"Kelton Joyner" wrote "Dear Capt. Mooron" with this
lament:

Dear Capt. Mooron

| My depth sounder only reads to 500'. At 1.5 miles offshore I'm in over
| 500' of water depth. How can I chart the bottom contours?
signed: Over My Head

Dear Over My Head,
This is a common problem for coastal sounders used in deep water. I suggest
you upgrade to a larger more powerful professional grade unit. If this
proves not practical just use your advanced knowledge of seastate to confirm
your multiple GPS, Sextant and Dead Reckoning Plots. Once you return to the
continental shelf your cheapo coastal unit will once again provide
confirmation of correct seafloor contours. I have toyed with the idea of
using powerful underwater speakers and a sound system approaching the power
generated by the unit currently on Bob's boat "Alien"... this could be
utilized to scramble the sonar array on passing subs. Once they surface to
investigate the cause you can inquire as to the actual depths as they board
your vessel. Good Luck and Fair Winds.

Capt. Mooron