A few questions & thoughts:
- Why on earth do you need to haul out
in order to change out your zinc? That has to be crazy expensive, given how often your doing it, coupled with your boat's size. Non?
- Fiscally, it only makes sense to switch to a prop where the above isn't the case. Especially as there are more efficient propellers out there.
Because between; not needing to haul in order to change zincs, not needing to change zincs so frequently, & getting better prop performance (under sail AND power), it only make sense to change to another brand/type.
I mean the new prop would pay for itself in under a year, even without selling the old one. Which is obviously possible, & advisable.
- How cold can the water be?
I mean I regularly swim in tne N. Sea when I'm over in Scotland
. Ditto in Puget Sound
, where water temp. is 40 - 45 deg. F (5-8 deg. C).
Without a drysuit or wetsuit, in the dead of Winter, out near the Pacific Coast (Ocean proper).
Also, there are no shortage of divers in the PNW; recreational, & commercial
, who only wear wetsuits. So I can't see water temp being that big an issue, regardless.
I mean guys even dive though the ice, sans heated wetsuits. Which are what professional divers wear when working in very cold waters for extended periods.
- Why not switch to a bigger zinc? Even if it means either; having some oversized zincs custom machined, the prop. machined, or both?
- Has anyone done a current survey in your marina, like your insurer for example? As if there's stray current in there, I'm SURE that they'd take a STRONG interest in it.
- Have you tried hanging a zinc fish
which is directly connected to your shaft?
- There are other options as well, in order to literally stop
such problems. But they're a bit exotic, & Far too expensive for this application.
The part about more efficient propellers has been covered extensively on here before; including a posting
of the test in the May '09 Yachting Monthly
magazine. Plus, of course, there's lots of info on same via an online search.