy wires is to
fabricate three aluminum brackets with holes to clip the guy wires to
and installing them 120° apart on the antenna whip by wrapping them
with fiberglass tape and encapsulating with resin, much the same way
that the eyes on fishing rods are attached to the rod blanks. The
stainless steel guy wires will attach to three points on the edge of
the pilot house roof. My question is will these metal brackets and guy
wires cause problems with antenna performance (or roast the occupants of
the boat)? The brackets will be electrically isolated from the
conductors inside the whip by the fiberglass coating on the whip, but
will RF energy still be affected (shunted down through the guy wires to
the pilot house)? Does anyone else have any other ideas?

Brad