Not a bad idea, if Wireman's Flex Weave is stainless steel. Anything
else will be corroded before you know it. Perhaps stainless steel
aircraft cable?

Absolutely. Replace your 50 feet of copper with stainless steel wire. Mount it
carefully and you'll get 10 years out of that. Keep the tuner. Its one thing to
have resonant lengths or traps on the harmonically related ham bands but
someday, when the swell is 25 foot in a force 9 and your drifting towards
rocks, being able to instantly tune and call on 2182Khz or one of the higher
distress freqs may very well save your life, believe me, Im a lifeboat man.
But, taking others views on board, as part of your regular planned maintenance
(you do that dont you?), take the lid off your transciever AND tuner to check
for corrosion, youll recognise it as white flaky stuff where the shiny bits
were last year! Other than that, your tuner is no more likely to breakdown than
anything else on your boat.

John, G0WPA